• Biomedical Science Letters
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• v.19 no.2
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• pp.98-104
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• 2013

Radiation is one of the major therapy for the removal of cancer cells. The results of the radiation therapy depend on the radio-resistance of cancer cells. For the effective treatment in these radio-resistant cancers, the use of chemicals that act on cancer cells is known to enhance the cytotoxic effects of radiation therapy. In this study, I investigated the effect of potassium cyanate (KCN) on the irradiated-colorectal cancer cell line, HCT 116 cells. KCN induces the carbamylation of proteins and can change the biological activity of various human cells. To understand the effect of KCN on the radiosensitivity of HCT 116 cells, I examined alteration of the cell cycle, generation of reactive oxygen species (ROS), cell viability, apoptosis and intracellular signaling proteins in the irradiated cells with/without KCN treatment. Combination treatment caused significant increase in sub $G_0/G_1$ and ROS generation in HCT 116 cells. KCN inhibited the proliferation and cell viability in irradiated HCT 116 cells. KCN-induced apoptosis of irradiated cells was processed via the activation of caspase 3 and caspase 9. Apoptosis-associated signal proteins, including Bax and Bcl-2 were regulated by irradiation with KCN treatment. Taken together, these results may indicate that KCN enhances the radiosensitivity of radio-resistant cell and then has a synergistic effect on radiation therapy in colorectal cancer.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.335-340
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• 2013

This study screened for radio-resistant strains lactic acid bacteria (LAB) by evaluating their capability to survive exposure to ionizing radiation. Ten strains of LAB - Lactobacillus bulgaricus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus delbruekii, Lactococcus lactis, Streptococcus thermophilus, Bifidobacterium breve, and Pediocuccos pentosaceus - were selected and subcultuted twice. The LAB was then further cultured for 3 d at $37^{\circ}C$ to reach 7-10 Log colony-forming units (CFU)/mL prior to irradiation and immediately exposed to gamma rays or electron beams with absorbed doses of 0, 1, 2, 3, 4, 5, 6, 8, and 10 kGy. Gamma irradiation gradually decreased the number of the tested viable LAB, and the effect was irradiation dose dependent. A similar effect was found in electron beam-irradiated LAB. Radiation sensitivity of LAB was calculated as $D_{10}$ values, which ranged from 0.26 kGy to 0.9 kGy and 0.5 kGy to 1.44 kGy with exposure to gamma and electron beam irradiation, respectively, in all tested LAB. L. acidophilus was the most resistant to gamma and electron beam irradiation, with $D_{10}$ values of 0.9 kGy and 1.44 kGy, respectively. These results suggest that L. acidophilus might be suitable for the preparation of probiotics as direct-fed microbes for astronauts in extreme space environments.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.178-179
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• 2003

The testis is composed of four cell types like supporting cells, steroid-producing cells, connective tissue cells and germ cells. Apoptosis is a common phenomenon during spormatogenesis. Apoptosis of germ cells can also be induced by exposure to radiation. Previous studies have shown that most types of germ cells are rather radiosensitive while somatic cells in testis are much more radio-resistant. The somatic cells in testis are divided to mainly Sertoli and Leydig cells. Though somatic cells are more radio-resistant than germ cells, radiation can induce the impairment of their function. This damaged function of somatic cells may accelerates degeneration of germ cell indirectly. Tn the present study, we have examined the apoptotic effect of mouse testis and irradiation effect of steroidogenesis of Leydig cells after irradiation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2685-2690
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• 2014

WPS determines position via a two-step process. In the construction phase, a radio map is constituted by collecting radio information signals. Positioning procedure is a step of comparing the radio signal newly acquired with the radio map. If the signals collected and the radio map are different the accuracy decreases. Even though the rate of accuracy is different according to positioning algorithms, accuracy drop is an issue common to all WPS systems. Signal strength fluctuation is caused by the malfunction of the device that receives positioning signals, obstruction and channel interference, etc. In this paper, in order to solve the problem caused by signal strength change, we propose a new radio map construction technique. The proposed method is intended to constitute a strong radio map to changes in the signal strength and updated by collecting the signal strength changes to the radio map. The use of this method is expected to enhance the accuracy of WPS by actively counteracting signal fluctuation.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.351-363
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• 2007

The scientific articles using radio labelled insecticides performed by Korean researchers were reviewed. The research works were divided into 4 categories such as soil, plant, animal and insect. All researches used $^{14}C$-labelled chemicals, and the $^{14}C$-carbofuran was widely used among them. Fate of insecticides, bound-residues and metabolic process were staple concerning area in soil study. And the uptake and translocation, metabolism and metabolites also a major interests in plant study. As well as the degradation, metabolic pathway and metabolites, and distribution of chemicals in animal tissue were another point of consideration in animal study. And finally, the penetration ratio into body and resistant mechanism were the major concerning views of study with insects.

• Journal of the Korea Furniture Society
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• v.17 no.1
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• pp.33-46
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• 2006

This study was carried out to investigate a radio-frequency/vacuum (RF/V) drying ability and physical properties of the green boards and the pre-kiln dried boards with 40 mm thickness, and the 70 mm-thick green board of Iroko (Milicia excelsa). The major results were summarized as follows; The drying time from initial moisture content (MC) of 110% to approximate 6% MC for a 40mm-thick green board was 192 hours, and about 200 hours for the 70 mm-thick green board, respectively and so the RF/V drying times were dramatically shortened compared to conventional kiln drying time. The case hardenings at the RF/V drying completion stage test were very negligible, thus represented almost no existence of the residual stress. The checks were very slightly formed on all of the boards during the RF/V drying test, but crook appeared quite severely. During the accelerating test, the water-resistant treated specimens had not experienced any signs of checking occurred, whereas the control boards had encountered very frequent occurrences of end checking and slight surface checking. There were no observations of warping and discoloring regardless of the treatment.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.583-590
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• 2020

Deinococcus actinosclerus BM2^T (GenBank: KT448814) is a radio-resistant bacterium that is newly isolated from the soil of a rocky hillside in Seoul. As an extremophile, D. actinosclerus BM2^T may possess anti-inflammatory properties that may be beneficial to human health. In this study, we evaluated the anti-inflammatory effects of BM2U, an aqueous extract of D. actinosclerus BM2^T, on lipopolysaccharide (LPS)-mediated inflammatory responses in RAW264.7 macrophage cells. BM2U showed antioxidant capacity, as determined by the DPPH radical scavenging (IC₅₀ = 349.3 ㎍/ml) and ORAC (IC₅₀ = 50.24 ㎍/ml) assays. At 20 ㎍/ml, BM2U induced a significant increase in heme oxygenase-1 (HO-1) expression (p < 0.05). BM2U treatment (0.2-20 ㎍/ml) significantly suppressed LPS-induced increase in the mRNA expression of proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 (p < 0.05). BM2U treatment also suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), which are involved in the production of inflammatory mediators. BM2U treatment also inhibited the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs): JNK, ERK, and p-38 (p < 0.05). Collectively, BM2U exhibited anti-inflammatory potential that can be exploited in attenuating inflammatory responses.

• International Journal of Oncology
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• v.56 no.6
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• pp.1540-1550
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• 2020

The epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), gefitinib, is an effective therapeutic drug used in the treatment of non-small cell lung cancers (NSCLCs) harboring EGFR mutations. However, acquired resistance significantly limits the efficacy of EGFR-TKIs and consequently, the current chemotherapeutic strategies for NSCLCs. It is, therefore, necessary to overcome this resistance. In the present study, the anticancer potential of natural extracts of Coptis chinensis (ECC) against gefitinib-resistant (GR) NSCLC cells were investigated in vitro and in vivo. ECC inhibited the viability, migration and invasion, and effectively induced the apoptosis of GR cells. These effects were associated with the suppression of EGFR/AKT signaling and the expression of anti-apoptotic proteins, Mcl-1 and Bcl-2, which were overexpressed in GR NSCLC cells. Combination treatment with ECC and gefitinib enhanced the sensitivity of GR cells to gefitinib in vitro, but not in vivo. However, ECC increased the survival of individual zebrafish without affecting the anticancer effect to cancer cells in vivo, which indicated a specific cytotoxic effect of ECC on cancer cells, but not on normal cells; this is an important property for the development of novel anticancer drugs. On the whole, the findings of the present study indicate the potential of ECC for use in the treatment of NSCLC, particularly in combination with EGFR-TKI therapy, in EGFR-TKI-resistant cancers.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.55-62
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• 1995

Plasma polymerization of Perfiuoropropene(PFP) and n-Hexane was carried out in a tubular type reactor by means of 13.56MHz radio frequency generator at the fixed RF discharge power of 25W and at the pressures of 100mTorr, 140mTorr and 200mTorr. The thin films were deposited on PAN fabrics in order to improve the dimemsional stability of woven states in hot water laundry. IR spectroscopy was used for the analysis of the structures of the thin films deposited and SEM for examination of surfaces of the fabrics. the PAN fabrics, which were coated by thin films at several experimental conditions, were immersed in boiling water for 2 hours and then the dimension stability of woven states were evaluated. In spite of very thin films, the results of surface modification were satisfactory. In general the performace of thin films by PFP was superior to that of n-Hexane.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.3
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• pp.85-92
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• 2015

SiC crystals are well known for their true potential as high power devices and their crystal growth activity is actively carried out in domestic as well as in abroad. Until now the process to grow this crystal has been done by sublimation technique using radio frequency induction heating method. However in order to get better quality of SiC crystals, the stability of temperature is needed because SiC crystal tends to transform to other polytypes. So, the possibility of SiC crytals growth was evaluated by different heating method. This study aimed to observe whether the resistant heating method would show stable growth and better quality of SiC single crystal than that of RF induction heating. As a result, polycrystalline SiC crystals were grown by the growth rate of 0.02~0.5 mm/hr under the condition of $2100{\sim}2300^{\circ}C$ at the bottom side of the crucible and 10~760 torr. The polycrystalline SiC crystals with 0.25 and 0.5 mm in thickness were grown successfully without seed and characterized by optical stereo microscopic observation.