• Korean Journal of Ecology and Environment
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• v.49 no.1
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• pp.22-30
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• 2016

Environmental changes exert harmful effects on organisms inhabiting coastal regions. These changes are also associated with reduced production in aquaculture farms. In this study, we investigated internal and external responses of two Bivalvia species (Crassostrea gigas and Mytilus galloprovincialis) in Gamak Bay under stressful environmental conditions in aquaculture farms. We investigated external responses such as weight, size, and environment exposure time, and analyzed the expression of the HSP70 gene. C. gigas HSP70 gene expression level was significantly high in the C3 aquaculture farm site, but the weight and size of C. gigas were high in the C2 aquaculture farm site. The response of C. gigas HSP70 mRNA was associated with the environmental exposure time in each aquaculture farm. Expression of M. galloprovincialis HSP70 gene was found to be significantly higher in the M2 aquaculture farm site than in the M1 site, whereas the weight of M. galloprovincialis was observed to be higher in the M1 site. The size and environmental exposure time of M. galloprovincialis were similar between M1 and M2 sites. In addition, HSP70 sequences of C. gigas and M. galloprovincialis showed high similarity with that of another marine species. According to our results, there were differences in internal responses following environmental stress in aquaculture farms, with respect to HSP70 gene expression. The results suggest that the HSP70 gene is a useful molecular indicator for monitoring stress responses in Bivalvia species in the field.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.50-53
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• 2019

Purpose Yttrium-90 (Y-90) is high-energy beta emitters ($E{\beta}$, max = 2.28 MeV) with the mean penetration depth of 2.5 mm in tissue. Radioactive microspheres containing Y-90 is widely used for the transarterial radioembolization of hepatocellular carcinoma. However, bremsstrahlung radiation from Y-90 can cause the external radiation exposure to medical staff who handle the Y-90 microspheres. In this study, shielding device for Y-90 microspheres was developed to minimize the external radiation exposure. Materials and Methods Y-90 microsphere shielding device was made from 6 mm thicknesses of tungsten including the lead glass window. Radiation shielding ability of Y-90 microsphere shielding device was evaluated using 4 GBq of $SIR-Spheres^{(R)}$ Y-90 microspheres. The bremsstrahlung radiation was measured using radiation survey meter. Results The mean radiation dose of Y-90 microspheres in acrylic shield was $261.7{\pm}2.3{\mu}Sv/h$ (n=5) at 10 cm away from the shield. With the additional tungsten shielding device, it was $23.7{\pm}1.3{\mu}Sv/h$ (n=5). Thus, the bremsstrahlung radiation dose was decreased by 90.9%. At 50 cm away from the shield, bremsstrahlung radiation was reduced by 89.2% after using tungsten shielding device. Conclusion During the preparation and radioembolization of Y-90 microsphere, medical staff are exposed to external radiation. In this study, we demonstrated that the use of tungsten shielding device devices significantly reduced the amount of bremsstrahlung radiation. Y-90 microsphere tungsten shielding device can be highly effective in reducing the bremsstrahlung radiation.

• Toxicological Research
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• v.29 no.2
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• pp.115-120
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• 2013

To investigate the effects of short-term exposure of beryllium on the human immune system, the proportion of T-lymphocytes such as CD3+, CD4+, CD8+, CD95, and NK cells, and the proportion of B cells and $TNF{\alpha}$ level in peripheral blood and immunoglobulins in the serum of 43 exposed workers and 34 healthy control subjects were studied. External exposure to beryllium was measured by atomic absorption spectrometer as recommended by the NIOSH analytical method 7300. T lymphocyte subpopulation analysis was carried out with flow cytometer. The working duration of exposed workers was less than 3 months and the mean ambient beryllium level was $3.4{\mu}g/m^3$, $112.3{\mu}g/m^3$, and $2.3{\mu}g/m^3$ in molding (furnace), deforming (grinding), and sorting processes, respectively (cited from Kim et al., 2008). However, ambient beryllium level after process change was non-detectable (< $0.1{\mu}g/m^3$). The number of T lymphocytes and the amount of immunoglobulins in the beryllium-exposed workers and control subjects were not significantly different, except for the total number of lymphocytes and CD95 (APO1/FAS). The total number of lymphocytes was higher in the beryllium-exposed individuals than in the healthy control subjects. Multiple logistic regression analysis showed lymphocytes to be affected by beryllium exposure (odd ratio = 7.293; p<0.001). These results show that short-term exposure to beryllium does not induce immune dysfunction but is probably associated with lymphocytes proliferation.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.44-50
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• 2013

Quantitative analyses of naturally occurring methanol were performed for the alcoholic beverages commonly consumed in Jecheon, Chungbuk province, South Korea. The headspace analysis method was optimized for the low and high alcoholic beverages. The external standard method was applied due to the overlapping of 2-propanol and 2-butanol (the internal standard candidates) with target sample matrix peaks. The target samples were selected based on the retail sales amounts of alcoholic beverages in the largest retailer food-mart chain, Jecheon, Chungbuk province, South Korea. There was no sample containing methanol over 0.5 $mg/m{\ell}$, the Korean maximum level of methanol in alcoholic beverages (1.0 $mg/m{\ell}$ for fruit originated liquor etc). The total exposure amount of methanol via alcoholic beverages was estimated based on the daily alcohol consumption of 40 g. The hazard indices calculated by methanol RfD 0.5 mg/kg bw day (US EPA) and ADI 20 mg/kg bw day (proposed by Lachenmeier etc.) were 0.301 and 0.008, respectively. As with the hazard index, aggregate exposures below a HI of 1.0 will likely not result in adverse noncancer health effects over a lifetime of exposure. Then the methanol exposure via the alcoholic liquours might not hazard to Jecheon citizen.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.4
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• pp.104-116
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• 2020

Fipronil, the phenylpyrazole insecticide, is effective and used in various fields. Especially, fipronil was reliable because it was known to be specific on invertebrate animals than vertebrate animals including mammals. However, fipronil had potential risks that affect vertebrate animals as it blocks the gamma-aminobutyric acid (GABA) receptors that also exists in vertebrates as well as invertebrates. Therefore, it was necessary that harmful effects of fipronil on vertebrates are clarified. For this purpose, the zebrafish (Danio rerio) were used on behalf of vertebrate animals in present study. The zebrafish were exposed to 5 ㎍/L, 25 ㎍/L, and 50 ㎍/L of fipronil during 12, 24 and 72 hours. To closely observe toxic process, 12 hours and 24 hours of additional time point were set in the exposure test. Nuclear magnetic resonance (NMR)-based metabolomics is an approach to detect metabolic changes in organism resulted from external stimuli. In this study, NMR-based metabolomics showed the metabolic changes in zebrafish caused by fipronil exposure. Metabolic analysis revealed that fipronil interfered with energy metabolism and decreased the antioxidant ability in zebrafish. Antioxidant ability decline was remarkable at high exposure concentration. In addition, metabolic analysis results over time suggested that reactions for alleviating the excessive nerve excitation occurred in zebrafish after fipronil exposure. Through this study, it was elucidated that the adverse effects of fipronil on vertebrate animals are evident. The risk of fipronil on vertebrates can be no longer ignored. Moreover, this study has a meaning of practically necessary research for organism by examining the effects of fipronil at low concentrations existed in real environment.

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.231-236
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• 2012

This study derived measures to reduce exposure doses by identifying factors which affect the external radiation dose rate of patients treated with radiopharmaceuticals for PET-CT tests. The external radiation dose rates were measured on three parts of head, thorax and abdomen at a distance of 50cm from the surface of 60 PET-CT patients. It showed there are changes in factors affecting the external radiation dose rate over time after the administration of F-18 FDG. The external radiation dose rate was lower in the patients with more water intake than those with less water intake before the injection of radiopharmaceuticals at all three points: right after the injection of radiopharmaceuticals (average 4.17 mins), after the pre-PEET-CT urination step (average 77.47 mins), and right after the PET-CT test (average 114.15 mins). The study also found there is a need to increase the amount of water intake before the injection of radiopharmaceuticals in order to maintain a low external radiation dose rate in patients. This strategy is only possible under the assumption that the quality of the video has not changed after conducting this study on the relations between the image and quality. This study also found a need to use radiopharmaceuticals with the minimum amount needed for each patient because F-FDG doses affects the external radiation dose rate at the point right after the injection of radiopharmaceuticals. Urination frequency was the most significant factor to affect the external radiation dose rates at the point right after the PET-CT test and the point after the pre-PET-CT urination step. There is a need to realize the strategy to increase the urination frequency of patients to maintain the external radiation dose rate low (average 77.47 mins) before and after the injection of radiopharmaceuticals. In addition, at this point, there is a need to take advantage of personal strategies because the external radiation dose rate is lower if the fasting time is shorter, the contrast medium is used, and the amount of water intake is increased after the administration of radiopharmaceuticals. Finally this study found the need to be able to generalize these findings through an in-depth research on the factors affecting the external radiation dose rate, which includes radiopharmaceutical dose, urination frequency, the amount of water intake, fasting time and the use of contrast medium.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2689-2693
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• 2014

The control over microstructure in block copolymer thin films using external electric fields has become an interesting research topic. In this article, the effect of nanoparticle on the microdomain alignments in block copolymer (polystyrene-b-poly(2-vinylpyridine)/nanoparticle (Au) thin films under electric fields has been examined with transmission electron microscopy. The homogeneous dispersion of Au nanoparticles into the block copolymer matrix was achieved by surface modification of nanoparticles with compatible ligands. Compared with the phenomenon seen in the pristine block copolymer thin films, a peculiar alignment behavior was observed in the block copolymer/nanoparticle hybrid thin films under electric fields. In addition, the different pathways observed in the pristine and nanoparticle incorporated block copolymer thin films were also monitored as a function of exposure time. This work can provide the fundamental information for understanding microdomain alignment in block copolymer/nanoparticle thin films under external electric fields.

• Journal of the Korean Magnetic Resonance Society
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• v.17 no.1
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• pp.1-10
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• 2013

Metabolomics is the study which detects the changes of metabolites level. Metabolomics is a terminal view of the biological system. The end products of the metabolism, metabolites, reflect the responses to external environment. Therefore metabolomics gives the additional information about understanding the metabolic pathways. These metabolites can be used as biomarkers that indicate the disease or external stresses such as exposure to toxicant. Many kinds of biological samples are used in metabolomics, for example, cell, tissue, and bio fluids. NMR spectroscopy is one of the tools of metabolomics. NMR data are analyzed by multivariate statistical analysis and target profiling technique. Recently, NMR-based metabolomics is a growing field in various studies such as disease diagnosis, forensic science, and toxicity assessment.

• Journal of Environmental Impact Assessment
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• v.14 no.5
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• pp.291-303
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• 2005

Impact pathway analysis(IPA) is a bottom-up approach to estimates health and environmental risks from emissions of classical pollutants (eg. $PM_{10}$, $SO_2$, $NO_x$ and CO). The model starts from the emission rates of facility, calculates the yearly mean concentrations of pollutants at the ground level using atmospheric dispersion models. After this, proper epidemiological exposure-response functions are applied to determine the impact on the receptors. Finally the methodology can monetise the calculated physical impact on the basis of selected economic evaluation. The aim of this study is to evaluate an external cost of virtual point source in Suwon area using IPA. The results shows minor modification of local input data can make it possible to apply the model to Suwon area.

• The Journal of Korean Society for Radiation Therapy
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• v.3 no.1
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• pp.11-18
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• 1989

Brachytherapy is known to be a good modality to achieve local control as a boost treatment following limited external irradiation, which may reduce the external beam related complication particularly in head and neck cancer. The authors developed iridium-192 ribbons recently to replace the radium needles in the field of brachytherapy. Total of 48 cases of head and neck and pelvic-perineal cancer patients had been treated with Ir-192 ribbons during last two years from October 1986 to September 1988, and the results were analyzed to assess the applicability of the fabricated sources. The conclusion is as follows; 1. Iridium implant resulted excellent tumor control effect in clinical application. 2. Iridium is superior than radium and cecium in brachytherapy because of easier to use and lesser exposure to the personnel. 3. Afterloading technique is useful to modify dose distribution, to expand treatment site and method, and to develop interstitial hyperthermia.