• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.217-223
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• 1993

To investigate the nature and location of the nisin-resistance determinant of Lactococcus lactis subsp. lactis 7962 (L. lactis 7962), a total plasmid DNA prepared from L. lactis 7962, a nisin producer, was used to transform L. lactis subsp. lactis LM0230, a plasmid-free and nisin-sensitive strain, by protoplast mediated transformation procedures. All of the nisin-resistant transformants acquired the ability to utilize sucrose at the same time, confirming the close linkage between these two determinants in L. lactis 7962. The plasmid DNA profiles of a few selected nisin-resistant transformants were examined by agarose gel electrophoresis. No common plasmid was found among the transformants and some small plasmids previously not present in L. lactis 7962 were detected. These transformants were named as L. lactis KL1, KL2, KL3, KL4, or KL5, respectively based on their plasmid profiles. Growth curves of all transformants were similar to that of L. lactis LM0230, but different from that of L. lactis 7962. L. lactis KL5 showed the highest level of resistance to nisin, growing up to 1, 200 IU nisin/ml after 40 hr incubation. Some nisin-sensitive derivatives of KL1 or KL2 were obtained by plasmid curing experiments. The plasmid DNA profiles of the nisin-sensitive KL1 derivatives were apparently the same as that of the KL1. All of the nisin-sensitive KL2 derivatives were plasmid-free, but a nisin-resistant strain with no apparent plasmid was also obtained. These results indicate that the nisin-resistance of the $Nis^r$ transformants is presumably mediated by the chromosomally located gene(s) rather than plasmid-encoded gene(s).

• Journal of Physiology & Pathology in Korean Medicine
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• v.35 no.4
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• pp.117-123
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• 2021

Gefitinib, a first generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), provides obvious clinical benefit in patients with EGFR-mutant non-small cell lung cancer (NSCLC). However, patients ultimately develop gefitinib resistance which mainly caused by EGFR T790M secondary mutation. In the current study, we investigated whether the root extract of Scutellaria baicalensis (SB) overcomes gefitinib resistance. Gefitinib-resistant H1975 human NSCLC cells (EGFR L858R/T790M double mutant) were treated with gefitinib and/or ethanol extract of SB (ESB) to evaluate the effect of ESB on the gefitinib sensitivity. The cell viability was measured by MTT assay and trypan blue exclusion assay. The colony-forming ability was evaluated by anchorage-dependent colony formation assay. Combined treatment with gefitinib and ESB markedly decreased the cell viability and colony formation than single treatment with gefitinib or ESB in H1975 cells. In addition, cells treated with both gefitinib and ESB exhibited a significant increase of sub-G1 DNA content which indicates apoptotic cells compared with those treated with gefitinib or ESB alone. As a molecular mechanism, combined treatment with gefitinib and ESB strongly downregulated the phosphorylation of ERK and JNK than single treatment with gefitinib or ESB. Taken together, our results demonstrate that ESB sensitizes H1975 cells to gefitinib treatment. We cautiously propose that ESB can be used in combination with gefitinib for the advanced NSCLC patients with acquired resistance to EGFR TKIs.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.114-123
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• 2015

Plants can respond and adapt to cold stress through regulation of gene expression in various biochemical and physiological processes. Cold stress triggers decreased rates of metabolism, modification of cell walls, and loss of membrane function. Hence, this study was conducted to construct coexpression networks for time-based expression pattern analysis of genes related to cold stress in Chinese cabbage (Brassica rapa ssp. pekinensis). B. rapa cold stress networks were constructed with 2,030 nodes, 20,235 edges, and 34 connected components. The analysis suggests that similar genes responding to cold stress may also regulate development of Chinese cabbage. Using this network model, it is surmised that cold tolerance is strongly related to activation of chitinase antifreeze proteins by WRKY transcription factors and salicylic acid signaling, and to regulation of stomatal movement and starch metabolic processes for systemic acquired resistance in Chinese cabbage. Moreover, within 48 h, cold stress triggered transition from vegetative to reproductive phase and meristematic phase transition. In this study, we demonstrated that this network model could be used to precisely predict the functions of cold resistance genes in Chinese cabbage.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.214-222
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• 2004

Purpose: Appropriate antibiotic therapy is important in childhood urinary tract infection and the selection of anibiotics is based on antimicrobial sensitivity of Escherichia coli. Extended-Spectrum ${\beta}-Lactamase(ESBL)$ is an enzyme produced by gram-negative bacilli that has the ability to hydrolyse penicillins, broad-spectrum cephalosporin and monobactam. There have been many reports of outbreaks of hospital infection by ESBL-producing organism. However, community-acquired infection with ESBL-producing organism are rare. This study was performed to retrospectively identify the incidence, characteristics and risk factors of ESBL (+) E. coli in community-acquired childhood UTI. Methods: In 288 children admitted in Ewha Womans University Hospital with E. coli UTI from Mar 2001 to February 2003, ESBL was isolated. ESBL was confirmed by the utilization of an automatized machine(Vitek GNS 433 card) using liquid medium dilution method according to National Committee for Clinical Laboratory Standard. The clinical characteristics, risk factors, antimicrobial resistance and treatment effectiveness were compared with ESBL(-) E. coli UTI. Results: Of 288 E. coli isolates, 31(10.8%) produced ESBL and 93.5%(29/31) occurred in infants younger than 6 month of age(P<0.01). No significant differences were noted in prior antibiotic use, prior admission history and underlying urogenital anomaly. Antimicrobial resistance was significantly higher in ESBL(+) E. coli compared with control patients (P<0.05). Although ceftriaxone showed 100% resistance in ESBL(+) E. coli, bacteriologic sterilization rate after ceftriaxone therapy was higher(96.8%). However, the recurrence rate of febrile UTI within 6 months was higher(25.8%) than control patients(6.6%). Conclusion: Epidemiologic study is required to find out any new risk factors of community-acquired ESBL(+) E. coli UTI and changes in selection of empirical antibiotics should be considered.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.721-728
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• 1994

The objective of this research is to analyze whether the ground granulated blast furnace (GGBF) slag, by-product of industry in domestic iron-foundary, can be useful as a mineral admixture for concrete by investigating physical and chemical property. In addition, according to making an fundamental experiment on mortar and concrete mixed with GGBF slag to some grade, examining the consistency, the compressive strength and the resistance to sulfate attack of concrete and mortar, the acquired results are that the compressive strength was increased and the resistance to sulfate attack was predominant.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.171-177
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• 2008

In this study, we investigated the induced defense response and protective effects against Stemphylium vesicarium by application of benzothiadiazole ($Bion^{(R)}$) and di-potassium phosphate salt $(K_2HPO_4)$ to onion. Onion leaves were sprayed with $Bion^{(R)}$ and $K_2HPO_4$, then inoculated 2 days later with a virulent strain of S. vesicarium under greenhouse conditions. Disease severity and activities of peroxidase (PO), polyphenoloxidase, phenylalanine ammonia-lyase (PAL) and phenol contents were evaluated in the treated leaf tissues. Reduction in the disease severity was observed in plants treated with $Bion^{(R)}$ and $K_2HPO_4$. Onion plants treated with $Bion^{(R)}$ and $K_2HPO_4$ and inoculated with the pathogen showed significantly higher PAL activity, PO activity, and phenol contents than inoculated water-treated plants 2 days after the treatment. In conclusion, the results of this study provide evidence that application of simple non-toxic chemical solutions as di-potassium phosphate and $Bion^{(R)}$ can control Stemphylium leaf blight of onion.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.165-173
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• 2013

Core loss has a major effect on heat generation in synchronous motors with surface-mounted permanent magnets (SPMs). It is essential to perform heat transfer analysis considering core loss in SPM because core loss is seriously affected by torque and speed of motors. In the present study, mechanical loss, core loss and coil loss are evaluated by measuring input and output energies under various driving conditions. For a better understanding heat transfer paths in synchronous motors, we developed a lumped thermal system analysis model. Subsequently, heat transfer analysis has been performed based on acquired energy loss, temperature data and thermal resistance with three types of SPM. It is shown that the torque constants decrease by Max. 10% as speed increase. At the rated torque, the core loss is Max. 10.9 times greater than the coil loss and the hysteresis loss of magnets is dominant in total loss.

• Journal of Chest Surgery
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• v.33 no.1
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• pp.1-6
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• 2000

Background: TNF-$\alpha$ plays a major role in producing left ventricular dysfunction cardio-myopathy pulmonary edema and inhibits the compensatory mechanism of congestive heart failure. IL-6 is an acute reactant of immune reaction and also known to control immune reaction but its function in the myocyte was not clearly investigated. Author's performed this experiment to investigate the contents of TNF-$\alpha$ and IL-6 on the assumption that TNF-$\alpha$ and IL-6 may reside in nonfailing heart that has gone cardiac surgery and play some role in cardiac function. Material and Method : Right auricular tissues were sampled from 12 patients who had undergone total corrective surgery for both congenital and acquired heart diseases from January 1998 to June 1998 in Kosin Universcfy Gospel hospital. The quantitive analysis of TNF-$\alpha$ and IL-6 were assessed by ELISA method in right auricular tissue. Hemodynamic values about the pressure of ventricle atrium aorta pulmonary artery and cardiac index pulmonary and systemic vascular resistance and cardiac output were measured by echocardiography and cardiac catheterization and biochemical analyses of LDH & AST were done before operation. statistical analysis was by Paired Student t-test. Patients were divided into children(under 15 years olds) and adults groups and the data was compared beween two groups. Conclusion: Mild pulmonary hypertension and increased pulmonary vascular resistance were existed in both group. The contents of tissue TNF-$\alpha$ IL-6 in each group were independent of each data.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.207-208
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• 2010

The building that supply tidal and splash zone was constructed near Seamangeum Gate Bridge. The specimens that will be tested for maintenance of gate bridge were exposed on the tidal and splash zone, totally about 650. The characteristics of strength, salt penetration profile, field application of surface repair material and section recover material will be acquired by periodical test. The program was developed to obtain optimal maintenance strategy of gate bridge as a marine concrete structure and to deposit experimental data, lab. test result, field test result, on its D/B. On this paper, the comparison of concrete and recover material in the salt penetration characteristics was expressed. The quantitative analysis of salt contents in concrete surface was most important so the improvement for the machine of gathering power of concrete and the apparatus of measuring chloride contents was proceeded at this time. The two conclusions were summarized like as - The resistance of chloride attack of concrete was appeared 2.5 times bigger than that of recover material - The resistance of chloride attack of polymer series was appeared more higher than that of others.

• Structural Engineering and Mechanics
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• v.57 no.3
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• pp.403-423
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• 2016

The challenges involved with fatigue damage assessment of steel catenary riser (SCR) in the touchdown zone (TDZ) are primarily due to the non-linear behaviour of the SCR-seabed interaction, considerable uncertainty in SCR-seabed interaction modelling and geotechnical parameters. The issue of fatigue damage induced by the cyclic movements of the SCR with the seabed has acquired prominence with the touch down point (TDP) interaction in the TDZ. Therefore, the SCR-seabed response is critical for reliable estimation of fatigue life in the TDZ. Various design approaches pertaining to the lateral pipe-soil resistance model are discussed. These techniques have been applied in the finite element model that can be used to analyse the lateral SCR-seabed interaction under hydrodynamic loading. This study investigates the sensitivity of fatigue performance to geotechnical parameters through a parametric study. In this study, global analyses are performed to assess the influence of vertical linear seabed springs, the lateral seabed model and the non-linear seabed model, including trench evolution into seabed, seabed normalised stiffness, re-penetration offset parameter and soil suction resistance ratio, on the fatigue life of SCRs in the TDZ.