• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.3
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• pp.75-86
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• 1986

The welded joint of the rail of railroad had shown the complicated behaviour of fatigue crack growth due to the effect of low toughness, residual stress, welding stress and strain etc. resulting from welding. Also, the welding connection has been necessary as making longer the rail, thus fatique fracture has often occurred at welded joints. From above, in this paper, faigue test was done at base metal, gas pressure and thermit welded joints to give the basic data to construct S-N diagrams. From this, it was known that the base metal was better than welded joint and gas pressure better than thermit welded joints in the resistance against the behaviour of fatigue crack growth. And it was also found that it is very dangerous to control fracture only by the method of material mechanics.

• Molecules and Cells
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• v.37 no.2
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• pp.100-108
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• 2014

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu,Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.5
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• pp.780-790
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• 1997

In this study, the stress-strain relations of steels have been calculated as a function of microstructural morphologies of each phase by use of FEM program(i.e. ABAQUS). The mechanical behavior of low carbon steels is affected by the microstructural factors such as yield ratio, volume fraction, shape and distribution of each phase and so on. The effects of shape, volume fraction and yield ratio of each phase on the mechanical behavior were analyzed by using unit cell and whole specimen size models. Results obtained are summarized as follows. As the yield ratio of hard phase to that of soft phase and volume fraction of hard phase were increased, stress level of flow curves were increased. It was found that in whole specimen size model, as the particle size was decreased, higher stress level was shown. Lastly the relationship between microstructure and tensile properties was examined by using the steels with various microstructural morphologies.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.7 no.2
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• pp.75-81
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• 2012

Objectives : According to previous reports, heating-conduction acupuncture treatment is very effective for sprain and strain of ligament. But there was no report about pain aggravation by heating-conduction acupuncture and relief from bee venom injection. In this article, we report two cases of pain aggravation by heating-conduction acupuncture treatment and relief from bee venom injection. Methods : We used heating-conduction acupuncture treatment on possible sprain of sacroiliac ligament diagnosed by physical examination. Outcomes were measured by Visual Analogue Scale(VAS), Range of Motion(ROM) and Belt test, Goldthwait test. Results : The patient has shown an aggravation on pain and ROM. And after we use subcutaneous bee venom injection, pain has relieved and ROM improved. Belt test, Goldthwait test also changed from positive to negative. Conclusions : In this report, we assured the effect of Bee venom injection. Further well-designed, controlled studies and more cases are needed to differentiate the indication of heating-conduction acupuncture and bee venom injection.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.1
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• pp.1-14
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• 2020

The latest definition of a prebiotic is "a substrate that is selectively utilized by host microorganisms conferring a health benefit"; it now includes non-food elements and is applicable to extra-intestinal tissues. Prebiotics are recognized as a promising tool in the promotion of general health and in the prevention and treatment of numerous juvenile diseases. Prebiotics are considered an immunoactive agent, with the potential for long-lasting effects extending past active administration of the prebiotic. Because of its extremely low risk of serious adverse effects, ease of administration, and strong potential for influencing the composition and function of the microbiota in the gut and beyond, the beneficial clinical applications of prebiotics are expanding. Prebiotics are the third largest component of human breast milk. Preparations including galactooligosaccharides (GOS), fructooligosaccharides (FOS), 2'-fucosyllactose, lacto-N-neo-tetraose are examples of commonly used and studied products for supplementation in baby formula. In particular, the GOS/FOS combination is the most studied. Maintaining a healthy microbiome is essential to promote homeostasis of the gut and other organs. With more than 1,000 different microbial species in the gut, it is likely more feasible to modify the gut microbiota through the use of certain prebiotic mixtures rather than supplementing with a particular probiotic strain. In this review, we discuss the latest clinical evidence regarding prebiotics and its role in gut immunity, allergy, infections, inflammation, and functional gastrointestinal disorders.

• Korean Journal of Poultry Science
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• v.23 no.3
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• pp.121-128
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• 1996

A feeding trial was conducted to evaluate the effect of supplementing MAXIMINERAL(72)(MM), a cornmercial product of Ca, Mg-bentonite, to the broiler diet. One thousand hatched rnale broiler chickens(Cobb strain) were randomly assigned to 4 dietary treatments; MM 0% (control), MM 1%, MM 2%, and MM 2% + tricalciurnphosphate (CaP) 0.5%. Each treatment had 5 replicates of 50 birds each. Birds were grown on floor and fed ad libitum for 5 wk. Through the whole period, weight gain and feed intake were not significantly different among treatments. However, weight gain of MM 2% + CaP 0.5% group was highest and orthogonal contrast showed that the feed intake during the period of 0~2 wk was significantly(p<0.01) lower in MM supplemented groups than the control. Feed efficiency (feed /gain) of MM supplemented groups were significantly better than the control. Feed efficiency of the control was significantly(p<0.05) higher than MM 1% and MM 2% + CaP 0.5% groups but not different from MM 2% group. Contents of ash, Ca and P of tibia were not significantly different among treatments but that of P tended to be low in MM 1% and MM 2% groups. There were significant (p<0.01) differences in plasma alkaline phosphatase (AP) activity among treatments. The highest AP activity was shown in MM 2% + CaP 0.5% group followed by the control, MM 2% and MM 1% group. It was concluded that supplernentation of MM at the level of 1% of broiler diet significantly improves feed efficiency and adjustment of P level rnay further improve the performance of the broiler chickens.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.9-12
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• 1995

The molar ratio of sterol to phospholipid differed from yeast strains, and the ratio was relatively higher in non-freeze-tolerant yeast strain, S. cerevisiae than freeze-tolerant yeast strains, D$\sub$2-4/ or CFY. Phospholipid composition of these yeast were also investigated. Phosphatidylcholine content was larger among phospholipids in all yeasts. Higher ratio of PC/PE was found in freeze-tolerant yeast than non-freeze-tolerant yeast. Higher proportion of linolein acid(18 : 2) against total fatty acid attached to phospholipid was observed in D$\sub$2-4/ than S. cerevisiae or CFY, and the degree of unsaturation of fatty acid was higher in D$\sub$2-4/ and CFY than in S. cerevisiae. These results suggested that the fluidity of yeast cell membrane was different in yeast strains, which might result in the difference in freeze-injury of yeast at low temperatures.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.27-38
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• 2007

A series of forced vibration tests and ambient vibration measurement was conducted on a four-story reinforced concrete building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively, and ambient vibrations were measured before and after each forced vibration test. Accelerations, interstory displacements, and curvature distributions were monitored using accelerometers, LVDTs and concrete strain gauges. Natural frequencies and the associated mode shapes fur the first 7 modes were identified. Fundamental frequencies determined from the eccentric mass shaker tests were 70% to 75% of the values determined using ambient vibration data, and 92% to 93% of the values determined using the linear shaker test data. Larger frequency drops were observed in the NS direction of the building, apparently due to damage that was induced during the Northridge earthquake.

• Korean journal of applied entomology
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• v.34 no.1
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• pp.40-45
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• 1995

Eight field-collected populations of the two-spotted spider mites, Tetranychus urticae (Koch) from apple orchards of different geographical areas were tested for resistance to seven acaricides by leaf disk method in comparison with a susceptible strain. Marked regional variations of susceptibility were observed. Only low to moderate resistance to azocyclotin, fenpropathrin, propargite, and abamectin was obtained. However, high resistance to dicofol, fenpyroxymate, and pyridaen by eight field-collected populations was produced. Resistance to dicofol and fenpyroxymate was widespread. All of the strains tested were susceptible to one or more o the acaricides used. These results indicate that careful selection of the chemical used against any population of the two-spotted spider mite might result in satisfactory control.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.147-153
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• 2013

Recently the primary water stress corrosion cracking(PWSCC) has occurred in the dissimilar metal weld region between pressurizer nozzle and safe-end in nuclear power plants(NPPs). As material of the pressurizer nozzle, SA508 Gr. 3 low alloy steel was used. F316L stainless steel and Alloy 82/182 were used as safe-end and weld metal, respectively. Although mechanical properties are needed for evaluation of the structural integrity against flaw in the material, material specification and standard don't supply those properties. Therefore, the present study conducted tensile and fracture toughness tests on SA508 Gr.3 and F316L stainless steel at ambient temperature and operating temperature of NPPs and reported the tested results.