• Journal of Aquaculture
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• v.12 no.3
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• pp.167-173
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• 1999

Blocking the 1st mitotic cleavage was performed in mud loach (Misgurmus mizolepis) using UV-irradiated cyprinid loach (M. anguillicaudatus) sperm and ternal shocks Optimum UV range for inactivation of cyprinid loach sperm and thermal shocks. Optimum UV range for inactivation of cyprinid loach sperm was between 3,150 to 4,050 ergs/m$m^2$. Heat shock treatment ($41^{\circ}C$ for 3mins) with various treatment initiation times ranged from 22 to 50 min post insemination resulted wide range of success for induced gynogenesis. Best result was obtained when haploid egges were shocked at 28 min after insemination (corresponding to metaphase division of the 1st cleavage); 26% of total eggs inseminated were viable diploid gynogens. The hatching success and early survival of the both meiotic and mitotic gynogenetic groups were significantly lower than those of control crosses (P<0.05). Maternal origin of induced gynogenetic mud loach was verified by multi-locus DNA fingerprinting.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.127-131
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• 2008

In the disk braking of the railway trains, kinetic energy of the vehicles is converted into thermal energy by friction between a brake disk and the pad materials. This can be cause of the iterative thermal shock and generates thermal cracks on the brake disk surface. In this study, we show the comparative thermal fatigue test procedures and thermal crack analysis process to evaluate the thermal fatigue characteristics of candidate materials designed for development of heat-resistant brake disk material. We carried out tests on the conventional brake disk materials used for Saemaul and Mugunghwa trains, then we comparatively analyzed the thermal crack initiation and propagation on the surface of a specimen. A thermal fatigue test procedure and a crack analysis process were suggested to evaluate the heat resistance of the developed materials at later studies.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.3
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• pp.143-148
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• 2015

In some pathogenic bacteria, there are RNA thermometers, which regulate the production of virulence associated factors or heat shock proteins depending on temperature changes. Like a riboswitches, RNA thermometers are located in the 5'-untranslated region and involved translational gene regulatory mechanism. RNA thermometers block the ribosome-binding site and start codon area under the $37^{\circ}C$ within their secondary structure. After bacterial infection, increased the temperature in the host causes conformations changes of RNA, and the ribosome-binding site is exposed for translational initiation. Because structural differences between open and closed forms of RNA thermometers are mainly mediated by base pairing changes, NMR spectroscopy is a very useful method to study these thermodynamically changing RNA structure. In this review, we briefly provide a fundamental function of RNA thermometers, and also suggest a proper NMR experiments for studying RNA thermometers.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.1 s.20
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• pp.5-13
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• 2005

In order to evaluate the credibility of the welded joint design for combat vehicle using A12519, the numerical analysis for the joint model has been studied and the results are compared with the experimental works by the impact projectiles. The numerical approach using LS-DYNA involves the process of the crack initiation and propagation as well as the applications of the failure criteria for both the ductile and brittle failures. The good agreement between the numerical and experimental works are proved.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1142-1147
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• 2006

A practical method for reducing the number of spot welds in automotive structures considering fatigue crack initiation life is suggested. At first, an influence index for the durability and the fatigue life of a spot weld itself is defined and then taken as the main effect of the DOE analysis. Spot welds that can be removed without serious reduction of durability through numerical experiments are selected by the results of DOE. The proposed method was applied to the shock tower and LCA(lower control arm) structure of a vehicle, which are important components in durability-related point of view.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.346-352
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• 2010

Introduction: Heat shock protein70 (HSP70) is a highly conserved family of proteins produced after a variety of stresses. Many studies reported that the overexpression of HSP70 can improve the prognosis of the patients with sepsis through a reduction of the nitric oxide concentration. However, these results only revealed the effect of HSP70 and nitric oxide. No studies have examined the relationship between HSP70 and nitric oxide. The aim of this study was to evaluate the effect of the overexpression of HSP70 on the expression of inducible nitric oxide synthase and the nitric oxide concentration. In addition, the mechanism of the relationship of HSP70 and inducible nitric oxide synthase (iNOS) in sepsis was examined. Materials and Methods: The experiments were performed on male sprague-dawley rats. Sepsis was induced by a cecal ligation and puncture (CLP). Glutamine (GLN) or saline was administered 1 hour after the initiation of sepsis. Serum and lung tissues were acquired from the rats 12 hours or 24 hours after the initiation of sepsis. The nitric oxide concentration, the expression of HSP70 in lung, and the gene expression of iNOS in lung were analyzed. The three groups, sham operation, CLP and CLP+GLN, were compared. Results: Compared to the other groups, in CLP+GLN, GLN administered after the initiation of sepsis enhanced the expression of HSP70 in the lung at 12 hours ($47.19{\pm}10.04$ vs. $33.22{\pm}8.28$, P=0.025) and 24 hours ($47.06{\pm}10.60$ vs. $31.90{\pm}4.83$, P=0.004). In CLP+GLN, GLN attenuated the expression of iNOS messenger RNA (mRNA) in the lung at 12 hours ($5,513.73{\pm}1,051.60$ vs. $4,167.17{\pm}951.59$, P=0.025) and 24 hours ($18,740.27{\pm}8,241.20$ vs. $9,437.65{\pm}2,521.07$, P=0.016), and reduced the concentration of nitric oxide in the serum at 12 hours ($0.86{\pm}0.48$ vs. $3.82{\pm}2.53$, P=0.016) and 24 hours ($0.39{\pm}0.25$ vs. $1.85{\pm}1.70$, P=0.025). Conclusion: The overexpression of HSP70 induced by the administration of GLN in sepsis attenuates the expression of the iNOS gene but reduces the nitric oxide concentration.

• Journal of the Korean Ceramic Society
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• v.42 no.8 s.279
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• pp.554-560
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• 2005

The engineering ceramic needs the properties of high strength, hardness, corrosion-resistance and heat-resistance in order to withstand thermal shock or applied nonuniform stresses without failure. The densely coated porous ceramics can be used for machine component, electromagnetic component, bio-system component and energy-system component by their high-performances from superior coating properties and light-weight characteristics due to the structure including pore by itself. In this study we controlled the porosity of silica and alumina, $8.2\~25.4\%$ and $23.4\~36.0\%$, respectively, by the control of sintering temperature and starting powder size. We made bilayer structures, consisting of a transparent glass coating layer bonded to a thick substrate of different porous ceramics by a thin layer of epoxy adhesive, facilitated observations of crack initiation and propagation. The elastic modulus mismatch could be controlled using different porous ceramics as the substrate layer. Then we applied 150 N force using WC sphere with a radius of 3.18 mm by Hertzian indentation. As a result, the crack initiation in the coating layer was delayed at lower porosity in the substrate layer, and the damage in the coating layer was relatively smaller at the bilayer structure coated on higher elastic substrate.

• Nuclear Engineering and Technology
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• v.24 no.1
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• pp.86-97
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• 1992

The purpose of this paper is to evaluate the direct vessel injection design from a pressurized thermal shock(PTS) viewpoint for the Combustion Engineering System 80+ A break of the main steam line from zero power and a 0.05 ft$^2$small break loss-of-coolant accident (LOCA) from full power were selected as the potential PTS events. In order to investigate the stratification effects in the reactor downcomer region, the fluid mixing analysis was performed using the COMMIX-IB code for steam line break and using the REMIX code for 0.05 ft$^2$small break LOCA. The stress distributions within the reactor vessel walls experiencing the pressure and the temperature transients were calculated using the OCA-P code for both events. The results of the analysis showed that a small break LOCA without decay heat presented the greatest challenge to the vessel, however, there is no crack initiation through end-of-life of the vessel with consideration of decay heat.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.1-11
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• 2014

Sympathetic detonation (SD) of high explosives occurs when a detonating donor initiates neighboring acceptors. The present study focuses on the hydrodynamic simulation of one-on-one sympathetic detonation of 155 mm charge filled with PBXN-109. Both unbuffered and buffered SD configurations are performed while changing the distance between each charge, in order to investigate the detonation sensitivity to a donor initiation. The cause of a SD is by a shock impact for the unbuffered case at a close range, while at a distant range, blast fragment penetration is the primary cause. The buffers can reduce the incident sensitivity to a SD by reducing the strengths of shock wave and impinging fragments.

• Journal of Aquaculture
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• v.6 no.1
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• pp.55-62
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• 1993

A tetraploid cyprinid loach, Misgurnus anguillicaudatus was induced by applying heat shock. The efficiency of inductions changed with the time of initiation of treatment and the duration of treatment. The highest incidence of tetraploid was obtained at the treatment of $41^{\circ}C$ for 3 min, 28 min after fertilization. Ploidy level was estimated by kariological examination and flow cytometric analysis. The tetraploid cyprinid loach had 4n = 100 chromosomes, while the diploid had 2n = 50. The erythrocytic volume of the tetraploid was 1.65 times larger than that of the diploid. The DNA content of the tetraploid and diploid showed 6.547 pg/cell and 3.067 pg/cell, respectively.