• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.250-258
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• 2021

Among various species of marine bacteria, those belonging to the genus Halomonas have several promising applications and have been studied well. However, not much information has been available on their antibiotic resistance. In our efforts to learn about the antibiotic resistance of strain Halomonas socia CKY01, which showed production of various hydrolases and growth promotion by osmolytes in previous study, we found that it exhibited resistance to multiple antibiotics including kanamycin, ampicillin, oxacillin, carbenicillin, gentamicin, apramycin, tetracycline, and spectinomycin. However, the H. socia CKY01 resistance pattern to kanamycin, gentamicin, apramycin, tetracycline, and spectinomycin differed in the presence of 10% NaCl and 1% NaCl in the culture medium. To determine the mechanism underlying this NaCl concentration-dependent antibiotic resistance, we compared four aminoglycoside resistance genes under different salt conditions while also performing time-dependent reverse transcription PCR. We found that the aph2 gene encoding aminoglycoside phosphotransferase showed increased expression under the 10% rather than 1% NaCl conditions. When these genes were overexpressed in an Escherichia coli strain, pETDuet-1::aph2 showed a smaller inhibition zone in the presence of kanamycin, gentamicin, and apramycin than the respective control, suggesting aph2 was involved in aminoglycoside resistance. Our results demonstrated a more direct link between NaCl and aminoglycoside resistance exhibited by the H. socia CKY01 strain.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.293-298
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• 1993

The ppage resistance mechanism of Lactococcus lactis subsp. cremoris ATCC 11602-A1 was investigated. When parent and A1 were incubated at 30 and 40$^{\circ}C$, A1 grew well and multiplication of phage(MOI=1)on A1 slightly occurred at 40$^{\circ}C$ in contrast with parent. There was a great difference of proteolytic activity between parent and A1, irrespective of the temperature. As a result of ADS treatment oon culture broth, survival rate of A1 was 27% at the lethal concentration of parent and adsorption rate of phage was increased to 95~97%, which was considered to come from the exposure of phage receptor site masked by an unknown component. These results suggest that acridine orange (AO) treatment leads to the modification of cell wall, conferring resistance to high temperature and lytic phage. No change in plasmid profiles of A1 at 30 and 40$^{\circ}C$ were found, which suggests that plasmid is not relative to temperature-resistance of A1.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9853-9857
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• 2014

Background: The morbidity and mortality rate of liver cancer continues to rise in China and advanced cases respond poorly to chemotherapy. Ribosomal protein L24 has been reported to be a potential therapeutic target whose depletion or acetylation inhibits polysome assembly and cell growth of cancer. Materials and Methods: Total RNA of cultured amycin-resistant and susceptible HepG2 cells was isolated, and real time quantitative RT-PCR were used to indicate differences between amycin-resistant and susceptible strains of HepG2 cells. Viability assays were used to determine amycin resistance in RPL24 transfected and control vector and null-transfected HepG2 cell lines. Results: The ribosomal protein L24 transcription level was 7.7 times higher in the drug-resistant HepG2 cells as compared to susceptible cells on quantitative RT-PCR analysis. This was associated with enhanced drug resistance as determined by methyl tritiated thymidine (3H-TdR) incorporation. Conclusions: The ribosomal protein L24 gene may have effects on drug resistance mechanisms in hepatocellular carcinoma HepG2 cells.

• Korean Journal of Materials Research
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• v.12 no.6
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• pp.436-441
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• 2002

Effect of Sn addition on the stress corrosion cracking(SCC) resistance of the Al-Cu-Mn cast alley was investigated by C-ring teat and electrical conductivity measurement, The electrical conductivity and SCC resistance increased by Sn addition. The alley containing 0,10%Sn showed maximum electrical conductivity and the best SCC resistance. At the same composition, the electrical conductivity and SCC resistance increased from peak aged condition to ever aged condition. The PFZ and coarse precipitates along the grain boundary were observed from TEM micrographs. The fracture mode of the alloy was confirmed as intergranular type and showed brittle fracture surface. The SCC mechanism of the alloy was concluded as the anodic dissolution model, The maximum hardness was increased from 130Hv in the Sn-free alloy to 156Hv in the 0.10%Sn added alloy.

• Biomolecules & Therapeutics
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• v.26 no.3
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• pp.313-321
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• 2018

Anti-cancer drug resistance is a major problem in colorectal cancer (CRC) research. Although several studies have revealed the mechanism of cancer drug resistance, molecular targets for chemotherapeutic combinations remain elusive. To address this issue, we focused on the expression of cellular prion protein ($PrP^C$) in 5-FU-resistant CRC cells. In 5-FU-resistant CRC cells, $PrP^C$ expression is significantly increased, compared with that in normal CRC cells. In the presence of 5-FU, $PrP^C$ increased CRC cell survival and proliferation by maintaining the activation of the PI3K-Akt signaling pathway and the expression of cell cycle-associated proteins, including cyclin E, CDK2, cyclin D1, and CDK4. In addition, $PrP^C$ inhibited the activation of the stress-associated proteins p38, JNK, and p53. Moreover, after treatment of 5-FU-resistant CRC cells with 5-FU, silencing of $PrP^C$ triggered apoptosis via the activation of caspase-3. These results indicate that $PrP^C$ plays a key role in CRC drug resistance. The novel strategy of combining chemotherapy with $PrP^C$ targeting may yield efficacious treatments of colorectal cancer.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.841-849
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• 2018

The purpose of a rock bolt is to improve the mechanical performance of a jointed-rock mass. The performance of a rock bolt is generally evaluated by conducting a field pullout test, as the analytical or numerical evaluation of the rock bolt behavior still remains difficult. In this study, wide range of field test was performed to investigate the pullout resistance of rock bolts considering influencing factors such as the rock type, water bearing conditions, rock bolt type and length. The test results showed that the fully grouted rock bolt (FGR) in water-bearing rocks can be inadequate to provide the required pullout resistance, meanwhile the inflated steel tube rock bolt (ISR) satisfied required pullout resistance, even immediately after installation in water-bearing conditions. The ISR was particularly effective when the water inflow into a drill hole is greater than 1.0 l/min. The effect of the rock bolt failure on the tunnel stability was investigated through numerical analysis. The results show that the contribution of the rock bolt to the overall stability of the tunnel was not significant. However, it is found that the rock bolt can effectively reinforce the jointed-rock mass and reduce the possibility of local collapses of rocks, thus the importance of the rock bolt should not be overlooked, regardless of the overall stability.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.330-333
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• 2003

Recently electrokinetic process is known to be a promising remediation technology for the contaminated soils with heavy metals, radionuclides, organic matters, and so on. The contaminants in electrokinetic technology are removed mainly by three mechanisms; electroosmosis, electromigration, and electrophoresis. When direct current is introduced between two electrodes planted in soil, a large amount of hydrogen ions is formed and moves from anode to cathode with the other cations contained in electrolyte. The water flow caused by tile movement of cations is called as electroosmosis. Especially for non-ionic pollutants, the electroosmotic flow(EOF) is the most important removal mechanism among them and transports contaminants from anode to cathode along the water flow. In this study, characteristics of electroosmotic flow was investigated according to the resistance state of soil. The decrease, maintenance, and increase of soil resistance could be obtained by controlling ions in soil. When the resistance of soil was decreasing or maintained, the EOF is proportional to electric current and voltage, respectively and when the resistance was increasing, the EOF is proportional to only electric current not voltage.

• 연구논문집
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• s.25
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• pp.193-205
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• 1995

Plasma spray coating technology is essential for the microsemiconductor processes based on the electronic and computer industry, and extend gradually the range of application for up-to-date industry such as diesel engine and gas turbine components. These thechonoogies may be applied to the components requiring wear-resistance, heat resistance, fatigue-resistance, and corrosion-resistance. In this research, plasma spray technology was selected for the wear resistant coatings as the most proper technique. The final goal of this study is to improve the wear resistance through establishment of coating soft-ware, and basic research for industrialization of the technology concerned.

• Mycobiology
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• v.29 no.1
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• pp.48-53
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• 2001

Plants have the ability to acquire an enhanced level of resistance to pathogen attack after being exposed to specific biotic stimuli. To obtain plant growth-promoting rhizobacteria inducing resistance against cucumber anthracnose by Colletotrichum orbiculare, more than 800 strains of rhizobacteria were screened in the greenhouse. Among these strains, Bacillus amyloliquefaciens solate EXTN-1 showed significant disease control efficacy on the plants. Induction of pathogenesis-related(PR-la) gene expression by EXTN-1 was assessed using tobacco plants transformed with PR-1a::$\beta$-glucuronidase(GUS) construct. GUS activities of tobacco treated with EXTN-1 and salicylic acid-treated transgenic tobacco were significantly higher than those of tobacco plants with other treatments. Gene expression analyses indicated that EXTN-1 induces the accumulation of defense-related genes of tobacco. The results showed that some defense genes are expressed by the treatment with EXTN-1 suggesting the similar resistance mechanism by salicylic acid.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.151-154
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• 2007

To build up the green roofs, it must not adverse effect to durability and structural safety. That is conducted by safety system which consist of waterproofing to form basically, root barrier to protect the waterproofing. The reason why root barrier form is to protect the penetration force of root growth and the root could penetrate concrete surface, move inward so far. It may cause shorten the life span on concrete structure. For this problem, government constantly demand the solution to form the root barrier for waterproofing and concrete structure before the building is service. However, the technical action is not fully prepared. Therefore, in this study, we would like to suggest the workability and suitability of the copper plate to solve not only the side of waterproofing but also root barrier for green roof system and exhibit the mechanism for root penetration resistance and corrosion resistance.