• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.30 no.6
• /
• pp.235-241
• /
• 2018

In this study, we collected cases of accidents caused by swell in the east coast of Korea from 2013 to 2017. The location of the accident, the season, the type of coast and the type of damage were classified and the correlation between the accident and the wave data was analyzed by collecting the observation data of the nearby area at the time of the accident. Also, based on the results of the coastal disaster vulnerability assessment of Korea Hydrographic and Oceanographic Agency, the vulnerability grades of swell accidents area were evaluated. In swell accident area, the average grade of the wave exposure index was 4.91, the wave sensitivity index was 3.87, and the wave impact index was 4.90. As a result, most of the swell accidents occurred in the 5 grade (very vulnerable level) of the wave impact index, and the area of the east coast (78.7%) of the same 5 grade was classified into five types according to the wave sensitivity index result. Finally, a countermeasures was taken for characteristics of each type.

• Journal of Embryo Transfer
• /
• v.32 no.4
• /
• pp.257-265
• /
• 2017

Ferulic Acid (FA) is a metabolite of phenylalanine and tyrosine, a phenolic compound commonly found in fruits and vegetables. Several studies have shown that FA has various functions such as antioxidant effect, prevention of cell damage from irradiation, protection from cell damage caused by oxygen deficiency, anti-inflammatory action, anti-aging action, liver protective effect and anti-cancer action. In this study, we investigated the maturation rate, intracellular glutathione (GSH) and reactive oxygen species (ROS) of porcine oocytes by adding FA to the in vitro maturation (IVM) medium and examined subsequent embryonic developmental competence at 5% oxygen through parthenogenesis. There is no significant difference between the control group ($0{\mu}M$) and treatment groups ($5{\mu}M$, $10{\mu}M$, $20{\mu}M$) on maturation rates. Intracellular GSH levels in oocyte treated with $5{\mu}M$ of FA significantly increased (P < 0.05), and $20{\mu}M$ of FA revealed significant decrease (P < 0.05) in intracellular ROS levels compared with the control group. Oocytes treated with FA exhibited significantly higher cleavage rates (79.01% vs 89.19%, 92.20%, 90.89%, respectively) than the control group. Oocytes treated with $10{\mu}M$ showed significantly higher blastocyst formation rates (28.3% vs 40.3%, respectively) after PA than the control group. Total cell numbers in blastocyst of $10{\mu}M$ FA displayed significantly higher (39.4 vs 51.9, respectively) than the control group. In conclusion, these results suggested that treatment with FA during IVM improved the developmental potential of porcine embryos by increasing intracellular GSH synthesis and reducing ROS levels. Also, there was an improvement of cleavage rate, blastocyst formation and total cell numbers in blastocysts. It might be associated with Keap1-Nrf2 pathway as an antioxidant regulate pathway that plays a crucial role in determining the sensitivity of cells to oxidative damages by regulating the basal and inducible expression of enzymes which is related to detoxification and anti-oxidative effects, stress response enzymes and/or proteins and ABC transporters.

• Food Science and Preservation
• /
• v.8 no.2
• /
• pp.206-212
• /
• 2001

Water extract of green tea(GTW) and 70% ethanol extract of green tea(GTE) were prepared for the test of antibacterial activity. The sensitivity of Staphylococcus aureus and Salmonella typhimurium to the green tea extracts in various pH of culture broth was tested. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts was adjusted to pH 5.0∼7.0 and inoculated with 10$\^$5/∼10$\^$6/ cells/ml of each bacteria. The plate counting method and clear zone test were used to determine inhibitory effect of green tea extracts. Green tea extracts completely inhibited the growth of S. aureus at 0.5% level and bactercidal at 0.5∼1.0% level of GTW and GTE at pH 5.0∼7.0. Green tea extracts were bactercidal to S. typhimurium at 1.5∼2.0% level of GTW and 1.0∼2.0% level of GTE at pH 7.0. Sal. typhimurium was more resistant than S. aureus. in same concentration of green tea extracts at same pH. The resistance of S. aureus and Sal. typhimurium was increased with decreasing pH of culture broth. The morphology of S. aureus cells treated with green tea extracts showed damage of cell wall and cytoplasmic membrane. Severely damaged cells of S. aureus lost electron dense material and cytoplasm. Green tea extracts stimulated autolysis and cell death of S. aureus. This result suggests that green tea extracts can be used as an effective natural antibacterial agent in food.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.16
• /
• pp.6955-6960
• /
• 2014

Background: The cytokinesis-block micronucleus (CBMN) assay is a standard cytogenetic tool employed to evaluate chromosomal damage subsequent to pesticide exposure. Objectives: To evaluate the pooled levels of total micronuclei (MN) and binucleated cells with micronuclei (MNC) in 1000 binucleated lymphocytes among population occupationally exposed to pesticides and further determine the more sensitive biomarker of CBMN. Materials and Methods: A meta-analysis on the pooled levels of MN and MNC in binucleated lymphocytes among occupationally pesticide-exposed populations was conducted using STATA 10.0 software and Review Manager 5.0.24 in this study. Results: We found significant differences in frequencies of MN and MNC in 1000 binucleated lymphocytes between pesticide-exposed groups and controls, and the summary estimates of weighted mean difference were 6.82 [95% confidence interval (95% CI): 4.86-8.78] and 5.08 (95% CI: 2.93-7.23), respectively. However, when we conducted sensitivity analyses further, only the MN remained statistically different, but not the MNC, the summary estimates of weight mean difference were 2.86 (95% CI: 2.51-3.21) and 0.50 (95% CI: -0.16-1.17), respectively. We also observed pesticide-exposed subjects had significantly higher MN frequencies than controls among smokers and nonsmokers, male and female populations, and American, Asian and European countries in stratified analyses. Conclusions: The frequency of MN in peripheral blood lymphocytes might be a more sensitive indicator of early genetic effects than MNC using the CBMN assay for occupationally pesticide-exposed populations.

• The Plant Pathology Journal
• /
• v.35 no.6
• /
• pp.654-661
• /
• 2019

The soybean cyst nematode, Heterodera glycines, is a major plant-parasitic nematode that has caused important economic losses to Korea's soybean production. Four species of cyst nematodes, H. schachtii, H. glycines, H. trifolii, and H. sojae, all belong to schachtii group are coexist in field soil in Korea. The rapid identification of the nematode is crucial for preventing crop damage and in decision making for controlling this nematode. This study aimed to develop a species-specific primer set for quantitative PCR (qPCR) assay of H. glycines. The specific primer set (HGF1 and HGR1) for H. glycines was designed based on the cytochrome c oxidase subunit I (COI) sequence of mitochondrial DNA. After optimization, it is possible to identify the H. glycines using a qPCR assay with DNA extracted from a single cyst and single second-stage juvenile (J2). The specificity was confirmed by the absence of SYBR fluorescent signals of three other Heterodera species. A serial dilution of DNA extracted from a single cyst was obtained for the sensitivity test. The result showed that the standard curve of the test had a highly significant linearity between DNA concentration and Ct value (R² = 0.996, slope = -3.49) and that the detection limit concentration of DNA of the primer set was 10 pg of DNA per reaction. Our findings suggested that H. glycines could be distinguished from H. sojae and other Heterodera species when a qPCR assay is used with a specific primer set.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2003.11a
• /
• pp.244-251
• /
• 2003

A two-dimensional BEM code, $FRACOD^{2D}$, was applied to simulate fracture initiation and propagation processes in a rock pillar during an in situ heater test of a rock pillar planned at the $\"{A}sp\"{o}$ Underground Rock laboratory of SKB, in Southern Sweden. To take the advantage of conventional BEM for simulating fracturing processes, but without efforts for domain integral transformation, a hybrid approach is developed to simulate the fracturing processes in rock pillar under coupled thermo-mechanical loading. The code FRACOD was used for simulating the fracture initiation and propagation processes with its boundary tractions reflecting the effects of the initial and redistributed thermomechanical stresses in the domain of interest at multiple excavation and heating steps were produced by a special algorithm of stress inversion, based on resultant thermo-mechanical stress fields at each excavation and heat loading step by a FEM code without considering fracturing processes. This hybrid approach can take the advantages of both types of numerical methods and avoids their shortcomings for fracturing process simulation and domain effects, respectively. In this paper, we present the hybrid approach for the stress, displacements, and fracturing processes at sequential excavation and heating steps of the in situ heater test as a predictive modelling, the formulation of the fracturing models and the predictive results. Two sections of borehole depth, 0.5 m and 1.5 m below the tunnel floor are considered. The pillar area is modelled with the FRACOD and the stress field produced by excavation and heating is transferred with corresponding boundary stresses. From the modelling results, the degree of fracturing and damage are evaluated for 120 days of heating. Dominated shear fracturing in the vicinity of the central pillar was observed from the models at both sections, but spalled area appears to be limited. Based on the modelling results, a sensitivity study for the effect of pre-existing fractures in the vicinity of the holes is also conducted, and the initiation and evolution of EDZ around the deposition holes are investigated using this particular numerical technique.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.5B
• /
• pp.313-320
• /
• 2012

A hybrid floating structure system combined with pontoon and semi-submersible type modules is proposed. This new system can reduce tensile forces of bottom slabs which could cause fatal damage of concrete floating structures. We performed a parametric study on the dimensions of this new system and investigate the sensitivity of the parameters to the behavior. In order to investigate various cases efficiently, we developed a simple two-step static analysis method for the fluid-structure interaction. An optimum system is derived from the investigation of the analysis results, weights and drafts of the hybrid structure. This study shows that introducing this new system to concrete floating structures is an effective way to reduce the tensile force of the bottm slab of such a floating structure. Also, it was found that when the length of the semi-submersible module is about 15%, the behavior would be optimal in the considered case.

• Kidney Research and Clinical Practice
• /
• v.37 no.4
• /
• pp.338-346
• /
• 2018

Background: The most common cause of acute kidney injury (AKI) in pregnancy is preeclampsia. Serum cystatin C (CysC) is a potential biomarker of early kidney damage as its levels are not disturbed by volume status changes in pregnancy, and serum CysC levels could serve as a replacement for conventionally used creatinine. In this study, we investigated the serum levels of CysC in severe preeclampsia cases and the associations between CysC levels and poor obstetric outcomes. Methods: Our cohort included severe preeclampsia patients with a normal serum creatinine level. Creatinine was measured to calculate estimated glomerular filtration rate (eGFR) based on the Cockcroft and Gault, Modification of Diet in Renal Disease Study (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, while CysC was measured to calculated eGFR based on a CysC-based equation. We then evaluated the correlations between serum CysC level, eGFR, and obstetric outcomes. Results: Twenty-six patients were evaluated of which 38.5% delivered preterm and 30.8% had low-birth weight babies. Unlike creatinine-based eGFR and CysC-based eGFR, serum CysC demonstrate significant negative correlation with gestational age. Receiver operating characteristic curve analysis indicated that serum CysC is a potential biomarker of preterm delivery with a cut-off serum level of 1.48 mg/L with 80% sensitivity and 75% specificity. Conclusion: GFR estimation using CysC is likely to be inaccurate in pregnancy. However, we found a significant correlation between preterm delivery and serum CysC level. Our results suggest that serum CysC level has the potential to predict preterm delivery in severe preeclampsia patients.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.12
• /
• pp.1535-1541
• /
• 2019

To carry out safe and rapid decontamination in radiological accident areas, acquisition of various information on radiation sources is needed. In particular, to figure out the location and distribution of radiation sources is essential for rapid follow-up and removal of contaminants as well as minimizing worker damage. The radiation distribution detection device is used to obtain the position and distribution information of the radiation source. In the case of a radiation distribution detection device, a detection sensor unit is generally composed of a single sensor, and the detection range is limited due to the physical characteristics of the single sensor. We applied a calibration detector for controlling the detection sensitivity of a single sensor for radiation detection and improved the limited detection range of radiation dose rate. Also, gamma irradiation test confirmed the improvement of radiation distribution detection range.

• Current Optics and Photonics
• /
• v.6 no.2
• /
• pp.143-150
• /
• 2022

Anti-resonant hollow-core photonic crystal fiber (AR-HCF) has unique advantages, such as low nonlinearity and high damage threshold, which make it a promising candidate for high-power laser delivery at distances of tens of meters. However, due to the special structure, optical properties such as mode-field profile and bending loss of hollow-core fibers are different from those of solid-core fibers. These differences have limited the widespread use of AR-HCF in practice. In this paper we conduct numerical analysis of AR-HCFs with different structural parameters, to analyze their influences on an AR-HCF's optical properties. The simulation results show that with a 23-㎛ air-core diameter, the fundamental mode profile of an AR-HCF can well match that of the widely used Nufern's 20/400 fiber, for nearly-single-mode power delivery applications. Moreover, with the ratio of cladding capillary diameter to air-core diameter ranging from 0.6 to 0.7, the AR-HCF shows excellent optical characteristics, including low bending sensitivity while maintaining single-mode transmission at the same time. We believe these results lay the foundation for the application of AR-HCFs in the power delivery of high power fiber laser systems.