• Journal of radiological science and technology
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• v.38 no.4
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• pp.365-374
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• 2015

The regular quality assurance (RQA) of X-ray images is essential for maintaining a high accuracy of diagnosis. This study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) of a computed radiography (CR) system for various periods of use from 2006 to 2015. We measured the pre-sampling MTF using the edge method and RQA 5 based on commission standard international electro-technical commission (IEC). The spatial frequencies corresponding to the 50% MTF for the CR systems in 2006, 2009, 2012 and 2015 were 1.54, 1.14, 1.12, and $1.38mm^{-1}$, respectively and the10% MTF for 2006, 2009, 2012, and 2015 were 2.68, 2.44, 2.44, and $2.46mm^{-1}$, respectively. In the NPS results, the CR systems showed the best noise distribution in 2006, and with the quality of distributions in the order of 2015, 2009, and 2012. At peak DQE and DQE at $1mm^{-1}$, the CR systems showed the best efficiency in 2006, and showed better efficiency in order of 2015, 2009, and 2012. Because the eraser lamp in the CR systems was replaced, the image quality in 2015 was superior to those in 2009 and 2012. This study can be incorporated into used in clinical QA requiring performance and evaluation of the performance of the CR systems.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.451-461
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• 2015

In megavoltage (MV) radiotherapy, delivering the dose to the target volume is important while protecting the surrounding normal tissue. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using an edge block in megavoltage X-ray imaging (MVI). We used an edge block, which consists of tungsten with dimensions of 19 (thickness) ${\times}$ 10 (length) ${\times}$ 1 (width) $cm^3$ and measured the pre-sampling MTF at 6 MV energy. Various radiation therapy (RT) devices such as TrueBeam$^{TM}$ (Varian), BEAMVIEW$^{PLUS}$ (Siemens), iViewGT (Elekta) and Clinac$^{(R)}$iX (Varian) were used. As for MTF results, TrueBeam$^{TM}$(Varian) flattening filter free(FFF) showed the highest values of $0.46mm^{-1}$ and $1.40mm^{-1}$ for MTF 0.5 and 0.1. In NPS, iViewGT (Elekta) showed the lowest noise distribution. In DQE, iViewGT (Elekta) showed the best efficiency at a peak DQE and $1mm^{-1}DQE$ of 0.0026 and 0.00014, respectively. This study could be used not only for traditional QA imaging but also for quantitative MTF, NPS, and DQE measurement for development of an electronic portal imaging device (EPID).

• Journal of Life Science
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• v.19 no.11
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• pp.1629-1636
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• 2009

Pine trees (Pinus densiflora Sieb. et Zacc.) have been used as a traditional health-promoting medicinal food in Korea. This research was performed to determine the antioxidative and antibacterial activities, tyrosinase, nitric oxide synthesis, angiotensin converting enzyme (ACE), and xanthine oxidase inhibition effects of the pine bud ethanol extract (PBE). Antioxidative activities of PBE were measured by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging activity and superoxide dismutase-like activity (SODA). DPPH radical scavenging and SOD-like activities of PBE were remarkably increased in a dose-dependent manner, and were about 88.9% and 47.9% at 1 mg/ml and 10 mg/ml, respectively. The xanthine oxidase and angiotensin converting enzyme activities were inhibited about 71.9% and 60.8% at 1 mg/ml and $100{\mu}g/ml$ of PBE, respectively. The tyrosinase inhibitory activities of PBE were slightly increased in a dose-dependent manner. The PBE showed strong antimicrobial activities on Escherichia coli (E. coli) and Vibrio paraheamolyticus. Stimulation of the macrophages RAW264.7 cells with lipopolysaccharide (LPS) resulted in increased production of nitric oxide (NO) in the medium. However, NO synthesis was reduced up to 54% by addition of PBE at $200{\mu}g/ml$. These results revealed that pine buds have a strong antioxidative and anti-inflammatory activity, and exhibit angiotensin converting enzyme and xanthine oxidase inhibitory activities. This suggests that pine buds have the greatest property as a source for natural health products.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.131-139
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• 2014

The aim of this study was to manufacture Cutting-Gouda cheese and to investigate the change in physicochemical properties of Cutting-Gouda cheese made with Lactobacillus rhamnosus_p1. Lactic acid bacteria were isolated from Gouda cheese ripened for more than 1 year. They were identified as 2 strains of L. rhamnosus, Lactobacillus casei, Lactobacillus curvatus, and Staphylococcus saprophyticus by 16S rDNA sequencing and named L. rhamnosus_p1, L. casei_p2, L. curvatus_p3, L. rhamnosus_p4 and S. saprophyticus_p5. The proteolytic activities of isolated strains against casein were measured using prepared skim milk agar plates. L. rhamnosus_p1 showed the highest proteolytic activity. Cutting-Gouda cheese was made with L. rhamnosus_p1, and its physicochemical properties (moisture, protein, fat, ash and free amino acid content) were measured during ripening periods. Because of the modified atmosphere packaging ($N_2{^-}$), there was no change in moisture, protein, fat, and ash in the experimental group. The total amount of free amino acids in the control and experimental group gradually increased during ripening periods. The sensory evaluation showed that the experimental group was preferable to the control group. This result suggests that L. rhamnosus_p1 has potential to be developed as a new starter for Gouda cheese.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.99-105
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• 2016

The noise power spectrum (NPS) is one of the most general methods for measuring the noise amplitude and the quality of an image acquired from a uniform radiation field. The purpose of this study was to compare different NPS methodologies by using megavoltage X-ray energies. The NPS evaluation methods in diagnostic radiation were applied to therapy using the International Electro-technical Commission standard (IEC 62220-1). Various radiation therapy (RT) devices such as TrueBeam$^{TM}$(Varian), BEAMVIEW$^{PLUS}$(Siemens), iViewGT(Elekta) and Clinac$^R$ iX (Varian) were used. In order to measure the region of interest (ROI) of the NPS, we used the following four factors: the overlapping impact, the non-overlapping impact, the flatness and penumbra. As for NPS results, iViewGT(Elekta) had the higher amplitude of noise, compared to BEAMVIEW$^{PLUS}$ (Siemens), TrueBeam$^{TM}$(Varian) flattening filter, Clinac$^{R}$iXaS1000(Varian) and TrueBeam$^{TM}$(Varian) flattening filter free. The present study revealed that various factors could be employed to produce megavoltage imaging (MVI) of the NPS and as a baseline standard for NPS methodologies control in MVI.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.633-638
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• 2017

The amount of radioactive waste has been rapidly increased with development of radiation treatment in medical field. Recently, it has been a common practice to use I-131 for thyroid cancer, F-18 for PET/CT and Tc-99m for diagnosis of nuclear medicine. All the wastes concerned have been disposed of by means of the self-disposal method, for example incineration, after storage enough to decay less than clearance level. IAEA proposed criteria for clearance level of waste which depends on the individual ($10{\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). In this study, specific radioactivity of radioactive waste contaminated with Re-186 was measured to confirm whether it meets the clearance level. Re-186 has long half life of 3.8 days relatively and emits beta and gamma radiation, therefore it can be applied in treatment and imaging purposes. The specific radioactivity of contaminated gloves weared by radiation workers was measured by MCA(Multi-channel Analyzer) which was calibrated by reference materials in accordance with the measuring procedure. As a result, comparison evaluation of decay storage period between the half-life which was calculated by attenuation curve based on real measurement and physical half-life was considered, and it is showed that the physical half-life is longer than induced half-life. Therefore, the storage period of radioactive waste for self-disposal may be curtailed in case of application of induced half-life. The result of this study will be proposed as ISO standard.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.86-92
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• 2022

Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user's walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.

• Korean Journal of Environment and Ecology
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• v.36 no.3
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• pp.303-317
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• 2022

Climate change caused by increased greenhouse gas emissions can alter the natural ecosystem, including the pollination ecosystem and agricultural ecology, which are ecological interactions between potted insects and plants. Many studies have reported that populations of wild bees, including bees and wasps (BW), which are the key pollinators, have gradually declined due to climate change, leading to adverse impacts on overall biodiversity, ultimately with agribusinesses and the life cycle of flowering plants. Therefore, we could infer that the rising temperature in Korean Peninsula (South Korea) due to global warming has led to climate change and influenced the wild bee's ecosystem. In this study, we surveyed the distributional pattern of BW (Superfamily: Apoidea, Vespoidea, and Chrysidoidea) at 51 sites from 2017 (37 sites) to 2018 (14 sites) to examine the effects of climatic factors on the nationwide distribution of BW in South Korea. Previous literature has confirmed that their distribution according to forest climate zones is significantly correlated with mean and accumulative temperatures. Based on the result, we predicted the effects of future climate changes on the BW distribution that appeared throughout South Korea and the species that appeared in specific climate zones using Shared Socioeconomic Pathways (SSPs). The distributions of wild BW predicted by the SSP scenarios 2-4.5 and 5-8.5 according to the BIOMOD species distribution model revealed that common and endemic species will shift northward from the current habitat distribution by 2050 and 2100, respectively. Our study implies that climate change and its detrimental effect on the ecosystem is ongoing as the BW distribution in South Korea can change, causing the change in the ecosystem in the Korean Peninsula. Therefore, immediate efforts to mitigate greenhouse gas emissions are warranted. We hope the findings of this study can inspire further research on the effects of climate change on pollination services and serve as the reference for making agricultural policy and BW conservation strategy

• Journal of Nutrition and Health
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• v.48 no.6
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• pp.476-487
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• 2015

Purpose: This study was conducted to examine the concentration of nutrients in transitional breast milk from Korean lactating mothers and to evaluate daily intakes of their infants based on the Dietary Reference Intakes for Koreans 2010 (KDRIs 2010). Methods: Breast milk samples were collected at 5~15 days postpartum from 100 healthy lactating Korean mothers. Macro- and micro-nutrients, and immunoglobulin (Igs) concentrations in breast milk were analyzed. Results: The mean energy, protein, fat, and carbohydrate concentrations in breast milk were $59.99{\pm}8.01kcal/dL$, $1.47{\pm}0.27g/dL$, $2.88{\pm}0.89g/dL$, and $6.72{\pm}0.22g/dL$. The mean linoleic acid (LA), a-linolenic acid (ALA), arachidonic acid (AA), and docosahexaenoic acid (DHA) concentrations were $181.44{\pm}96.41mg/dL$, $28.15{\pm}8.89mg/dL$, $5.67{\pm}1.86mg/dL$, and $5.74{\pm}2.57mg/dL$. The mean vitamin A, vitamin D, vitamin E, vitamin $B_1$, vitamin $B_2$, vitamin $B_{12}$, and folate concentrations were $2.75{\pm}1.75{\mu}g/dL$, $2.31{\pm}1.12ng/dL$, $0.74{\pm}1.54mg/dL$, $3.02{\pm}1.84mg/dL$, $7.51{\pm}20.96{\mu}g/dL$, $61.78{\pm}26.78{\mu}g/dL$, $63.71{\pm}27.19ng/dL$, and $0.52{\pm}0.26{\mu}g/dL$. The mean concentrations of calcium, iron, potassium, sodium, zinc, and copper were $20.71{\pm}3.34mg/dL$, $0.59{\pm}0.86mg/dL$, $66.71{\pm}10.35mg/dL$, $27.72{\pm}10.16mg/dL$, $0.44{\pm}0.41mg/dL$, and $70.48{\pm}30.41{\mu}g/dL$. The mean IgA and total IgE concentrations were $61.85{\pm}31.97mg/dL$ and $235.00{\pm}93.00IU/dL$. The estimated daily intakes of infants for protein, vitamin D, vitamin E, vitamin $B_2$, vitamin $B_{12}$, iron, potassium, sodium, zinc, and copper were sufficient compared to KDRIs 2010 adjusted by transitory milk intakes. The estimated infants' intakes of energy, fat, carbohydrate, vitamin A, vitamin C, vitamin $B_1$, folate, and calcium did not meet KDRIs 2010 adjusted by transitory milk intakes. Conclusion: In general most estimated nutrient intakes of Korean breast-fed infants in transitory breast milk were sufficient, however some nutrient intakes were not sufficient based on KDRIs 2010. These results warrant conduct of future studies for investigation of important dietary factors associated with nutrients in breast milk to improve the quality of breast milk, which may contribute to understanding nutrition in early life and promoting growth and development of breast-fed infants.

• Journal of Nutrition and Health
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• v.42 no.5
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• pp.423-433
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• 2009

Folate and vitamin $B_{12}$ are essential cofactors for homocysteine (Hcy) metabolism. Homocysteinemia has been related with cardiovascular and neurodegenerative disease. We examined the effect of folate and/or vitamin $B_{12}$ deficiency on biomarkers of one carbon metabolism in blood, liver and brain, and analyzed the correlation between vitamin biomarkers in mild and moderate homocysteinemia. In this study, Sprague-Dawley male rats (5 groups, n = 10) were fed folatesufficient diet (FS), folate-deficient diet (FD) with 0 or 3 g homocystine (FSH and FDH), and folate-/vitamin $B_{12}$-deficient diet with 3 g homocystine (FDHCD) for 8 weeks. The FDH diet induced mild homocysteinemia (plasma Hcy 17.41 ${\pm}$ 1.94 nmol/mL) and the FDHCD diet induced moderate homocysteinemia (plasma Hcy 44.13 ${\pm}$ 2.65 nmol/mL), respectively. Although liver and brain folate levels were significantly lower compared with those values of rats fed FS or FSH (p < 0.001, p < 0.01 respectively), there were no significant differences in folate levels in liver and brain among the rats fed FD, FDH and FDHCD diet. However, rats fed FDHCD showed higher plasma folate levels (126.5 ${\pm}$ 9.6 nmol/L) compared with rats fed FD and FDH (21.1 ${\pm}$ 1.4 nmol/L, 22.0 ${\pm}$ 2.2 nmol/L)(p < 0.001), which is the feature of "ethyl-folate trap"by vitamin $B_{12}$ deficiency. Plasma Hcy was correlated with hepatic folate (r = -0.641, p < 0.01) but not with plasma folate or brain folate in this experimental condition. However, as we eliminated FDHCD group during correlation test, plasma Hcy was correlated with plasma folate (r = -0.581, p < 0.01), hepatic folate (r = -0.684, p < 0.01) and brain folate (r = -0.321, p < 0.05). Hepatic S-adenosylmethionine (SAM) level was lower in rats fed FD, FDH and FDHCD than in rats fed FS and FSH (p < 0.001, p < 0.001 respectively) and hepatic S-adenosylhomocysteine (SAH) level was significantly higher in those groups. The SAH level in brain was also significantly increased in rats fed FDHCD (p < 0.05). However, brain SAM level was not affected by folate and/or vitamin $B_{12}$ deficiency. This result suggests that dietary folate- and vitamin B12-deficiency may inhibit methylation in brain by increasing SAH rather than decreasing SAM level, which may be closely associated with impaired cognitive function in nutritional homocysteinemia.