• The Journal of Korean Medicine
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• v.29 no.4
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• pp.94-103
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• 2008

Objectives: The aim of this study was to determine whether celastrol, the triterpenoid component of Celastrus orbiculatus, offers neuroprotection against Parkinson's disease (PD) in mice administered 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine(MPTP). Methods: We examined how celastrol affected MPTP-induced neuronal loss of tyrosine hydroxylase (TH)-positive dopaminergic neurons in substantia nigra pars compacta (SNpc) in the midbrain of mice. C57BL/6J mice were divided into four groups: (1) saline-saline, (2) saline-celastrol, (3) MPTP-saline, and (4) MPTP-celastrol. The mice were injected intraperitoneally (i.p.) with four administrations of MPTP (18mg/kg) at 2 h intervals and then i.p. administered celastrol (3mg/kg) two times at 12 h after last celastrol administration. Expression of TH on the SNpc of brain tissues were analyzed at 7 days after the treatments by immunohistochemistry and Western blot. Results: Immunohistochemical analysis using TH antibody showed that celastrol provided significantly protective effects against MPTP-induced loss of TH-positive dopaminergic neurons in the SNpc region of the midbrain of mice. Our Western blot study also showed that celastrol significantly inhibits the MPTP-induced neuronal damage via the up-regulation of TH protein levels in MPTP mice. Conclusions: The present results suggest that it may be possible to use celastrol for the prevention of nigral degenerative disorders including PD, caused by exposure to toxic substances.

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

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.50-55
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• 2017

The objective of this study was to use the Lanchester equation to predict the outcome of our engagement between our unmanned aerial vehicle (UAV) (Blue Group) and enemy UAV (Red Group). Lanchester's law states that the power of corps is proportional to the number of combatants. A second law states that the power of corps is proportional to the square of the number of combatants. The first law is a suitable law for guerrilla warfare while the second law is known as the law suitable for all-out war. Therefore, the second law is commonly used. The second law of Lanchester's was used in this study to predict engagement results. We estimated the battle loss rate value to win the battle as well as the required power number. We also predicted power number to make the damage of our group less than one. The battle loss rate to reliably receive victory when the enemy's UAV and the ally's UAV are equal in number of combat units must be 1: 1.5 or more.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.303-303
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• 2017

Japanese agriculture has faced to several threats: aging and decrease of farmer population, global competition, and the risk of climate change as well as harsh and variable weather. On the other hands, the number of large scale farms is increasing, because farm lands have been being aggregated to fewer numbers of farms. Cost cutting, development of efficient ways to manage complicatedly scattered farm lands, maintaining yield and quality under variable weather conditions, are required to adapt to changing environments. Information and communications technology (ICT) would contribute to solve such problems and to create innovative technologies. Thus we have been developing an early warning and decision support system to reduce weather and climate risks for rice, wheat and soybean production in Japan. The concept and prototype of the system will be shown. The system consists of a weather data system (Agro-Meteorological Grid Square Data System, AMGSDS), decision support contents where information is automatically created by crop models and delivers information to users via internet. AMGSDS combines JMA's Automated Meteorological Data Acquisition System (AMeDAS) data, numerical weather forecast data and normal values, for all of Japan with about 1km Grid Square throughout years. Our climate-smart system provides information on the prediction of crop phenology, created with weather forecast data and crop phenology models, as an important function. The system also makes recommendations for crop management, such as nitrogen-topdressing, suitable harvest time, water control, pesticide spray. We are also developing methods to perform risk analysis on weather-related damage to crop production. For example, we have developed an algorism to determine the best transplanting date in rice under a given environment, using the results of multi-year simulation, in order to answer the question "when is the best transplanting date to minimize yield loss, to avoid low temperature damage and to avoid high temperature damage?".

• Journal of Nutrition and Health
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• v.48 no.5
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• pp.390-397
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• 2015

Purpose: In this study, we investigated the effects of chronic alcohol and excessive iron intake on mitochondrial DNA (mtDNA) damage and the progression of alcoholic liver injury in rats. Methods: Twenty-four Sprague-Dawley male rats were divided into four groups (Control, EtOH, Fe, and EtOH + Fe), and fed either control or ethanol (36% of total calories) liquid diet with or without 0.6% carbonyl iron for eight weeks. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, liver malondialdehyde concentrations were measured by colorimetric assays. Liver histopathology was examined by Hematoxylin-eosin staining of the fixed liver tissues. The integrity of the hepatic mtDNA and nuclear DNA was measured by long-range PCR. The gene expression levels of cytochrome c oxidase subunit 1 (Cox1) and NADH dehydrogenase subunit 4 (Nd4) were examined by real-time PCR. Results: Serum ALT and AST activities were significantly higher in the EtOH+Fe group, as compared to the Control group. Similarly, among four groups, liver histology showed the most severe lipid accumulation, inflammation, and necrosis in the EtOH + Fe group. PCR amplification of near-full-length (15.9 kb) mtDNA showed more than 50% loss of full-length product in the liver of the EtOH + Fe group, whereas amounts of PCR products of a nuclear DNA were unaffected. In addition, the changes in the mtDNA integrity showed correlation with reductions in the mRNA levels of mitochondrial gene Cox1 and Nd4. Conclusion: Our data suggested that the liver injury associated with excessive iron and alcohol intake involved mtDNA damage and corresponding mitochondrial dysfunction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.196-207
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• 2016

In monsoon climates, persistent shade is a troublesome weather condition with an impact on the growth and yield of corn (Zea mays L.). We imposed 7, 14, 21, and 28 days of consecutive shade (CS) on Gwangpyeongok and P3394 corn hybrids at the beginning of the kernel filling stages. Shade had little impact on leaf area and dry matter accumulation in the stem and leaves. However, dry matter accumulation in the ear was severely reduced by approximately 28% and 53% after 14 and 28 days of CS, respectively. For the components of grain yield, 7 and 14 days of shade did irreparable damage to the number of filled kernels, the kernel number per ear row, and the percent of filled kernels, but did little damage or reversible damage after removal of the shade to the 100-grain weight and the row number per ear. Shade significantly reduced the relative growth rate (RGR) due to a decrease in the net assimilation rate (NAR). These results suggest that source activity limitation by shade during the kernel filling stages leads to the inhibition of sink activity and size. The yield of biomass, ear, and grain logistically declined as the length of CS increased. Probit analysis revealed that the number of days of CS needed to cause 25% and 50% reductions in grain yield were 3.7 and 23.1, respectively. These results suggest that the plant yield loss induced by shade at the beginning of the kernel filling stages is mainly achieved within the first 7 days of consecutive shade.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.633-643
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• 2017

To examine the pro-apoptotic role of the human ortholog (YPEL5) of the Drosophila Yippee protein, the cell viability of Saccharomyces cerevisiae mutant strain with deleted MOH1, the yeast ortholog, was compared with that of the wild-type (WT)-MOH1 strain after exposure to different apoptogenic stimulants, including UV irradiation, methyl methanesulfonate (MMS), camptothecin (CPT), heat shock, and hyperosmotic shock. The $moh1{\Delta}$ mutant exhibited enhanced cell viability compared with the WT-MOH1 strain when treated with lethal UV irradiation, 1.8 mM MMS, $100{\mu}M$ CPT, heat shock at $50^{\circ}C$, or 1.2 M KCl. At the same time, the level of Moh1 protein was commonly up-regulated in the WT-MOH1 strain as was that of Ynk1 protein, which is known as a marker for DNA damage. Although the enhanced UV resistance of the $moh1{\Delta}$ mutant largely disappeared following transformation with the yeast MOH1 gene or one of the human YPEL1-YPEL5 genes, the transformant bearing pYES2-YPEL5 was more sensitive to lethal UV irradiation and its UV sensitivity was similar to that of the WT-MOH1 strain. Under these conditions, the UV irradiation-induced apoptotic events, such as FITC-Annexin V stainability, mitochondrial membrane potential (${\Delta}{\psi}m$) loss, and metacaspase activation, occurred to a much lesser extent in the $moh1{\Delta}$ mutant compared with the WT-MOH1 strain and the mutant strain bearing pYES2-MOH1 or pYES2-YPEL5. These results demonstrate the functional conservation between yeast Moh1 and human YPEL5, and their involvement in mitochondria-dependent apoptosis induced by DNA damage.

• Journal of Korean Society of Steel Construction
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• v.22 no.5
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• pp.421-433
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• 2010

The most typical deterioration of steel structures is corrosion damage. However, a method to evaluate residual load-carrying capacity of corroded steel structures is not yet established. It is difficult to check current serviceability and safety of the structures. In this study, compressive tests and finite element analyses were conducted on H-beams with corroded web. Then, the effect of corrosion damage on web crippling strength and evaluation methods of the web crippling strength are studied. Based on the tests, 4 H-beam specimens used in a subway construction site and 9 H-beam specimens with different web-thickness and damaged-height underwent compression-tests. To consider loading and supporting areas in the site, compressive loading was applied in the entire region of the upper and bottom flange in 5 H-beam specimens and applied partially on the regions of the upper and bottom flange in 8 specimens. The finite element analysis of 38 parametric model specimens simulating different corrosion damages was also carried out. From experimental and analytical results, the relationships between corrosion damages in the web and residual web crippling strength are presented. Factors web crippling strength was reduced are formulated by using residual average thickness and the standard deviation of the corroded web thickness. Also, a simple evaluation method of residual web crippling strength was proposed.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.851-856
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• 2012

There has been increasing the possibility of occurring the marine accident and become bigger the extent of damage with the growing number and high speed of ships. Also, there were tremendous loss of lives and properties in accidents of Hebei spirit in 2007 and Cheon Ahan war ship in 2010 with the insufficient salvage response and the lack of emergency response systems. When a ship has suffered an incident, the best way of preventing damage or pollution from its progressive deterioration would be to providing a place of refuge and to repair the damage rapidly. Therefore, it was examined the recent collision accident broken out near the Nam-Hae, and then suggested that it was necessary to be improved of the domestic salvage systems. It requires the procedures of providing a place of refuge, and the towing support system which make the damaged ship moved to the safe area, and joining of the ISU.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.103-103
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• 2018

Oenothera biennis, commonly known as evening primrose, a potential source of natural bioactive substances: flavonoids, steroids, tannins, fatty acids and terpenoids responsible for a diverse range of pharmacological functions. However, whether extract prepared from aerial part of O. biennis (APOB) protects skin against oxidative stress remains unknown. To investigate the protective effects of APOB against oxidative stress-induced cellular damage and elucidated the underlying mechanisms in the HaCaT human skin keratinocytes. Our results revealed that treatment with APOB prior to hydrogen peroxide ($H_2O_2$) exposure significantly increased viability, and the highest DPPH radical-scavenging activities and reducing power of HaCaT cells. APOB also effectively attenuated H2O2-induced comet tail formation and inhibited the $H_2O_2$-induced phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V-positive cells. In addition, APOB exhibited scavenging activity against intracellular reactive oxygen species (ROS) accumulation and restored the mitochondrial membrane potential loss by $H_2O_2$. Moreover, $H_2O_2$ enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase (PARP), a typical substrate protein of activated caspase-3, as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with APOB. Furthermore, APOB increased the levels of heme oxygenase-1 (HO-1), which is a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2). According to our data, APOB is able to protect HaCaT cells from $H_2O_2$-induced DNA damage and cell death through blocking cellular damage related to oxidative stress through a mechanism that would affect ROS elimination and activating the Nri2/HO-1 signaling pathway.