• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.423-423
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• 2009

Currently, lasers are one of the most popular light sources in use for medical treatment. Many studies on low power lasers are being done in cell culture or through animal tests and most report different findings, making it difficult to verify their true effects. There are shifts in trends of studies from laser and LED that are expensive and generate heat problem to LED that are economically effective and safe. Its near infrared rays can penetrate deep into skin or muscle, up to 23 cm, without causing thermal damage or impairing neighboring tissues. This study verified the performance and effectiveness of an LED irradiator that was designed to emit similar wavelengths to that of a laser and thus could be used instead of a low level laser therapy in experiments on animals. And then, each experiment was performed to irradiation group and non-irradiation group for NTacSam:SD tissue cells. MIT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of NTacSam:SD tissue cells was verified in irradiation group as compared to non-irradiation group. The fact that specific wavelength irradiation has an effect on cell vitality and proliferation is known through this study.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.92-97
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• 2007

This paper performed the basic study for developing the Photodynamic Therapy Equipment for medical treatment. We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 levels by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage. And then, each experiment was performed to irradiation group and non-irradiation group for both Rat bone marrow and Rat tissue cells. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590 nm transmittance of ELISA reader. As a result, the cell increase of Rat bone marrow and tissue cells was verified in irradiation group as compared to non-irradiation group. The fact that specific wavelength irradiation has an effect on cell vitality and proliferation is known through this study.

• Imaging Science in Dentistry
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• v.32 no.1
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• pp.1-10
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• 2002

Purpose: To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. Materials and Methods: In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. Results: In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. Conclusion: The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.1034-1039
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• 2010

Variation of formation potential of THM (THMFP) by chlorination of humic acid and characteristics of water quality with ${\gamma}$-ray irradiation were investigated, which were divided into two categories by the order of ${\gamma}$-ray irradiation and chlorination in water treatment process. The group A consisted of the ${\gamma}$-ray irradiation followed by chlorination process of humic acid, and the group B consisted of the chlorination followed by ${\gamma}$-ray irradiation process. The pH, ORP, $UV_{254}$, and DOC decreased rapidly with an increase in ${\gamma}$-ray irradiation of 3 kGy. while conductivity was little changed. Maximum degradation ratio of chloroform in THMs of group A was 82%, while that in group B was 69%. No brominated THMs were detected at high irradiation (>3 kGy). We found that group A water treatment process was more effective in lowering the THMFP than that of group B.

• Radiation Oncology Journal
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• v.6 no.2
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• pp.259-262
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• 1988

Splenic irradiation in chronic myelogenous leukemia is reserved for patients who have painful splenemegaly despite chemotherapy and/or inoperable splenomegaly because of huge size. The role of splenic irradiation is diminution of painful splenomegaly and indirect effect of splenic irradiation on unirradiated hematopoietic and lymphoreticular tissue such as reduction of leukocyte count and increase of hemoglobin level. We report on a useful clinical method for splenic irradiation in chronic myelogenous leukemia. We have used sonography as the tool of simulation. The portal size using modified method is smaller than the field size of conventional simulation, and so this method suggests that useful to irradiation of huge splenomegaly, effective shielding of critical organ and the downfall of complication during irradiation of spleen.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.155-159
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• 2006

To reveal effects of gamma-irradiation with various doses on the expressions of C4H and F5H genes, the transcription levels of OsC4HL and OsF5HL were investigated in leaves and stems of two rice cultivars, Ilpoombyeo and IR-29, after the irradiation with 5, 10, 50, or 100 Gy for 4 h. In overall pattern of 24 h after the irradiation, the transcription levels of the two genes increased with the increasing doses of radiation in the leaves of both cultivars, except that of OsC4HL in IR-29. However, in the stems, the transcription level of OsF5HL increased in Ilpoombyeo and decreased in IR-29 dose-dependently, while that of OsC4HL decreased in Ilpoombyeo with the increasing doses of radiation and remained constant in IR-29. When the expressions of OsC4HL and OsF5HL were investigated in a time-course after the irradiation with 100 Gy, they reached their highest levels in the leaves of both cultivars 5 hand 72 h after the irradiation, respectively. Therefore, we suggest that the expressions of OsC4HL and OsF5HL, which involved in the same phenylpropanoid pathway, are differentially regulated during the post-irradiation period, showing different cultivar and tissue specificity. Furthermore, the dose dependency of the gene expressions is also discussed immediately after the irradiation.

• Polymer(Korea)
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• v.34 no.5
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• pp.454-458
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• 2010

In this study, the microstructural changes in orthopaedic-grade ultra high molecular weight polyethylene (UHMWPE) were compartively investigated for six different gamma-irradiation methods. Compared with un-irradiation (UGI), conventional gamma-irradiation in air room temperature (AR) induced statistically significant increases of relative crystallinity and percent crosslinking in UHMWPE. Vacuum environment (VR) during gamma-irradiation significantly increased the percent crosslinking in UHMWPE. Vacuum extreme low temperature (V77) during gamma-irradiation induced no significant changes in both relative crystallinity and percent crosslinking of UHMWPE but the percent crosslinking of UHMWPE in VR and V77 was significantly larger than that in AR. Post-irradiation stabilization process significantly increased the relative crystallinity of UHMWPE in V77, and it also significantly increased the percent crosslinking of UHMWPE in AR and V77.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.43-53
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• 1997

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. For this study, cell surviving curves were obtained for mouse lymphoma YAC-1 cell line using semi automated MTT assay. 2, 4,6, 8, 10Gy were irradiated at a dose rate of 210cGy/rnin using /sup 60/Co Irradiator ALDORADO 8. After irradiation, YAC-1 cell lines(3×10⁴cells/ml) were exposed to bleomycin or cisplatin for 1 hour. The viable cells were determined for each radiation dose and/or each concentration of drug at the 4th day. And they were compared to control values. The obtained results were as follows : 1. The surviving curve with gentle slope was obtained after irradiation of 2, 4, 6, 8, 10 Gy on YAC-1 cell line. 2. The cytotoxicity of bleomycin or cisplatin was increased significantly at all concentration of 0.2㎍/ml, 2㎍/ml and 20㎍/ml on YAC-1 cell line (P<0.01). And the cytotoxicity of cisplatin was greater than that of bleomycin at all concentration on YAC-1 cell line (P<0.01). 3. There were no significant differences of surviving fractions among 4Gy, 6Gy and 8Gy after irradiation of each radiation dose with 2㎍/ml of bleomycin compared with irradiation only on YAC-1 cell line. 4. There was significant difference of surviving fraction between 2Gy and 10Gy after irradiation of each radiation dose with 2㎍/ml of cisplatin compared with irradiation only on YAC-1 cell line(P<0.05). 5. There were significant differences of surviving fractions between the groups of irradiation only and the groups of irradiation with 2㎍/ml of bleomycin or cisplatin at all doses of 2, 4, 6, 8 and 10Gy on YAC-1 cell line(P<0.05).

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1243-1251
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• 2020

Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He⁺ irradiation at room temperature and high temperature of 600 ℃, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.694-699
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• 2004

To evaluate combined effect of gamma irradiation and rosemary extract powder, hamburger steak was treated with 200 or 500 ppm of rosemary extract powder, or 200 ppm of butylated hydroxyanisole (BHA), gamma irradiation at the absorbed doses of 5, 10 and 20 k㏉, and stored at 5$^{\circ}C$ for 3 months. The content of TBARS of irradiated ready-to-eat hamburger steak after gamma irradiation was in order of : Control＞Rosemary 200＞BHA＞Rosemary 500. Gamma irradiation accelerated lipid oxidation and decreased sensory qualify. However, the combined treatment of the addition of rosemary extract powder and irradiation was helpful for retarding the oxidation process and improving tie sensory characteristics during storage. Gamma irradiation decreased hardness and increased redness (a value) of ready-to-eat hamburger steak.