• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.779-795
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• 2002

Internet, a world wide network of computers, is considered as a sea of information because it allows people to share information beyond the barriors of time and space. However, in spite of the unmeasurable potential applications of the internet, its use in the field of biology education has been extremely limited mainly due to the scarcity of good biology-related sites. In order to provide useful guidelines for constructing user-friendly study sites, which can help high school students with different intellectual levels to study biology, comparative studies were performed on selected educational sites. Initially, hundreds of related sites were examined, and, subsequently, four distinct sites were selected not only because they are well organized, but also because each is unique in its contents. Also, a survey was carried out against the users of each site. The survey results indicated that the high school students regard the web-based biology study tools as effective teaching methods although there might be some bias in criteria for selecting target sites. In addition to the detailed biology topics and the related biology informations, multimedia data including pictures, animations and movies are found to be one of the important ingredients for desirable biology study sites. Thus, the inclusion of multimedia components should also be considered when developing a systematic biology study site. Overall, the role of the cyber space is expected to become more and more important. Since the development of the user-satisfied and self-guided sites require interdisciplinary collaborational efforts which should be made to promote extensive communication among teachers, education professionals, and computer engineers. Furthermore, the introduction of good biology study sites to the students by their teachers is also important factor for the successful web-based education.

• Progress in Medical Physics
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• v.25 no.1
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• pp.15-22
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• 2014

The IMRT is proper implement to get high dose deliver to tumor as its shape and selective approach in radiation therapy. Since the IMRT is performed as modulated the radiation fluence by the MLC created the open shapes and its irradiation time, the dose of segment of radiation field effects on the cumulated portal dose. The accurate output factor of small and step shape of segment is important to improve the determination of deliver tumor dose as it is directly proportional to dose. This experiment performed with the 6 MV photon beam of Clinac Ex(Varian) from $3{\times}3cm^2$ to $0.5{\times}0.5cm^2$ small field size for collimator jaw in MLC free and/or for MLC open field in fixed collimator jaw $10{\times}10cm^2$ using the CC01 ion chamber, SFD diode, diamond detector and X-Omat film dosimetry. As results of normalized to the reference field of $10{\times}10cm^2$ of MLC, the output factor of $3{\times}3cm^2$ showed $0.899{\pm}0.0106$, $0.855{\pm}0.0106$ for $2{\times}2cm^2$, $0.764{\pm}0.0082$ for $1{\times}1cm^2$ and $0.602{\pm}0.0399$ for $0.5{\times}0.5cm^2$. The output factor of MLC open field has shown a maximum 3.8% higher than that of the collimator jaw open field.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.363-368
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• 2015

Purpose: In this study, dominant eye is monitoring and level of dominant was measured in subjective and objective test. Methods: The average age of 21.08 years old of 129 adult (69 male, 60 female) who was no underlying ocular disease were participated in this study. dominant eye was determined by monocular instrument in subjecttive test and using a thin ring ($3.8cm{\times}3.8cm$) in objective test and level of dominant was measured direction of movement of the thin rim. Results: In the subjective test, there are 100 (77.52%) subjects whose dominant eye was right eye, and 29 (22.48%) subjects whose dominant eye was left eye. In the objective test, 90 (69.77%) subjects had right eye d and 33 (25.58%) subjects had left eye, as dominant eye, and 6 (4.65%) subjects had no dominant eye. Comparison of subjective test and objective test by dominant eye were equal in the 104 (80.62%) subjects, unequal in the 19 (14.73%) and center 6 (4.65%) subjects. The level of dominant eye in objective dominant eye test, there were middle 52 (57.78%) subjects, high 38 (42.22%) subjects in the right eye, and middle 25 (75.76%) subjects, high 8 (24.24%) subjects in the left eye. Conclusions: In this study O - Ring Test hasadvantage of direction and level of dominant eye, and middle or center dominant eye was shown in unequal. From this results, testing of dominant eye should be relationship equal and unequal, also required to be study in dominant eye level in binocular vision.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.56-61
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• 2018

In Bunsen reaction section for the integrated operation of sulfur-iodine (SI) process, $I_2$ and $H_2O$ reactants are supplied as dissolved species in an $HI_x$ solution. Most of the $H_2SO_4$ product is found in the $HI_x$ phase when Bunsen reaction is performed using the $HI_x$ solution and $SO_2$ feed, so that the volume ratio of the $H_2SO_4$ phase to the $HI_x$ phase is very low. In this study, we investigated the effects of ultrasound irradiation on Bunsen reaction using the $HI_x$ solution to improve its phase separation performance. With ultrasound irradiation, the amount of $H_2SO_4$ moved to the $H_2SO_4$ phase from the $HI_x$ phase increased by up to 58.0 mol% and the volume of $H_2SO_4$ phase also increased by up to 13.1 vol%. In particular, the effect of ultrasound irradiation on the phase separation was improved with decreasing operating temperature, $I_2$ and $H_2O$ feed concentrations. The ultrasound irradiation induces the formation of additional $H_2O$ molecules by shifting microscopically the reaction equilibrium in the $HI_x$ phase. Afterward, the additionally generated $H_2O$ and isolated $H_2SO_4$ molecules form more $H_2SO_4{\cdot}xH_2O$ (x = 5-6) clusters that can be moved to the $H_2SO_4$ phase.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.4
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• pp.389-397
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• 2019

Lysosomes are cellular organelles involved in energy metabolism and intracellular digestion in eukaryotic cells, including protease, nuclease, glycosidase, lipase, and phosphatase. Our previous studies have confirmed that egg white lysosomes had melanin decolorization and reduction activity. However, there have been few studies on skin barrier and skin regeneration as well as inhibition of melanin production by egg white lysosomes on B16F10 melanocyte cell line. In this study, we attempted to identify the effect of lysosome-related organelle extract (LOE) extracted from egg white on the melanin content change and skin barrier enhancement in cells. First, cytotoxicity evaluation was performed on B16F10 melanocyte cell line to confirm the whitening efficacy of LOE. Cytotoxicity by LOE was not observed at 20 mg/mL concentration, but cytotoxicity was observed at 40 mg/mL, and the maximum concentration value was set to 20 mg/mL in all subsequent experiments. LOE samples of 5, 10, 20 mg/mL inhibited melanin production by 61.5 ± 4.0%, 61.4 ± 7.3%, 58.3 ± 8.3%, respectivly, compared to α-MSH, a negative control in melanin contents assay. MITF mRNA expression was reduced by about 39.7 ± 3.2% compared to the α-MSH treatment group. TEER assay using HaCaT showed that LOE increased TEER resistance in a dose-dependent manner, indicating that LOE is involved in strengthening the skin barrier. LOE also increased the TEER resistance under TNF-α treatment. Skin barrier was normally restored by LOE even under the condition of inflammation. LOE had a positive effect on cell division and cell migration promotion, confirmed by the observing the effect of promoting cell migration by LOE through cell migration assay. Taken together, we expect that LOE can be developed as a cosmetic material to enhance has effects on skin regeneration and skin barrier strengthening as well as whitening function if enzyme stabilization and formulation technology are combined.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.63-74
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• 2006

In order to identify the Pb pollution and its sources in continental shelf and slope areas, Pb concentration and Pb isotope ratios ($^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$) were determined far 6 box corer sediments collected from the southern East/japan Sea. Pb concentration, and $^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$ ratios were constant at around $25\pm5 ppm$ and 0.842 and 2.092 from 1700 to 1930 year, respectively and increased steadily up to $40\pm5 ppm$ and 0.867 and 2.123 at the beginning of 1990s', respectively. The increase of concentration and isotope ratios in the labile fraction (leached by 2M HC1+0.5M $HNO_3$) explains their increase in bulk sediments, while Pb concentration and isotope ratios in the residual fraction were nearly constant during 300yrs. Temporal variation of Pb isotope ratios was explained by simple two end-members mixing of geo-genic and anthropogenic sources because isotope ratios and the inverse of Pb concentration showed the good linear relationships. Using Pb isotope ratios, we can constrain two Pb sources in the study area. The one is atmospheric particulates, compared with mean values of isotope ratios in atmospheric particulates collected at Jeju and Oki ;stands, based on the history of Pb emmission in Korea and China, and judged by oceanographic processes capable of homogenizing many sources. The other is local sources related to iron mills, refineries of Pb ore and of petroleum located at the coast of the study area. Isotope ratios of anthropogenic Pb can be estimated using two end-members mixing equation and were $0.879\pm0.005\;and\;2.144\pm0.008$ before 1950s' while they increased up to $0.900\pm0.008\;and\;2.162\pm0.011$ after 1980s', respectively.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.189-198
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• 2009

This survey was conducted to investigate the situation of housing type in poultry farms in Korea. The number surveyed among the farm size over 30,000 heads was 1,965 farms. Poultry housing types of windowless, open sided, vinyl house type were 19.0, 47.7, 19.8%, respectively. Waterers of nipple, bell, and 8 feet trough used in smaller than 50,000 heads of poultry farm were 40.6, 11.3 and 42.8%, respectively. But the bigger farm in the farm size of over 100,000 heads used more nipple waterer. Feeders of disk, hopper and chain used in poultry farm were 54.5, 16.3, 15.8%, respectively. Manure collecting system of scraper and belt was 29.4, 71.5 %, respectively. Ventilation systems of natural ventilation, natural + mechanical ventilation, mechanical ventilation were 40.5, 39.8, 20.7%, respectively.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.438-457
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• 2019

The main purpose of this paper is to identify the entry types and locational determinants of North Korean workers in cross-border regions between North Korea and China. More specifically, the paper has attempted to divide the entry type of them in the regions into two; 1) entry via transactions between Chinese traders with North Korea and North Korea trade companies, and 2) entry via transactions between Korean-Chinese middlemen and North Korean trade companies. Also, it has analyzed main factors of their locational determinants in the spatial contexts of the regions. There have been changes in two perspectives in terms of the entry paths and types of them in accordance with the transformation of characteristics of United Nations sanction against North Korea from 'call-upon' to 'decide' after UN Security Council Resolution 2094 in 2013. Firstly, main agents who have dealing with North Korean trade companies which have right to dispatch North Korean workers have been changed from Chinese traders into Korean-Chinese brokers who are specialized in the introduction of North Korean workers with one-stop service from visa administrative to labor managements. Secondly, there has been a transfer of North Korean workers in the regions from formal to informal workers who has been admitted into China with a short stay or a tourist visa, and then remained illegally to be employed in China. Therefore, as demands on service which is able to guarantee the security of North Korean informal workers and their managements have increased, Korean-Chinese brokers have been stimulated in the regions after the operation of real international sanctions against overseas North Korean workers. In addition, the main factors of their locational determinants in cross-border regions between North Korea and China are could be analyzed in three perspectives; 1) an increase in real wages in accordance with the reform of the Chinese social insurance system after 2011, 2) the structural vulnerability of labor markets in the regions, 3) the utilization of stable and manageable workers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.454-458
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• 2014

In this study, we examined the ionization rate and permeability of nanocalcium prepared from oyster shells with various particle sizes. Four particle sizes of the calcium samples were prepared by centrifugation according to their density disparity in alcoholic solution: NC (normal calcium), C-1 (supernatant of 1,000 rpm), C-2 (supernatant of 2,000 rpm), and C-3 (supernatant of 3,000 rpm). Particle sizes of NC, C-1, C-2, and C-3 were $2,280.3{\pm}64.3nm$, $521.3{\pm}83.3nm$, $313.9{\pm}29.5nm$, and $280.0{\pm}3.4nm$, respectively. C-3 showed a slight increase in ionization rate compared with the other calcium samples, but their differences were not significant. Dialysis membrane-employed analysis showed that nanocalcium permeability increased as its particle size smaller; 32% of C-3 nanocalcium was transported to the outside of the membrane, whereas C-1 showed a 25% transport rate. We determined the permeability of the nanocalciums by using rat intestinal sacs, in order to provide different intestinal environments depending on pH level. Nanocalcium generally showed a higher permeability at pH 7, which represents an ileum environments compared to the duodenum and jejunum environments at pH 4.2 and pH 6.2, respectively. However, C-3 calcium showed the highest permeability, followed by C-2, C-1 and NS calciums. This result shows that the size of calcium positively affected its permeability in the intestinal sac. Taken together, nano-sized calcium derived from discarded oyster shell shows improved permeability in intestinal environments.

• Journal of Mushroom
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• v.2 no.3
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• pp.149-156
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• 2004

This study was carried out to obtain basic data on physiological characteristics for an artificial cultivation of fruiting body of Cordyceps. Specimens such as Cordyceps longissima, C. militaris and C. pruinosa were collected at Mt. Halla of Cheju island in July, 2003. Among four different culture media which have been used for culture of mushrooms, MCM medium was selected for the favorable culture medium of the Cordyceps tested. The initial pH of solid medium for mycelial growth of Cordyceps was good in the range of pH 5.0~7.0 lower than 8.0. The mycelial growth of C. longissima was most favorable on culture media supplemented with glucose, one of monosaccharides. In C. militaris, nine carbon sources were favorable to the mycelial growth as compared with control among 11 carbon sources. Six nitrogen sources were favorable to the mycelial growth of C. longissima as compared with control among 9 carbon sources; namely, the mycelial growth of C. longissima was most favorable on culture media contained potassium nitrate, and followed in order by ammonium citrate and sodium nitrate in 4 weeks incubation.