• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.428-435
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• 2019

The rapid increase and dissemination of carbapene mases, such as Klebsiella pneumoniae carbapenemase (KPC), has become a major problem within the field of healthcare-related infection. There are few antibiotics to treat carbapenem-resistant Enterobacteriaceae (CRE) infections, so the identification of resistant bacterial mechanisms is critical to initiate infection control and conduct epidemiological research. A rapid and effective method for detecting KPC-producing bacteria is needed to avoid therapeutic failures and introduce measures to prevent and control the dissemination of these multi-resistant bacteria. During the study period, 31 isolates (seven isolates of Acinetobacter spp., six isolates of Morganella morganii, five isolates of Pseudomonas aeruginosa, five isolates of Proteus mirabilis, one isolate of Proteus vulgaris, two isolates of Enterobacter cloacae, one isolate of Enterobacter aerogenes, one isolate of Klebsiella pneumoniae, one isolate of Klebsiella oxytoca, one isolate of Serratia marcescens and one isolate of Escherichia coli) were identified by the VITEK. Gram negative rod bacteria were the most frequently isolated from urine (35.5%), blood (19.4%), sputum (16.1%), pus (9.7%), ascitic fluid (9.7%), tracheal aspirates (6.5%) and bile juice (3.2%). Analysis using the PCR method identified the bla_KPC gene in the K. oxytoca1 strain, but the bla_IMP, bla_VIM and bla_OXA-48 genes are not amplified. In conclusion, diagnosis using the PCR method can accurately and quickly diagnose KPC, thus establishing quick preventive measures to prevent the spread of KPC in hospitals.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.417-423
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• 2000

Lactobacillus plantarum KLAB21 isolated from Kimchi has been reported to produce antimutagenic subtance(s) in the culture medium. In this study, antimutagenic effects of the strain KLAB21 were investigated to under various culture conditions maximize the production of antimutagenic substance(s) against N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) on Salmonella typhimurium TA100 and 4-nitroquinoline-1-oxide(NQO) on S. typhimurium TA98. Glucose(2%) as a carbon source and yeast extract(1%) as a nitrogen source resulted in the highest production of the antimutagenic substance(s) against both mutagens in the culture supernatant of L. plantarum KLAB21. The most effective concentrations of bactopeptone as a nitrogen source were 1% against MNNG and 1.5% against NQO. Optimal pH of the medium, culture temperature, and shaking speed for the antimutagenic substance(s) production were pH 7.0, $37^{\circ}C$ and 150 rpm, respectively. Under the optimal condition, the antimutagenic effects of L. plantarum KLAB21 culture supernatant were 98.4% against MNNG on S. typhimurium TA100 and 57.3% against NQO on S. typhimurium TA98.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.5
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• pp.423-431
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• 2021

Purpose: To assess the effect of combination probiotic Saccharomyces boulardii CNCM-I 3799 and Bacillus subtilis CU-1 in outpatient management of acute watery diarrhea in children. Methods: A randomized double-blind placebo-controlled study was conducted in 180 participants aged six months to five years with acute mild to moderate diarrhea. All were enrolled from six centers across India and centrally randomized to receive S. boulardii CNCM-I 3799 and B. subtilis CU-1 or a placebo along with oral rehydration salts and zinc supplementation. Each participant was followed up for three months to assess recurrence of diarrhea. Results: The mean duration of diarrhea in the probiotic and placebo groups were 54.16 hours and 59.48 hours, respectively. The difference in the duration of diarrhea in those administered with probiotic or placebo within 24 hours of diarrhea onset was 25.21 hours. Furthermore, the difference in duration of diarrhea was 13.84 hours (p<0.05) for participants who were administered with probiotics within 48 hours. There were no significant differences in the stool frequencies between the two arms. After three months, 15% in the probiotic group and 18.5% in the placebo group reported episodes of diarrhea. The mean duration of diarrhea was considerably lower in the probiotic group, 31.02 hours versus 48 hours in placebo (p=0.017). Conclusion: S. boulardii CNCM-I 3799 and B. subtilis CU-1 combination was effective in reducing the duration of diarrhea when administered within 48 hours of diarrhea onset. Similarly, it reduced recurrence of diarrhea and its intensity in the subsequent three months.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.540-549
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• 2021

The Wnt/β-catenin signaling pathway is involved in breast cancer and Myxococcus fulvus KYC4048 is a myxobacterial strain that can produce a variety of bioactive secondary metabolites. Although a previous study revealed that KYC4048 metabolites exhibit anti-proliferative effects on breast cancer, the biochemical mechanism involved in their effects remains unclear. In the present study, KYC4048 metabolites were separated into polar and non-polar (ethyl acetate and n-hexane) fractions via liquid-liquid extraction. The effects of these polar and non-polar KYC4048 metabolites on the viability of breast cancer cells were then determined by MTT assay. Expression levels of Wnt/β-catenin pathway proteins were determined by Western blot analysis. Cell cycle and apoptosis were measured via fluorescence-activated cell sorting (FACS). The results revealed that non-polar KYC4048 metabolites induced cell death of breast cancer cells and decreased expression levels of WNT2B, β-catenin, and Wnt target genes (c-Myc and cyclin D1). Moreover, the n-hexane fraction of non-polar KYC4048 metabolites was found most effective in inducing apoptosis, necrosis, and cell cycle arrest, leading us to conclude that it can induce apoptosis of breast cancer cells through the Wnt/β-catenin pathway. These findings provide evidence that the n-hexane fraction of non-polar KYC4048 metabolites can be developed as a potential therapeutic agent for breast cancer via inhibition of the Wnt/β-catenin pathway.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.57-70
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• 2018

In this study, verification of the nonlinear effective stress analysis is performed for introducing performance based earthquake resistance design of port and harbor structures. Seismic response of gravitational caisson quay wall in numerical analysis is compared directly with dynamic centrifuge test results in prototype scale. Inside of the rigid box, model of the gravitational quay wall is placed above the saturated sand layer which can show the increase of excess pore water pressure. The model represents caisson quay wall with a height of 10 m, width of 6 m under centrifugal acceleration of 60 g. The numerical model is made in the same dimension with the prototype scale of the test in two dimensional plane strain condition. Byrne's liquefaction model is adopted together with a nonlinear constitutive model. Interface element is used for sliding and tensional separation between quay wall and the adjacent soils. Verification results show good agreement for permanent displacement of the quay wall, horizontal acceleration at quay wall and soil layer, and excess pore water pressure increment beneath the quay wall foundation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.143-149
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• 2019

In this study, a U-shape composite beam was developed to be effectively used for a steel parking lot which is 8m or lower in height. When the U-shape composite beam was applied to a steel parking lot, essential considerations were story-height and long-span. In addition, due to the mixed structural system with reinforced concrete and steel material, the U-shape composite beam needed to have a structural integrity and reliable performance over demand capacity. The main objective of this study was to investigate the performance of the structure consisting of the reinforced concrete (RC) slab and U-shape beam. A U-shape composite beam generally used at a parking lot served as a control specimen. Four specimens were tested under four-point bending. To calculate theoretical values, strain gauges were attached to rebar, steel plate, and concrete surface in the middle of the specimens. As the results, initial yielding strength of the control specimen occurred at the bottom of the U-shaped steel. After yielding, the specimen reached the maximum strength and the RC slab concrete was finally failed by concrete crush due to compressive stress. The structural performance such as flexural strength and ductility of the specimen with the increased beam depth was significantly improved in comparison with the control specimen. Furthermore, the design of the U-shape composite beam with the consideration of flexural strength and ductility was effective since the structural performance by a negative loading was relatively decreased but the ductile behavior was evidently improved.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.3
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• pp.165-170
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• 2019

The purpose of this study was to analyze the effectiveness of different storage periods of lactic acid bacteria (LAB)-fermented low moisture fresh rice straw silage. The low moisture fresh rice straw sample was inculcated with LAB and stored for different storage periods such as 45, 90, and 365 days, respectively. The low moisture fresh rice straw (LMFRS) silage inoculated with LAB exhibited reduction in pH throughout the fermentation as compared with the control (P<0.05). The lactic acid content was increased at the late fermentation period (90 and 365 days, respectively) in LAB inoculated LMFRS silage as compared with the control (P<0.05). In contrast, the acetic acid and butyric acid concentrations were slightly reduced in the LAB inoculated LMFRS silage sample at 90 and 365 days fermentation, respectively. Meanwhile, the non-inoculated LMFRS silage showed higher amounts of acetic acid and butyric acid at an extended fermentation with low bacterial population as compared with the LAB inoculated LMFRS silage. However, lactic acid concentration was slightly high in the non-inoculated LMFRS silage at early 45 days fermentation. Additionally, the nutrient profile such as crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF), and total digestibility nutrients (TDN) were not significantly different in control and LAB inculcated samples during all fermentation. Though, the microbial population was greater in the LAB inoculated LMFRS silage as compared with the control. However, the massive population was noted in the LAB inoculated LMFRS silage during all fermentation. It indicates that the inoculated LAB is the main reason for increasing fermentation quality in the sample through pH reduction by organic acids production. Overall results suggest that the LAB inoculums are the effective strain that could be a suitable for LMFRS silage fermentation at prolonged days.

• Korean Journal of Veterinary Service
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• v.44 no.2
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• pp.73-83
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• 2021

Although many swine farms continuously vaccinated to sow to prevent Porcine epidemic diarrhea(PED), PED has occurred annually in swine herds in Jeonbuk province, Korea. In the present study, the small intestine and feces samples from 17 farms where severe watery diarrhea and death of newborn piglets occurred in 2019 were collected, amplified by RT-PCR and determined the complete nucleotide sequences of the spike (S) glycoprotein genes of nine Jeonbuk PEDV isolates. The spike (S) glycoprotein is an important determinant for molecular characterization and genetic relationship of PEDV. These nine complete S gene isolates were compared with other PEDV reference strains to identify the molecular diversity, phylogenetic relationships and antigenicity analysis. 9 field strains share 98.5~100% homologies with each other at the nucleotide sequence level and 97.3~100% homologies with each other at the amino acid level. The nine Jeonbuk PEDV isolates were classified into G2b group including a genetic specific signal, S-indels (insertion and deletion of S gene). In addition, comparisons the neutralizing epitopes of S gene between 9 field strains and domestic vaccine strains of Korea mutated 12-15 amino acids with SM-98-1 (G1a group) and mutated 0-3 amino acids with QIAP1401 (G2b group). Therefore, the development of G2b-based live vaccines will have to be expedited to ensure effective prevention of endemic PED in Korea. In addition, we will need to be prepared with periodic updates of preventive vaccines based on the PEDV variants for the re-emergence of a virulent strain.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.73-80
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• 2022

This study evaluated changes in fluidity and rheological properties over time for 3D printed composite materials, and evaluated compressive strength and splitting tensile strength properties for laminated and molded specimens. The composite material for 3D printing starts to change rapidly after 30 minutes of extrusion, and the viscosity of the material tends to be maintained up to 90 minutes, but it was confirmed that construction within 60 minutes after mixing is effective. The compressive strength of the laminated test specimen showed equivalent or better performance at all ages compared to the molded test specimen. In the stress-strain curve of the laminated specimen, the initial slope was similar to that of the molded specimen, but the descending slope was on average 1.9 times higher than that of the molded specimen, indicating relatively brittle behavior. The splitting tensile strength of the P-V laminated specimen was about 6% lower than that of the molded specimen. It is judged that this is because the interfacial adhesion force against the vertical load is affected by the pattern direction of the laminated test specimen.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.103-110
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• 2022

The purpose of this study is to experimentally evaluate the stiffness and strength reduction according to the reinforcing bar details of the vertically divided reinforced concrete shear walls. To confirm the effect of reducing strength and stiffness according to vertical division, four real-scale specimens were fabricated and repeated lateral loading tests were performed. As a result of the experiment, it was confirmed that the strength and stiffness were decreased according to the vertical division. In particular, as the stiffness reduction rate is greater than the strength reduction rate, it is expected that safety against extreme strength can be secured when the load is redistributed according to vertical division. As a result of checking the crack pattern, a diagonal crack occurred in the wall subjected to compression control among the divided walls. It was confirmed that two neutral axes occurred after division, and the reversed strain distribution appeared in the upper part, showing the double curvature pattern. In future studies, it is necessary to evaluate the stiffness reduction rate considering the effective height of the wall, to evaluate additional variables such as wall aspect ratio, and to conduct analytical studies on various walls using finite element analysis.