• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.82-87
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• 2016

Enterotoxigenic Bacteroides fragilis (ETBF) produces enterotoxins known to be a virulence factor. Three isotypes of the B. fragilis toxin (BFT) gene have been identified: bft-1, bft-2, and bft-3. We investigated the presence of bft isotypes in clinical B. fragilis isolates and the antimicrobial resistance of BFT-negative and BFT-positive isolates. Overall, 537 B. fragilis isolates were collected from extraintestinal specimens over 8 years (2006~2013) from a university hospital in Korea. Samples were analyzed by multiplex PCR to identify the bft gene isotypes. Additionally, the antimicrobial susceptibility of 107 B. fragilis isolates (74 BFT-negative and 33 BFT-positive) was examined by the CLSI agar dilution method. PCR revealed a total bft gene detection rate of 30%, while 33% and 29% of blood and other extraintestinal isolates contained the gene, respectively. Among ETBF isolates, the most common isotype was bft-1 gene, followed by bft-2 and bft-3 (bft-1 77%, bft-2 14%, bft-3 9%). Resistance rates (%) for BFT-negative and positive isolates differed in response to various antimicrobial agents, with 3%, 5%, 1% and 38% of BFT-negative isolates and 3%, 6%, 3% an 42% of BFT-positive isolates being resistant to piperacillin-tazobactam, cefoxitin, imipenem, and clindamycin, respectively. Interestingly, neither BFT-negative nor positive isolates showed antimicrobial resistance to chloramphenicol and metronidazole. Overall, the proportion of ETBF from blood was similar to that of other extraintestinal sites and the bft-1 gene was the predominant isotype. Higher antimicrobial resistance rates were found in BFT-positive isolates than BFT-negative isolates, but these differences were not statistically significant.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.89-95
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• 2020

In this paper, we present Beamforming (BF) Training (BFT) for asymmetric links in IEEE 802.11ay. IEEE 802.11ay introduced BFT for asymmetric links that aims to increase the BFT success probability for Station (STA) with insufficient link budget to communicate with an Access Point (AP). BFT for asymmetric links utilizes directional BFT allocation to avoid the usage of quasi-omni pattern at the AP side, and thus to increase STA's BFT success rate. However, there are no publicly available simulation tools supporting IEEE 802.11ay. For these reasons, we present in this paper an implementation of BFT for asymmetric links in ns-3 with its novel techniques such as Training RX (TRN-R) subfield and BFT allocation. We then evaluate by simulation the performance of BFT for asymmetric links.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.418-425
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• 2021

The effects of an aquaponic system based on biofloc technology (BFT-AP) were analyzed for eel Anguilla japonica as aquaculture species and caipira Lactuca sativa as the cultivated crops. The rate of weight gain rate by the eels was 178% (BFT-AP 200 head) > 136% (BFT-AP 100 head) > 100% (BFT). The eel body weight in the BFT-AP (200 head) significantly increased when compared to the BFT only eel group (P<0.05). The weight of the upper layer of caipira was 91±8.5 g (200 head) > 90±8.9 g (100 head) > 48±8.3 g (Hydroponic crop, HP). The crop growth in all BFT-AP groups was higher than the control, the hydroponic group. The total ammonia nitrogen (TAN) and NO₂^--N concentrations decreased in the BFT-AP group when compared to the BFT group. It was possible to remove nitric acid from the aquaponics system and reuse it as eel rearing water. Although some nutrient concentrations were low in BFT when compared to HP, the nutrient concentration was sufficient for plant growth. The results show that BFT has the potentially to provide a sustainable aquaponic system.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.196-204
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• 2022

This study observed changes in survival, growth performance and water quality for 90 days to confirm the possibility of Leiocassis ussuriensis farming using Biofloc technology (BFT) using Bacillus subtilis. Feed and molasses were added to the experimental tank to produce BFT water before planting the experiment, and B. subtilis was inoculated to stabilize the water quality for 40 days. The survival rate of the experimental fish was 92.7±3.2% in the control group and 95.8±3.3% in the BFT group. The Weight gain (WG) was 118.1±9.0% of the control and 197.7±15.6% of the BFT, and the Specific growth rate (SGR) was 0.87±0.5% of the control and 1.21±0.06% of the BFT. As for the feed efficiency, the control was 43.7±2.6% and the BFT was measured at 70.1±4.1%, indicating that the feed efficiency of the BFT was higher. As a result of measuring the water quality change during the experimental period, pH was reduced in both the control and the BFT, and Mixed Liquor Suspended Solids (MLSS) did not show any change in the control, but the BFT showed a significant increase at 90 days. NH₄⁺-N and NO₂^--N showed a significant increase from the 30 days of the experiment in the control, but showed no change in the BFT. In conclusion, as a result of applying the BFT system using B. subtilis to the process of cultivating Leiocassis ussuriensis, the water quality tended to stabilize, and the growth rate and feed efficiency were found to be higher than those of the control, confirmiWng that it had a positive effect.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5A
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• pp.389-397
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• 2011

In this study, an experiment for the biaxial behavior of specimens was carried out to identify whether the isotropic flexure tensile stress of concrete in the BFT method is feasible. Another experiment for the improvement of the BFT method was conducted to ensure the isotropic flexure tensile stress of BFT specimens during the test. In addition, the biaxial flexure strength of concrete given by the improved BFT method was compared to the uniaxial flexure strength by the four-point bending test. Test results show that the isotropic flexure tensile stress of concrete using the BFT method was highly influenced by the surface conditions and warping of the specimens. Using improved BFT method, we could obtained the isotropic flexure tensile stress of concretes. The biaxial flexure strength of BFT was about 32% greater than the uniaxial flexure strength of the four-point bending test. In the experiment, with the smaller scatter, the improved BFT method gave a reliable biaxial flexure strength like the four-point bending test.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.479-486
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• 2011

In this study, we conducted experiment and finite element analysis on the flexural behavior of the round concrete panels according to the evaluation method of biaxial flexural tensile strengths. The Round Panel Test (RPT) and the Biaxial Flexure Test (BFT) were used to determine the biaxial flexural strength of round plain concrete panels. In order to understand the stress distribution on the panels, we measured load-strain relationship at the center of the panels' bottom surface. Test results show that fracture pattern in RPT and BFT panels are similar, and the tensile stress distribution is uniform in all directions at the center of the bottom surface of the panels for both RPT and BFT. The distribution of stresses in two test specimens coincided with the analysis result. The average biaxial flexural strength of RPT is about 29% greater than those of the BFT. The coefficient of variations (COV) of the RPT and BFT for the biaxial flexure strength is 8%, 6%, respectively, which indicates that BFT method is useful and reliable for determining biaxial flexural strengths of the concrete.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.305-308
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• 2003

We earlier reported the identification of bif-k, t-3, and a third ORF from an enterotoxigenic strain of Bacteroides fragilis 419, which was isolated from the blood of a Korean patient suffering from systemic infections. In the present study, the deleted fragments of the t-3 and the bft-k genes from B. fragilis 419 were cloned into suicide vector PJST55 and used to create a mutant with chromosomal disruption of the t-3 and bft-k genes. Structures of the selected mutants, DMP-2 and DBT-4, were found to be intermediate forms that integrated the suicide vector into the chromosome. t-3 disrupted Dmp-2 and Bft-k disrupted DBT-4 did not react with polyclonal antibodies against T-3 or BFT-K, and had no biological activity in $HT29/C_1$, cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.378-387
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• 2017

This study was performed to isolate bacteria that could control the nitrite levels in a biofloc technology (BFT) culture tank. Nitrite-eliminating bacteria were isolated from a BFT culture tank rearing goldfish, and the isolated bacterium exhibiting the most potent nitrite eliminating ability was labeled as the "NOBSB1" strain. Sequencing the 16S rRNA revealed that NOBSB1 is a species in the genera Bosea. NOBSB1 had the following characteristics with regard to nitrite removal: (1) it removed nitrite by functioning heterotrophically in the presence of a carbon source (sugars); (2) it eliminated nitrite most effectively within a temperature range of $20-30^{\circ}C$, but its activity decreased at temperatures above $35^{\circ}C$ and below $20^{\circ}C$; (3) it had optimum nitrite removal ability within a pH range of 6.0-8.0; (4) it removed nitrite more effectively under hypoxic than aerobic conditions. NOBSB1 inoculation did not decrease ammonia or nitrate levels, but eliminated nitrite in a BFT culture tank rearing common carp (Cyprinus carpio). After inoculating the NOBSB1 strain in a BFT culture tank, NOBSB1 controlled and sufficiently reduced the nitrite concentration in the tank.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.41-46
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• 2019

Recently, the Byzantine Fault Tolerance(BFT) family of consensus algorithms has been attracting attention as the problems of the Proof-of-work (PoW) blockchain consensus algorithms result in energy waste and lack of scalability. One of the great features of the PBFT family consensus algorithms is the formation of a set of validators and consensus within them. In this paper, we compared and analyzed the scalability, targeted attackability, and civil attackability of Algorand, Stellar, and EOS validator set formation methods among BFT family consensus algorithms. Also, we found the problems of each verifier formation method through data analysis, and the consensus algorithms showed that the centralization phenomenon that the few powerful nodes dominate the whole system in common.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1081-1085
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• 2017

Objective: Previously, we reported quantitative trait loci (QTLs) affecting backfat thickness (BFT) traits on pig chromosome 5 (SW1482-SW963) in an F2 intercross population between Landrace and Korean native pigs. The aim of this study was to evaluate glutamate receptor-interacting protein 1 (GRIP1) as a positional candidate gene underlying the QTL affecting BFT traits. Methods: Genotype and phenotype analyses were performed using the 1,105 $F_2$ progeny. A mixed-effect linear model was used to access association between these single nucleotide polymorphism (SNP) markers and the BFT traits in the $F_2$ intercross population. Results: Highly significant associations of two informative SNPs (c.2442 T>C, c.3316 C>G [R1106G]) in GRIP1 with BFT traits were detected. In addition, the two SNPs were used to construct haplotypes that were also highly associated with the BFT traits. Conclusion: The SNPs and haplotypes of the GRIP1 gene determined in this study can contribute to understand the genetic structure of BFT traits in pigs.