• Journal of Pharmacopuncture
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• v.18 no.3
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• pp.68-74
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• 2015

Objectives: The present study was undertaken to determine the modulatory effect of taurine on the liver mitochondrial enzyme system with reference to mitochondrial lipid peroxidation (LPO), antioxidants, major tricarboxylic acid cycle enzymes, and electron transport chain enzymes during 7,12-dimethyl benz[a]anthracene (DMBA) induced breast cancer in Sprague-Dawley rats. Methods: Animals in which breast cancer had been induced by using DMBA (25 mg/kg body weight) showed an increase in mitochondrial LPO together with decreases in enzymic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST)), non-enzymic antioxidants (reduced glutathione (GSH), vitamin C, and vitamin E), in citric acid cycle enzymes (isocitrate dehydrogenase (ICDH), alpha ketoglutarate dehydrogenase (alpha KDH), succinate dehydrogenase (SDH) and malate dehydrogenase (MDH)), and in electron transport chain (ETC) complexes. Results: Taurine (100 mg/kg body weight) treatment decreased liver mitochondrial LPO and augmented the activities/levels of enzymic, and non-enzymic antioxidants, tricarboxylic acid cycle enzymes and ETC complexes. Conclusion: The results of our present study demonstrated the chemotherapeutic efficacy of taurine treatment for DMBA-induced breast carcinomas.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.286-290
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• 2016

Background: Activation of air and water in the electron linear accelerator for medical use has not been considered severely. By the new Japanese regulation for protection of radiation hazard, it became indispensable to evaluate of activation of air and water in the accelerator room. The measurement of induced activity in air and water components in the electron energy region of 10 to 20 MeV is very difficult, because this energy region is close to the threshold energy region of photonuclear reactions. Then, we measured the photonuclear reaction yields of $^{13}N$, $^{15}O$, and $^{11}C$ by using the electron linear accelerator. Obtained data were compared with the data calculated by the Monte Carlo method. Materials and Methods: An activation experiment was performed at the Research Center for Electron Photon Science, Tohoku University. Highly purified $SiO_2$, $Si_3N_4$, and carbon disks were irradiated for 10 minutes by bremsstrahlung converted by a tungsten plate. Induced activity from C, N, and O was obtained. Monte Carlo calculation was performed using MCNP5 and AERY (DCHAIN-SP) to simulate the experimental condition. Cross section data were adopted the KAERI dataset. Results and Discussion: In our experiment in hospital, calculated values were not agreed with experimental values. It might be three possible reasons as the cause of this deference, such as irradiation energy, calculation procedure and cross section data. Obtained data of this work, calculated and experimental values were good agreement with each other within one order. In this work, we used KAERI dataset of photonuclear reaction instead of JENDL. Therefore, it was found that the photonuclear cross section data of light elements are most important for yield calculation in these reactions. Conclusion: Further improvement for calculation using a new dataset JENDL/PD-2015 and considering electron energy spreading will be needed.

• Applied Microscopy
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• v.47 no.4
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• pp.226-232
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• 2017

Electron microscopy and X-ray diffraction have together played a key role in our understanding of the molecular structure and mechanism of contraction of muscle. This review highlights the role of electron microscopy, from early insights into thick and thin filament structure by negative staining, to studies of single myosin molecule structure, and finally to recent high-resolution structures by cryo-electron microscopy. Muscle filaments are designed for movement. Their labile structures thus present challenges to obtaining near-atomic detail, which are also discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.195.1-195.1
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• 2016

Currently, as Plasma application is expanded to the industrial and medical industrial, low temperature plasma applications became important. Especially in medical and biology, many researchers have studied about generated radical species in atmospheric pressure low temperature plasma directly adapted to human body. Therefore, so measurement their plasma parameter is very important work and is widely studied all around world. One of the plasma parameters is electron density and it is closely relative to radical production through the plasma source. some kinds of method to measuring the electron density are Thomson scattering spectroscopy and Millimeter-wave transmission measurement. But most methods have very expensive cost and complex configuration to composed of experiment system. We selected Michelson interferometer system which is very cheap and simple to setting up, so we tried to measuring electron density by laser interferometer with laser beam chopping module for measurement of temporal phase difference in plasma jet. To measuring electron density at atmospheric pressure Ar plasma jet, we obtained the temporal phase shift signal of interferometer. Phase difference of interferometer can occur because of change by refractive index of electron density in plasma jet. The electron density was able to estimate with this phase difference values by using physical formula about refractive index change of external electromagnetic wave in plasma. Our guiding laser used Helium-Neon laser of the centered wavelength of 632 nm. We installed chopper module which can make a 4kHz pulse laser signal at the laser front side. In this experiment, we obtained more exact synchronized phase difference between with and without plasma jet than reported data at last year. Especially, we found the phase difference between time range of discharge current. Electron density is changed from Townsend discharge's electron bombardment, so we observed the phase difference phenomenon and calculated the temporal electron density by using phase shift. In our result, we suggest that the electron density have approximately range between 1014~ 1015 cm-3 in atmospheric pressure Ar plasma jet.

• Progress in Medical Physics
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• v.26 no.3
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• pp.178-184
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• 2015

The Markus ionization chamber(R) is a small plane parallel ionization chamber widely used in clinical electron beam dosimetry. Plane parallel chambers were recommended for low energy electron dosimetry with the beam quality at $R_{50}<4.0g/cm^2$ (${\bar{E}}{\approx}10MeV$) according to TRS-398 protocol. However, the quality correction factors ($k_{Q,Q_0}$) of the Markus chamber was not presented in TRS-398 protocol for electron beam quality at $R_{50}<2.0g/cm^2$ (${\bar{E}}{\approx}4MeV$). In this study, the $k_{Q,Q_0}$ factors of the Markus chambers (PTW-34045) for beam qualities at $R_{50}=1.0$, 1.4, 2.0, 2.5, 3.0, and $5.0g/cm^2$ were determined by Monte Carlo calculations (DOSRZnrc/EGSnrc) and the dosimetric formalism of quality correction factor. The derived $k_{Q,Q_0}$ values were evaluated using the produced data based on TRS-398 and TG-51 protocols and known values for the Markus chamber.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4576-4582
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• 2023

The Korea retrospective dosimetry (KREDOS)-electron paramagnetic resonance (EPR) group undertook an intercomparison investigation utilizing hydroxyapatite. This analysis involved four institutions: the Korea Institute of Radiological and Medical Sciences, Dongnam Institute of Radiological and Medical Sciences, Korean Association for Radiation Application, and Radiation Health Institute of Korea Hydro & Nuclear Power. Following the irradiation of the hydroxyapatite sample, the recorded build-up was analyzed. To validate the reliability of the EPR dosimetry findings and enhance its operational performance, a hydroxyapatite dose-response curve was plotted and dosimetry was performed for a blind sample. The proficiency of each laboratory was assessed by employing an interlaboratory comparison methodology. This involved a comparative analysis of the measurement results by calculating the relative bias, z-score, and En value. The results submitted by the participating laboratories demonstrated satisfactory ratings for doses of 1.006, 3.999, and 6.993 Gy. Following the second intercomparison, efforts to optimize their hydroxyapatite-EPR dosimetry systems are underway in the participating laboratories. The current assessment of hydroxyapatite dose yielded the foundational data required to establish the parameters of dental dosimetry. In future, the third intercomparison experiment will be conducted for exploring other materials.

• Progress in Medical Physics
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• v.3 no.2
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• pp.59-65
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• 1992

Carcimoma of the breast are first frequency malignancy in women in the world. third frequency in Korea. Radiation therapy in breast cancer were treated through opposed tangential fields with photon beam or electron beam. Density within the field and thickness to tumor are very importent factors determining dose distribution in radiation therapy of electron beam. Radiotherapy traetment planning using computed tomography in Breast cancer are able to ideal dose distribution. Authors concluded as following. 6MeV energy of electron beam propered below 1.5cm in chest wall's thickness or internal mammary lymphnode's depth. 9MeV energy of electron beam from 1.5cm to 2.0cm. 12 MeV energy of electron beam from 2.0cm to 2.5cm.

• Journal of Radiation Protection and Research
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• v.47 no.3
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• pp.134-142
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• 2022

Background: This study investigated the characteristics of optically stimulated luminescence dosimeters (OSLDs) with fully filled deep electron/hole traps in the kV energy ranges. Materials and Methods: The experimental group consisted of InLight nanoDots, whose deep electron/hole traps were fully filled with 5 kGy pre-irradiation (OSLD_exp), whereas the non-pre-irradiated OSLDs were arranged as a control group (OSLD_cont). Absorbed doses for 75, 80, 85, 90, 95, 100, and 105 kVp with 200 mA and 40 ms were measured and defined as the unit doses for each energy value. A bleaching device equipped with a 520-nm long-pass filter was used, and the strong beam mode was used to read out signal counts. The characteristics were investigated in terms of fading, dose sensitivities according to the accumulated doses, and dose linearity. Results and Discussion: In OSLD_exp, the average normalized counts (sensitivities) were 12.7%, 14.0%, 15.0%, 10.2%, 18.0%, 17.9%, and 17.3% higher compared with those in OSLD_cont for 75, 80, 90, 95, 100, and 105 kVp, respectively. The dose accumulation and bleaching time did not significantly alter the sensitivity, regardless of the filling of deep traps for all radiation qualities. Both OSLD_exp and OSLD_cont exhibited good linearity, by showing coefficients determination (R²) > 0.99. The OSL sensitivities can be increased by filling of deep electron/hole traps in the energy ranges between 75 and 105 kVp, and they exhibited no significant variations according to the bleaching time.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.797-797
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• 2005

• 한국전자현미경학회:학술대회논문집
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• 2004.11a
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• pp.103-103
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• 2004