• Journal of Radiation Industry
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• v.7 no.1
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• pp.45-49
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• 2013

In tissue engineering application, a fibrous structure of scaffolds has been issued as an alternative system to regulate cell survival and tissue regeneration, and electrospinning technique has been popularly used to generate fibrous meshes or sheets mimicking the structure of native extracellular matrix (ECM). However, recent strategy in the scaffold development is expanded to provide the structural property as well as a biological property of native ECM, a variety of surface modification techniques have been used to introduce biological property. In this study, we developed biomimetic poly(L-lactide-co-${\varepsilon}$-caprolactone) (PLCL) nano- and micro-fibrous scaffolds as a unique platform with structural and biological properties with native ECM using electrospinning method and gamma-ray irradiation. Surface morphology of the scaffolds was observed by scanning electron microscopy, and alteration of surface property was evaluated with toluidine blue O staining, water contact angle measurement and ATR-FTIR analysis.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.280-285
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• 2011

As the plants grow in a fixed place, they can be a good indicator which reflects the level of environmental pollution. It is necessary for them to develop a strategy to cope with stress under unfavorable environmental conditions. In this study, spindle trees ($Euonymus$ $japonica$) were collected from a clean area (Kijang) as well as a heavily polluted area (Onsan) to check applicability of irradiation combined with plant bioassay to environmental monitoring. The leaves were irradiated with 0, 50 and 100 Gy of gamma rays, and then evaluated for antioxidative capacity with 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and superoxide dismutase (SOD) analysis. The result shows that there was no significant changes in SOD and EDA (Electron Donationg Ability) in the samples collected from a polluted area. In the meanwhile, SOD increased in the samples from a clean area until 6 to 10 hours after irradiation, then it decreased gradually until 24 hours after irradiation. In conclusion, the plants in the polluted area have developed higher resistance to oxidative stress induced by ionizing radiation than those in the relatively clean area. Irradiation combined with plant bioassay on enzymatic activities and free radical scavenging capacity has proven to be a possible tool for biomonitoring the environmental pollution.

• Journal of Radiation Protection and Research
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• v.48 no.1
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• pp.52-57
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• 2023

Background: Korea Atomic Energy Research Institute (KAERI) operates several nuclear research facilities licensed by Nuclear Safety and Security Commission (NSSC). The emergency preparedness requirements, GSR Part 7, by International Atomic Energy Agency (IAEA) request protection strategy based on the hazard assessment that is not applied in Korea. Materials and Methods: In developing the protection strategy, it is important to consider an accident scenario and its consequence. KAERI has tried the hazard assessment based on a hypothesis accident scenario for the major nuclear facilities. During the assessment, the safety analysis report of the related facilities was reviewed, the simulation using MELCOR, MACCS2 code was implemented based on a considered accident scenario of each facility, and the international guidance was considered. Results and Discussion: The results of the optimized protective actions were 300 m evacuation and 800 m sheltering for the High-Flux Advanced Neutron Application Reactor (HANARO), the evacuation to radius 50 m, the sheltering 400 m for post-irradiation examination facility (PIEF), 100 m evacuation or sheltering for HANARO fuel fabrication plant (HFFP) facility. Conclusion: The results of the optimized protective actions and its distances for the KAERI facilities for the maximum postulated accidents were considered in establishing the emergency plan and procedures and implementing an emergency exercise for the KAERI facilities.

• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.579-587
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• 2016

To obtain a stable energy supply and manage PhotoVoltaic (PV) systems efficiently, satellite imagery methods are being developed to estimate the solar PV potential. This study analyzed trends in the use of satellite imagery in solar PV and solar irradiation estimation technology. The imaging technology is used to produce solar energy resource maps. The trend analysis showed that the level of solar PV technology in Korea is 30% below that of advanced countries. It is impossible to raise such low-level technologies to the levels of advanced countries quickly. Intensive research and development is the only way to achieve the 80% technology level of advanced countries. The information produced in this process can contribute to the management of solar power plants. A valid technology development strategy would be to obtain effective data that can be used for fieldwork. Such data can be produced by estimating solar irradiation very accurately with several-hundred-meter resolution using Communication, Ocean, and Meteorological Satellites (COMS) and next-generation GEO-KOMPSAT 2A, developing core technologies for short- and medium-term irradiation prediction, and developing technologies for estimating the solar PV potential.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.180-185
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• 2000

Nano crystalline or non-crystalline particles have been widely used in various industrial area, such as ceramics, catalysis, electronics, metallurgy and optic device. In all applications, synthesizing the particles as small as possible and controlling the crystalline phase according to its purpose are necessary for the enhancement of processing performance. In some cases, non-agglomerated particles may be necessary for solving the packing problems. This motivates our attempt of controlling size, morphology, phase of nano titania and silica particles. If one can enhance sintering rate of small aggregates independently of collision rate, one may expect that original aggregates can be changed into volume equivalent spheres and thereby the decrease of collision frequency due to the change leads to much smaller rate of growth of the particles. This is the basic idea of our control strategy.

• Journal of Veterinary Clinics
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• v.21 no.3
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• pp.253-258
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• 2004

DNA double-strand break (DSB) is a serious treat for the cells including mutations, chromosome rearrangements, and even cell death if not repaired or misrepaired. Ku heterodimer regulatory DNA binding subunits (Ku70/Ku80) bound to double strand DNA breaks are able to interact with 470-kDa DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and the interaction is essential for DNA-dependent protein kinase (DNA-PK) activity. The Ku80 mutants were designed to bind Ku70 but not DNA end binding activity and the peptides were treated in breast cancer cells for co-therapy strategy to see whether the targeted inhibition of DNA-dependent protein kinase (DNA-PK) activity sensitized breast cancer cells to ionizing irradiation or chemotherapy drug to develop a treatment of breast tumors by targeting proteins involved in damage-signaling pathway and/or DNA repair. We designed domains of Ku80 mutants, 26 residues of amino acids (HN-26) as a control peptide or 38 (HNI-38) residues of amino acids which contain domains of the membrane-translocation hydrophobic signal sequence and the nuclear localization sequence, but HNI-38 has additional twelve residues of peptide inhibitor region. We observed that the synthesized peptide (HNI-38) prevented DNA-PKcs from binding to Ku70/Ku80, resulting in inactivation of DNA-PK complex activity in breast cancer cells (MDA-465 and MDA-468). Consequently, the peptide treated cells exhibited poor to no DNA repair, and became highly sensitive to irradiation or chemotherapy drugs. The growth of breast cancer cells was also inhibited. These results demonstrate the possibility of synthetic peptide to apply breast cancer therapy to induce apoptosis of cancer cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1414-1418
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• 2017

Inhibition of advanced glycation end product (AGE) formation is a valuable therapeutic strategy for the regulation of diabetic complications. This study was conducted to identify potential therapeutic targets of anti-diabetic complications from irradiated mangiferin using AGE formation assay. Radiolytic degradation of the xanthone glucoside mangiferin by gamma-irradiation resulted in three degraded mangiferin analogues: mangiferdiol (1), mangiferinol (2), and isomangiferinol (3). Structures of the three newly generated compounds were characterized by interpretation of nuclear magnetic resonance ($^1H$, $^{13}C$ NMR, $^1H-^1H$ COSY, HSQC, HMBC, and NOESY) and mass spectroscopic data. The anti-diabetic complication of the generated mangiferin derivatives were tested using in vitro AGE formation method. Among the tested degraded products, mangiferinol (2) and isomangiferinol (3) exhibited significantly improved potency against AGE formation inhibitory activities with $IC_{50}$ values of $5.6{\pm}0.8$ and $7.6{\pm}0.9{\mu}M$, respectively. This result implies that xanthone derivatives generated from gamma-irradiated mangiferin might be beneficial for prevention of diabetic complication and related diseases.

• Journal of Ginseng Research
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• v.35 no.3
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• pp.261-271
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• 2011

Chemical radiation protection is an important strategy to protect living beings against the deleterious effects of radiation. In the present study, the radioprotective effect of hydro-alcoholic extract of Panax ginseng extract (PGR-HAE) was studied on radiation-induced deleterious alterations in Swiss albino mice. Oral administration of such extract (25 mg/kg b wt/day/animal) for 5 consecutive days, half an h. before whole-body exposure to 6 Gy gamma radiation, enhanced the 30 days survival and also inhibited the radiogenic sickness, weight loss and life shortening. PGR-HAE ameliorated radiation induced depletion in blood constituents at different necropsy intervals between 12 h to 30 d, and significantly increased the number of femoral spleen colony forming units that survived after irradiation. Furthermore, it checked depletion of glutathione and antioxidant enzymes (superoxide dismutase, catalase, and glutathione S-transferase) as well as elevation of lipid peroxidation (LPO) level in blood and liver. The significant reduction in the yield of LPO demonstrates that PGR-HAE protects the membranes against radiation-induced oxidative damage. These findings conclude that such plant extract provides significant radioprotection, and it may be potentially valuable in the prevention of injuries caused during planned and unplanned radiation exposure.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.9 no.1
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• pp.20-24
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• 2013

Reactor Vessel Internals(RVIs), which are installed within the reactor pressure vessel and support the fuel assembly, take responsibility for safety of reactor core. In operating Nuclear Power Plants(NPPs), the RVIs have been exposed to severe conditions such as neutron irradiation, high temperature, high pressure, and high velocity of coolant flow and have degraded by materials aging with long-term operation. Therefore, the effective aging management plan and the appropriate regulatory requirements are necessary to maintain the integrity of RVIs. The purpose of this paper is to provide a review guide for Periodic Safety Review(PSR) of RVIs in presurized water reactor. The review guide is developed based on the revised review guides and reports established from IAEA and USNRC, and the analysis results of design characteristics, aging mechanisms, and operating experiences of RVIs in domestic and international NPPs. Consequently, the developed review guide for PSR of RVIs is expected to contribute an overall strategy and standard for the PSR of RVIs.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.775-783
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• 2016

The identification of novel reagents that exert a biological ultraviolet (UV)-protective effect in skin cells represents an important strategy for preventing UV-induced skin aging. To this end, we investigated the potential protective effects of Ettlia sp. YC001 extracts against UV-induced cellular damage in normal human dermal fibroblasts (NHDFs). We generated four different extracts from Ettlia sp. YC001, and found that they exhibit low cytotoxicity in NHDFs. The ethyl acetate extract of Ettlia sp. YC001 markedly decreased UVB-induced cytotoxicity. Additionally, the ethyl acetate extract significantly inhibited the production of hydrogen peroxide-induced reactive oxygen species. Moreover, it inhibited UVB-induced thymine dimers, as confirmed by luciferase assay and thymine dimer dot-blot assay. Thus, the study findings suggest Ettlia sp. YC001 extract as a novel photoprotective reagent on UVB-induced cell dysfunctions in NHDFs.