• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.109.1-109.1
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• 2003

The aim of this study was to investigate the biological effects of blood and testis by neutron or gamma-ray irradiation in black mouse. Six-week-old C57BL male mice were irradiated with neutron (flux: 1.036739E+09) or Co60 gamma rays(dose rate: lGy/min.) The irradiation method of animal was abdominal irradiation and dose of irradiation was 10 and 20 Gy added with 5 and 15Gy in neutron irradiation.. After that, the mice were sacrificed 3 days later. Blood and testis were taken and then composition of blood in blood cell were investigated. (omitted)

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권6호
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• pp.617-621
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• 2013

This study examined the effect of electron-beam (E-beam) irradiation on the electrical properties of n-GaN, AlGaN and AlGN/GaN structures on sapphire substrates. E-beam irradiation resulted in a significant decrease in the gate leakage current of the n-GaN, AlGaN and HEMT structure from $4.0{\times}10^{-4}A$, $6.5{\times}10^{-5}A$, $2.7{\times}10^{-8}A$ to $7.7{\times}10^{-5}A$, $7.7{\times}10^{-6}A$, $4.7{\times}10^{-9}A$, respectively, at a drain voltage of -10V. Furthermore, we also investigated the effect of E-beam irradiation on the AlGaN surface in AlGaN/GaN heterostructure high electron mobility transistors(HEMTs). The results showed that the maximum drain current density of the AlGaN/GaN HEMTs with E-beam irradiation was greatly improved, when compared to that of the AlGaN/GaN HEMTs without E-beam irradiation. These results strongly suggest that E-beam irradiation is a promising method to reduce leakage current of AlGaN/GaN HEMTs on sapphire through the neutralization the trap.

• Preventive Nutrition and Food Science
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• 제8권2호
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• pp.191-195
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• 2003

We investigated the effects of gamma irradiation on the microbiological, chemical and sensory qualities of bulgogi, a traditional Korean meat product. Gamma irradiation reduced the number of coliform bacteria and bacterial colonies counted in Salmonella-Shigella selective agar to a non-detectable level. Thermophillic microorganisms (mainly Bacillus spp.) in bolgogi refrigerated for 20 days were also significantly reduced by 3 log cycles by 2.5 to 7.5 kGy of irradiation, compared to the control. Electron donating ability and shear force of ready-to-cook bulgogi was not significantly affected by gamma irradiation. Irradiation increased the 2-thiobarbituric acid reactive substances (TBARS) value. The irradiated, raw, ready-to-cook bulgogi had significantly higher scores in color and appearance than those of non-irradiated controls from sensory evaluation. The overall acceptance of cooked bulgogi had higher scores in non-irradiated or 2.5 kGy-irradiated bulgogi than the 5.0- or 7.5-kGy irradiated counterparts. In conclusion, irradiation at 2.5 kGy is recommended as a method to improve shelf-life, safety, and to achieve acceptable quality of ready-to-cook bulgogi without any adverse changes in the sensory characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.514-515
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• 2008

Low level laser therapy has various therapy effects. This paper performed the basic study for developing the Low Level Laser Therapy Equipment for medical treatment. The apparatus has been fabricated using the laser diode and microprocessor unit. This equipment was fabricated using a micro-controller and a laser diode, and designed to enable us to control light time, frequency and so on. In this study, the designed device was used irradiation to find out how 850 nm laser diode affected the cell proliferation of RAT bone-marrow cells. Experiment was performed to irradiation group and non-irradiation group for Rat bone marrow 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 micro plate reader. As a result, the cell increase of Rat bone marrow 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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• 제35권3호
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• pp.133-139
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• 2005

Purpose To observe the histopathological changes in the periodontal tissues of mandibular molars in streptozotocin-induced diabetic rats after irradiation. Materials and Methods : The male Sprague-Dawley rats weighing approximately 250 gm were divided into four groups: control, diabetes, irradiation, and diabetes- irradiation groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control and irradiation groups were injected with citrate buffer only After 5days, the head and neck region of the rats in irradiation and diabetes-irradiation groups were irradiated with a single absorbed dose of 10Gy. All the rats were sacrificed at 3, 7, 14, 21, and 28 days after irradiation. The specimen including the mandibular molars were sectioned and observed using a histopathological method. Results In the diabetes group, osteoclastic activity was observed in the alveolar bone and the root throughout the period of experiment. Also, osteoblastic and fibroblastic activities were markedly decreased. In the irradiation group, the osteoclasts were observed in the alveolar bone and the dilated capillaries were increased in the early experimental phases. However, vigorous osteoblastic activity was noted in the late experimental phases. In the diabetes-irradiation group, osteoblastic activity in the alveolar bone and the root was observed in the early experimental phases. However, there were no resorption and osteoblastic activity in the alveolar bone and the root in the late experimental phases, and obvious atrophic change of fibrous tissues was noted. Conclusion : This experiment suggests that osteoblastic activity was caused by irradiation in the late experimental phases, but atrophic change of the periodontal ligament tissues was induced after irradiation in diabetic state.

• Preventive Nutrition and Food Science
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• 제6권2호
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• pp.91-95
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• 2001

Competitive indirect enzyme linked immunosorbent assay (Ci-ELISA) was used to obtain the preliminary data for the detection of irradiated beef. Ci-ELISA was individually formatted with polyclonal antibodies produced from 2 kinds of bovine proteins, myosin and bovine serum albumin (BSA). Beef round, loin and tender loin were vacuum-packaged and subdivided into 3 groups of 1) irradiation; 2) irradiation and chilled at 4$^{\circ}C$ for 7 day; 3) irradiation and frozen at 2$0^{\circ}C$ for 2 months to observe the changes under different storage and/or distribution conditions. Irradiation was performed at 3, 5 and 7 kGy. Protein solutions prepared from the sample were tested by formatted Ci-ELISA. Detected concentrations of myosin and BSA decreased with the increased irradiation dose in all samples with different reduction rates. Myosin was more susceptible to freezing than BSA. Samples irradiated at 5 kGy or above could be differentiated from non-irradiated ones by Ci-ELISA. These results indicate that immunological assay can be used as a detection method for irradiated beef.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.243-248
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• 1999

Ultrasonic wave technology was employed to improve filtration performance and ethanol production in a bioreactor equipped with an internal ceramic-membrane filter module. The filtration performance was found to depend on the power and the pattern of ultrasonic wave irradiation. Under the optimized conditions (irradiation time: 25 see, period: 5 min, and ultrasonic power: 60 W), the flux was improved with the periodic-pause method by 200-700％ compared with the control (with no irradiation), while the improvement was only 30 to 90％ without the periodic-pause method. The final ethanol concentration also increased slightly. However, in a more severe condition (irradiation time: 2.5 min, period: 5 min, and ultrasonic power: 110 W), the irradiation of ultrasonic waves was observed to disturb cell integrity and viability, and thus to decrease ethanol production.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4226-4230
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• 2022

The Korea Atomic Energy Research Institute (KAERI) has designed a Hybrid-Low Power Research Reactor (H-LPRR) which can be used for critical assembly and conventional research reactor as well. It is an open tank-in-pool type research reactor (Thermal Power: 50 kW_th) of which the most important applications are Neutron Activation Analysis (NAA), Radioisotope (RI) production, education and training. There are eight irradiation holes on the edge of the reactor core: IR (6 holes for RI production) and NA (2 holes for NAA) holes. In order to quantify the elemental concentration in target samples through the Instrumental Neutron Activation Analysis (INAA), it is necessary to measure neutron spectrum parameters such as thermal neutron flux, the deviation from the ideal 1/E epithermal neutron flux distribution (α), and the thermal-to-epithermal neutron flux ratio (f) for the irradiation holes. In this study, the MCNP6.1 code and FORTRAN 90 language are applied to determine the parameters for the two irradiation holes (NA-SW and NA-NW) in H-LPRR, and in particular its α and f parameters are compared to values of other research reactors. The results confirmed that the neutron irradiation holes in H-LPRR are designed to be sufficiently applied to neutron activation analysis, and its performance is comparable to that of foreign research reactors including the TRIGA MARK II.

• Imaging Science in Dentistry
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• 제35권1호
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• pp.9-14
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• 2005

Purpose : To observe the histopathological changes in the pulp tissues of mandibular molars in streptozotocin-induced diabetic rats after irradiation. Materials and Methods : The male Sprague-Dawley rats weighing approximately 250 gm were divided into four groups: control, diabetes, irradiation, and diabetes-irradiation groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in control and irradiation groups were injected with citrate buffer only. After 5 days, the head and neck region of the rats in irradiation and diabetes-irradiation groups were irradiated with a single absorbed dose of 10 Gy. All the rats were sacrificed at 3, 7, 14, 21, and 28 days after irradiation. The specimen including the mandibular molars were sectioned and observed using a histopathological method. Results : In the diabetes group, capillary dilatation was observed. However, there was no obvious morphologic alteration of the odontoblasts. In the irradiation group, generalized necrosis of the dental pulp tissues was observed. Vacuolation of the odontoblasts and dilatation of the capillaries were noted in the early experimental phases. In the diabetes-irradiation group, generalized degeneration of the dental pulp tissues was observed. Vacuolation of the dental pulp cells and the odontoblasts was noted in the late experimental phases. Conclusion : This experiment suggests that dilatation of the capillaries in the dental pulp tissues is induced by diabetic state, and generalized degeneration of the dental pulp tissues is induced by irradiation of the diabetic group.

• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.760-765
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• 2008

Low power laser therapy is internationally certified and is known to be effective in stimulating DNA in living organisms, increasing protein synthesis and activating cell division, smoothing blood circulation, promoting cell activation, cell regeneration and function. It also has anti-inflammatory, anti-edemic, anti-fibrous dysplastic and neuralogic hyperfunctional effects. This study was intended to verify the effect of LED irradiation therapy on wound healing in cell and animal tests by applying LED irradiator using a laser and laser diode, which was independently designed and developed to emit beams of similar wavelength to that of a laser. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity and reservation. In case of cell proliferation experiment, each experiment was performed to irradiation group and non-irradiation group for 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 micro-plate reader. In the wound healing experiment, 1$cm^2$ wounds on the skin wound of SD-Rat(Sprague-Dawley Rat) were made. Light irradiation group and none light irradiation group divided, each group was irradiated one hour a day for 9 days. As a result, the cell increase of tissue cells was verified in irradiation group as compared to non-irradiation group. And, compared with none light irradiation group, the lower incidence of inflammation and faster recovery was shown in light irradiation group.