• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.241-246
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• 2007

The capacity of a lateral load resistance of a joint with Jangbu-connection of Dori-directional frame in traditional wood structure system was studied, through experiments of 1/2 scaled and T-shaped 7 subassemblies of joint of Dori-directional frame for Deawoongjeon of Bongjungsa. From the experiment, it was shown that the capacity of a lateral load resistance was influenced by the vertical load confining joint and not influenced by the number of Chok and the depth of Changbang, And lateral load resistance mechanism is developed by the restraint between the vertical load and the contacting edge of column; if structure is pushed to the left, the top-right end of Pyeongju contacts with Changbang and left Changbang loses the contacts with Pyeongju and therefore only right Changbang can resist to lateral load.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.353-358
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• 1996

E. coli 11 and E. coli 101, clinical isolates of Escherichia coli were resistant to various quinolones, especially MICs to norfloxacin of both strains were higher than 100 mg/ml. In the presence of carbonyl cyanide m-chlorophenylhydrazone, a proton gradient uncoupler, norfloxacin uptake in both strains was increased, suggesting that an efflux system play an important role in the norfloxacin resistance. Outer membrane proteins of the susceptible and resistant strains which could affect the route of norfloxacin entry into cells were different. When quinolone resistance determining region(QRDR) of gyrA was amplified using PCR and cut with Hinf I, QRDR in the susceptible strain yielded two fragments while QRDRs in E. coli 11 and E. coli 101 yielded only one uncut fragment. When DNA sequence of QRDR was analyzed, there were two mutations as Ser-83 and Asp-87 in both resistant strains. these residues were changed to Leu-83 and Asn-87, respectively. These results showed that the norfloxacin resistance of E. coli 11 and E. coli 101 was resulted from multiple changes-an altered DNA gyrase A subunit, a change in route of drug entry, and reduction in quinolone concentration inside cells due to an efflux system.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.224-230
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• 2012

Thermal batteries have excellent mechanical robustness, reliability, and long shelf life. Due to these characteristics as well as their unique activation mechanism, thermal batteries are widely adopted as military power sources. Li(Si)/$FeS_2$ thermal batteries, which are used mostly in these days, use LiCl-KCl and LiBr-LiCl-LiF as molten salt electrolyte. However, it is known that Li(Si)/$FeS_2$ thermal batteries have high internal resistance. Especially, $FeS_2$ cathode accounts for the greater part of internal resistance in unit cell. Many efforts have been put into to decrease the internal resistance of thermal batteries, which result in the development of new electrode material and new electrode manufacturing processes. But the applications of these new materials and processes are in some cases very expensive and need complicated additional processes. In this study, internal resistance study was conducted by adding carbon black and carbon nano-tube, which has high electron conductivity, into the $FeS_2$ cathode. As a results, it was found that the decrease of internal resistance of $FeS_2$ cathode by the addition of carbon black and carbon nano-tube.

• Korean Journal of Metals and Materials
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• v.46 no.11
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• pp.725-729
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• 2008

Deposition characteristics of electroless plated Ni-W-P films were investigated for various complexing agents. Used complexing agents are sodium citrate, sodium gluconate and sodium malonate. In this study, the existing mixed potential theory could explain the overall mechanism of Ni-W-P electroless plating for all complexing agents. The deposition rate could be also expected by the theory. The deposited Ni-W-P films were evaluated in term of surface hardness and corrosion resistance. Microhardness of the deposit increased about 1,000 Hv after heat treatment for one hour at $400^{\circ}C$, because it was above the crystallization temperature of $Ni_3P$. The deposited Ni-W-P films can exhibit excellent corrosion resistance in using sodium malonate as a complexing agent, the other hand the using sodium gluconate was the worst corrosion resistance. The worst corrosion resistance was due to a large number of nano-sized pin-holes or small pores. The plating current at the mixed potential increases when the using sodium malonate as a complexing agent, it was explained by the cross section.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.153-160
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• 1992

The doxorubicin resistance locus from Streptomyces peucetius subsp. caesius (the doxorubicin producer, ATCC 27952) has been cloned. The sequence data over 4.4 kb regions reveals the presence of four possible open reading frames (ORFs). ORF2 and ORF3 would encode proteins containing 329 and 283 amino acids, respectively. The protein encoded by ORF2 has two almost identical ATP binding domains with p-glycoprotein, the product of a multidrug resistance gene from tumor cells, and that encoded by ORF3 has several hydrophobic domains suggesting that it is located in the bacterial membrane. These two remarkable similarities of the gene product to p-glycoprotein of mammalian tumor cells suggest that the two proteins may enable bacteria to extrude a variety of toxic agents, including daunorubicin and doxorubicin, by an ATP dependent efflux mechanism analogous to the multidurg resistance protein of cancer cells.

• Computers and Concrete
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• v.31 no.6
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• pp.469-484
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• 2023

The response mechanism of simply supported two-way reinforced concrete (RC) slabs under fire was numerically studied from the view of stress redistribution using the finite element software ABAQUS. Results show that: (1) Simply supported two-way RC slabs undergo intense stress redistribution, and their responses show four stages, namely elastic, elastic-plastic, plastic and tensile membrane stages. There is no cracking in the fire area of the slabs until the tensile membrane stage. (2) The inverted arch effect and tensile membrane effect improve the fire resistance of the two-way slabs. When the deflection is L/20, the slab is in an inverted arch effect state, and the slab still has a good deflection reserve. The deformation rate of the slab in the tensile membrane stage is smaller than that in the elastic-plastic and plastic stages. (3) Fire resistance of square slabs is better than that of rectangular slabs. Besides, increasing the reinforcement ratio or slab thickness improves the fire resistance of the slabs. However, an increase of cover thickness has little effect on the fire resistance of two-way slabs. (4) Compared with one-way slabs, the time for two-way slabs to enter the plastic and tensile cracking stage is postponed, and the deformation rate in the plastic and tensile cracking stage is also slowed down. (5) The simply supported two-way RC slabs can satisfy with the requirements of a class I fire resistance rating of 90 min without additional fire protection.

• Biomolecules & Therapeutics
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• v.21 no.2
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• pp.114-120
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• 2013

Most patients with mutant B-Raf melanomas respond to inhibitors of oncogenic B-Raf but resistance eventually emerges. To better understand the mechanisms that determine the long-term responses of mutant B-Raf melanoma cells to B-Raf inhibitor, we used chronic selection to establish B-Raf (V600E) melanoma clones with acquired resistance to the new oncogenic B-Raf inhibitor UI-152. Whereas the parental A375P cells were highly sensitive to UI-152 ($IC_{50}$ < $0.5{\mu}M$), the resistant sub-line (A375P/Mdr) displayed strong resistance to UI-152 ($IC_{50}$ < $20{\mu}M$). Immunofluorescence analysis indicated the absence of an increase in the levels of P-glycoprotein multidrug resistance (MDR) transporter in A375P/Mdr cells, suggesting that resistance was not attributable to P-glycoprotein overexpression. In UI-152-sensitive A375P cells, the anti-proliferative activity of UI-152 appeared to be due to cell-cycle arrest at $G_0/G_1$ with the induction of apoptosis. However, we found that A375P/Mdr cells were resistant to the apoptosis induced by UI-152. Interestingly, UI-152 preferentially induced autophagy in A375P/Mdr cells but not in A375P cells, as determined by GFP-LC3 puncta/cell counts. Further, autophagy inhibition with 3-methyladenine (3-MA) partially augmented growth inhibition of A375P/Mdr cells by UI-152, which implies that a high level of autophagy may protect UI-152-treated cells from undergoing growth inhibition. Together, our data implicate high rates of autophagy as a key mechanism of acquired resistance to the oncogenic B-Raf inhibitor, in support of clinical studies in which combination therapy with autophagy targeted drugs is being designed to overcome resistance.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.25-33
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• 2012

The association of verotoxic E. coli and Acinetobacter spp. with various antibiotic-resistant, diarrhogenic, and nosocomial infections has been a cause for concern worldwide. E. coli and A. haemolyticus isolated on a number of selective media were screened for virulence factors, antibiotic resistance, and transformation of resistance genes. Out of 69 E. coli isolates obtained, 25 (35.23%), 14 (20.30%), and 28 (40.58%) were positive for Vtx1&2, Vtx1, and Vtx2, respectively, 49 (71.015%) for extendedspectrum beta-lactamases (ESBLs), 34 (49.28%) for serum resistance, 57 (82.61%) for cell surface hydrophobicity, 48 (69.57%) for gelatinase production, and 37 (53.62%) for hemolysin production. For the 14 A. haemolyticus isolates, only 2 (14.29%) in each case from all the samples investigated were positive for Vtx1, Vtx2 and Vtx1&2 respectively, 8 (57.14%) for ESBLs, 7 (50.00%) for serum resistance, 11 (78.57%) for cell surface hydrophobicity, 4 (28.57%) for gelatinase production, and 8 (57.14%) for hemolysin production. Although transformation occurred among the E. coli and Acinetobacter isolates (transformation frequency: $13.3{\times}10^{-7}-53.4^{-7}$), there was poor curing of the plasmid genes, a confirmation of the presence of stable antibiotic-resistant genes (DNA concentration between 42.7 and 123.8 ${\mu}g$) and intragenetic transfer of multidrug-resistant genes among the isolates. The isolates were potentially virulent and contained potentially transferable antibiotic resistance genes. Detection of virulence factors, antibiotic resistance genes, and transformation among these isolates is a very significant outcome that will influence approaches to proactive preventive and control measures and future investigations. However, continued surveillance for drug resistance among these bacteria and further investigation of the mechanism of action of their virulence factors are a necessity.

• Research in Plant Disease
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• v.27 no.4
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• pp.137-148
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• 2021

Plant RNA viruses are one of the most destructive pathogens that cause a significant loss in crop production worldwide. They have evolved with high genetic diversity and adaptability due to the short replication cycle and high mutation rate during genome replication, which are characteristics of RNA viruses. Plant RNA viruses exist as quasispecies with high genetic diversity; thereby, a rapid population transition with new fitness can occur due to selective pressure resulting from environmental changes. Plant resistance can act as selective pressure and affect the fitness of the virus, which may lead to the emergence of resistance-breaking variants. In this paper, we introduced the evolutionary perspectives of plant RNA viruses and the driving forces in their evolution. Based on this, we discussed the mechanism of the emergence of variant viruses that overcome plant resistance. In addition, strategies for deploying plant resistance to viral diseases and improving resistance durability were discussed.

• Korean journal of applied entomology
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• v.35 no.3
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• pp.254-259
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• 1996

The biochemical factors responsible for parathion resistance in a ethyl fenitrothion-selected Yumenoshima I11 (EF-30) strain of the housefly were examined. Great difference (167-fold) in the Iso was observed between the resistant EF-30 (R) and susceptible SRS (S) strains in vitro, suggesting that altered acetylcholinesterase (AChE) in the housefly strain was an important factor in the resistance. The in vitro degradative activity of parathion and paraoxon in both strains was associated with the microsomal and soluble fractions and required NADPH and reduced glutahione (GSH), respectively. The R strain possessed higher activity for GSH S-transferase than the S strain, and this enzyme appears to be important in the resistance mechanism. The R strain was highly resistant to parathion (101,487-fold), but substitution of the methoxy group for ethoxy group decreased the resistance level (25,914-fold) and parathion could be a substrate of GSH S-transferase. It is concluded that the combination of some factors (altered AChE, and enhanced activity of cytochrome P450 dependent monooxygenase and GSH S-transferase) could be sufficient to account for the extremely high level of resistance to parathion and parathion-methyl, although a possible involvement of other factor(s) can not be excluded.