• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.674-674
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• 2004

• Nutrition Research and Practice
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• v.5 no.5
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• pp.389-395
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• 2011

In the present study, a suitable drying method was developed for citrus press cakes (CPCs), which are produced as a by-product in citrus juice plants, and the protective effect of methanol extract of CPCs prepared by far-infrared radiation (FIR) drying against $H_2O_2$-induced DNA damage was evaluated versus that of freeze-dried CPCs. Methanol extract of FIR-dried CPCs exhibited comparatively good ROS scavenging activity versus the freeze-dried CPCs at the concentration of 100 ${\mu}g$/mL. The extract strongly enhanced the cell viability against $H_2O_2$-induced oxidative damage in Vero cells. Lipid peroxidation inhibitory activity of the extract from FIR-dried CPCs was comparable to that of the extract from freeze-dried CPCs. This sample also exhibited good protective effects against $H_2O_2$-mediated cell apoptosis as demonstrated by decreased apoptotic body formation in the nuclear staining with Hoechst 33342. In the comet assay, the CPC extracts exhibited strong inhibitory effects against $H_2O_2$-mediated DNA damage in a dose-dependent manner. Thus, this study demonstrated that FIR drying effectively preserves CPC as a functionally important natural antioxidant source and the FIR drying can be adapted for drying CPCs and is more economical for massive production than freeze drying.

• Journal of Sensor Science and Technology
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• v.9 no.5
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• pp.350-356
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• 2000

The optimum composition ratios of primary solute(p-terphenyl) and secondary solute(popop) have been investigated in order to fabricate plastic scintillator with higher light output and less radiation damage. The radiation damage induced by $^{60}Co$ $\gamma$-irradiation depends on mainly the concentration of secondary solute. The spectral range of the luminescence was $400{\sim}450\;nm$, its peak emission appeared at 415 nm. The transmittance and the light output were not changed by radiation damage up to $1{\times}10^4\;Gy$ irradiation with $^{60}Co$ $\gamma$-rays.

• The Korea Journal of Herbology
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• v.32 no.5
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• pp.13-18
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• 2017

Objectives : The aim of this study is to investigate anti-inflammation of Leonurus sibiricus methanol extract against UVB-damage in fibroblast. The skin is continuously exposed to damage from environmental stresses. UV radiation causes a variety of biological effects especially on the skin, including inflammation and photoaging. Methods : In this study, we tried to search for Leonurus sibiricus which exhibit protective activities against UVB-induced cytotoxicity and oxidative cell death, NO and $PGE_2$ production. HS68 cells were exposed to UVB ($120mJ/cm^2$) and treated with various concentrations (0, 0.25, 0.5, 1, 2, 4, $8mg/m{\ell}$) of Leonurus sibiricus methanol extract for additional 24 h. Intracellular reactive oxygen species (ROS) levels generated by UV radiation were detected using a spectrofluorometer after DCF-DA staining. Also, HS68 cells were irradiated with UVB and then treated with Leonurus sibiricus methanol extract for 12 h. The lipid peroxidation was assayed by measuring the levels of 8-isoprostane secreted into the culture medium. Results : UVB-induced cytotoxicity and cell death were effectively suppressed by treatment of Leonurus sibiricus aqueous methanol extracts. Oxidative cell damage was mediated $PGE_2$ in UVB-induced HS68 fibroblast cell, which was significantly inhibited by treatment with Leonurus sibiricus extracts. Also, the protective effect of these extract seemed to be mediated by inhibited intracellular ROS generation and lipid peroxidation in dose-dependent manner. Conclusion : These results suggest that Leonurus sibiricus aqueous methanol extracts may have anti-aging effects new functional materials against oxidative UVB stress-mediated skin damages.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.282-287
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• 2011

Sirt1, a nicotinamide adenine dinucleotide ($NAD^+$)-dependent histone deacetylase, is known to deacetylate a number of proteins that are involved in various cellular pathways such as the stress response, apoptosis and cell growth. Modulation of the stress response by Sirtuin 1 (Sirt1) is achieved by the deacetylation of key proteins in a cellular pathway, and leads to a delay in the onset of cancer or aging. In particular, Sirt1 is known to play an important role in maintaining genomic stability, which may be strongly associated with a protective effect during tumorigenesis and during the onset of aging. In these studies, Sirt1 was generated in stably expressing cells and during the stimulation of DNA damage to examine whether it promotes survival. Sirt1 expressing cells facilitated the repair of DNA damage induced by either ionizing radiation (IR) or bleomycin (BLM) treatment. Fastened damaged DNA repair in Sirt1 expressing cells corresponded to prompt activation of Chk2 and ${\gamma}$-H2AX foci formation and promoted survival. Inhibition of Sirt1 enzymatic activity by a chemical inhibitor, nicotinamide (NIC), delayed DNA damage repair, indicating that promoted DNA damage repair by Sirt1 functions to induce survival when DNA damage occurs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.969-973
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• 2013

To simulate the effect of high dose-rate radiation on semiconductor devices, device modeling work has been performed especially in the area of photo-current generation by a PIN diode. The resultant analytical values were compared with experimental ones that were specially designed and performed to benchmark the simulation results. Initial results showed 27.85% error between the simulation and the experiment. The error can be further reduced by improvement both in simulation and in related experiments. The developed technique from the study can be applicable to radiation dosimetry and to analysis on the radiation effects in electronics.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.227-231
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• 1993

The role of ascorbate as an antioxidant in the prevention and cure of disease that result from free radicals has been of considerable interest and controversy lately. As an antioxidant, we can expect it to protect against radiation damage caused by free radicals that are produced when radiation, especially sparsely ionizing radiation, interacts with living tissues. The plasma and whole blood concentration of ascorbate was analyzed before and just after the radiation therapy for the purpose of estimating the consumption amount of ascorbate during radiotherapy. Whole blood ascorbate was decreased from 1.82 mg/dl to 1.58 mg/dl, plasma ascorbate was decreased from 1.13 mg/dl to 1.08 mg/dl, and urine ascorbate was decreased from 9.33 mg/dl to 6.96 mg/dl after radiotherapy. Although the difference was not significant statistically, further human study should be followed to define the role of ascorbate as a radioprotector.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2229-2236
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• 2021

In nuclear-related facilities, such as nuclear power plants, research reactors, accelerators, and nuclear waste storage sites, radiation detection, and mapping are required to prevent radiation overexposure. Sensor network systems consisting of radiation sensor interfaces and wxireless communication units have become promising tools that can be used for data collection of radiation detection that can in turn be used to draw a radiation map. During data collection, malfunctions in some of the sensors can occasionally occur due to radiation effects, physical damage, network defects, sensor loss, or other reasons. This paper proposes a reproduction strategy for radiation maps using a U-net model to compensate for the loss of radiation detection data. To perform machine learning and verification, 1,561 simulations and 417 measured data of a sensor network were performed. The reproduction results show an accuracy of over 90%. The proposed strategy can offer an effective method that can be used to resolve the data loss problem for conventional sensor network systems and will specifically contribute to making initial responses with preserved data and without the high cost of radiation leak accidents at nuclear facilities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.657-663
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• 2015

Ionizing radiation induces cell damage through formation of reactive oxygen species. The present study was designed to evaluate the protective effects of post-treatment with hesperetin against ${\gamma}$-irradiation-induced cellular damage and oxidative stress in BALB/c mice. Healthy female BALB/c mice were exposed to ${\gamma}$-irradiation and administered hesperetin (25 mg/kg and 50 mg/kg, b.w., orally) for 7 days after 6 Gy of ${\gamma}$-irradiation. Exposure to ${\gamma}$-irradiation resulted in hematopoietic system damage manifested as decreases in spleen indexes and WBC count. In addition, hepatocellular damage characterized by increased levels of aspartate aminoransferase (AST) and alanine aminotransferase (ALT) in plasma. However, post-irradiation treatment with hesperetin provided significant protection against hematopoietic system damage and decreased AST and ALT levels in plasma. The results indicate that ${\gamma}$-irradiation induced increases in lipid peroxidation and xanthine oxidase (XO) as well as decreases in antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and glutathione (GSH) in the liver. These effects were also attenuated by post-treatment with hesperetin, which decreased lipid peroxidation and XO as well as increased antioxidant enzymes and GSH. These results show that post-treatment with hesperetin offers protection against ${\gamma}$-irradiation-induced tissue damage and oxidative stress and can be developed as an effective radioprotector during radiotherapy.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.509-516
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• 2014

Radiation therapy for variety of human solid tumors utilizes mechanism of cell death after DNA damage caused by radiation. In response to DNA damage, cytochrome c was released from mitochondria by activation of pro-apoptotic Bcl-2 family proteins, and then elicits massive $Ca^{2+}$ release from the ER that lead to cell death. It was also suggested that irradiation may cause the deregulation of $Ca^{2+}$ homeostasis and trigger programmed cell death and regulate death specific enzymes. Thus, in this study, we investigated how cellular $Ca^{2+}$ metabolism in RKO cells, in comparison to radiation-resistant A549 cells, was altered by gamma (${\gamma}$)-irradiation. In irradiated RKO cells, $Ca^{2+}$ influx via activation of NCX reverse mode was enhanced and a decline of $[Ca^{2+}]_i$ via forward mode was accelerated. The amount of $Ca^{2+}$ released from the ER in RKO cells by the activation of $IP_3$ receptor was also enhanced by irradiation. An increase in $[Ca^{2+}]_i$ via SOCI was enhanced in irradiated RKO cells, while that in A549 cells was depressed. These results suggest that ${\gamma}$-irradiation elicits enhancement of cellular $Ca^{2+}$ metabolism in radiation-sensitive RKO cells yielding programmed cell death.