• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.249-259
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• 2014

Cryopreserving cells which are maintaining their viability are the very complex process. This study has been carried out in order to find the effects of cryopreservation steps and freezing media on the rates of viability of cryopreserved chicken primordial germ cells (PGCs). PGCs obtained from the germinal gonade of 5.5~6 day (stage 28) chick embryos of Korean Ogye (KO) and Commercial breeds (C), using the MACS method were suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG)). Gonads were harvested from stage 28 chick embryos and pooled in groups of 5, 10, 15, 20E embryos, contributing gonads to the cell suspension. The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments : 2.5%, 5%, 10%, 15% and 0% cryoprotectant (DMSO, EG, PG) as a control. Effects of exposure to slow freezing and vitrification, with different concentrations of the cryoprotectant solution, were examined. After vitrification and slow freezing, survival rates of the frozen-thawed PGCs from the 10% EG plus FBS treatment were 85.63%, and 66.14% (p<0.05), respectively. The viability of PGCs after freeze-thawing was significantly higher for 10% EG plus FBS treatment than for 10% PG + FBS treatment (p<0.05) (85.63% vs 66.81%) by vitrification. This study established a method for preserving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at a germplasm repository and ease of entry into a data base. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.

• Progress in Medical Physics
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• v.21 no.2
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• pp.192-200
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• 2010

Cyberknife with small field size is more difficult and complex for dosimetry compared with conventional radiotherapy due to electronic disequilibrium, steep dose gradients and spectrum change of photons and electrons. The purpose of this study demonstrate the usefulness of Geant4 as verification tool of measurement dose for delivering accurate dose by comparing measurement data using the diode detector with results by Geant4 simulation. The development of Monte Carlo Model for Cyberknife was done through the two-step process. In the first step, the treatment head was simulated and Bremsstrahlung spectrum was calculated. Secondly, percent depth dose (PDD) was calculated for six cones with different size, i.e., 5 mm, 10 mm, 20 mm, 30 mm, 50 mm and 60 mm in the model of water phantom. The relative output factor was calculated about 12 fields from 5 mm to 60 mm and then it compared with measurement data by the diode detector. The beam profiles and depth profiles were calculated about different six cones and about each depth of 1.5 cm, 10 cm and 20 cm, respectively. The results about PDD were shown the error the less than 2% which means acceptable in clinical setting. For comparison of relative output factors, the difference was less than 3% in the cones lager than 7.5 mm. However, there was the difference of 6.91% in the 5 mm cone. Although beam profiles were shown the difference less than 2% in the cones larger than 20 mm, there was the error less than 3.5% in the cones smaller than 20 mm. From results, we could demonstrate the usefulness of Geant4 as dose verification tool.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.422-429
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• 2013

It is generally known that the increase of the Earth surface temperature due to the global warming together with the land desertification by rapid urban development has caused severe climate and weather change. In desert or desertification land, it is observed that there are always severe flooding phenomena, even if desert sand has the high porosity, which could be believed as the favorable condition of rain water infiltration into ground water. The high runoff feature causes possibly another heavy rain by quick evaporation with the depletion of underground water due to the lack of infiltration. The basic physics of desert flooding is reasonably assumed due to the thermal buoyancy of the higher temperature of the soil temperature than that of the rain drop. Considering the importance of this topic associated with water resource management and climate disaster prevention, no systematic investigation has, however, been reported in literature. In this study, therefore, a laboratory scale experiment together with the effort of numerical calculation have been performed to evaluate quantitatively the basic hypothesis of run-off mechanism caused by the increase of soil temperature. To this end, first, of all, a series of experiment has been made repeatedly with the change of soil temperature with well-sorted coarse sand having porosity of 35% and particle diameter, 2.0 mm. In specific, in case 1, the ground surface temperature was kept at $15^{\circ}C$, while in case 2 that was high enough at $70^{\circ}C$. The temperature of $70^{\circ}C$ was tested as this try since the informal measured surface temperature of black sand in California's Coachella Valley up to at 191 deg. $^{\circ}F$ ($88^{\circ}C$). Based on the experimental study, it is observed that the amount of runoff at $70^{\circ}C$ was higher more than 5% compared to that at $15^{\circ}C$. Further, the relative amount of infiltration by the decrease of the surface temperature from 70 to $15^{\circ}C$ is about more than 30%. The result of numerical calculation performed was well agreed with the experimental data, that is, the increase of runoff in calculation as 4.6%. Doing this successfully, a basic but important research could be made in the near future for the more complex and advanced topic for this topic.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.326-333
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• 2009

Heterocyclic aromatic amines (HCAs) are mutagenic and carcinogenic substances that are formed during the heating of protein-rich foods. HCAs are generally found at low amounts in a complex matrix, which requires sophisticated analysis. In this study, HCAs were extracted from lyophilized fish and shellfish samples using solid-phase extraction (SPE) and determined by liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI-MS). The HCA recoveries in the fish and shellfish ranged from 15.7 to 74.7% with standard deviations from 0.2 to 7.63%. And HCA concentrations ranged from 0.8 to 1,117.7 $ng/g^{-1}$ in cooked food samples. 1-methyl-9H-pyrido[3,4-b]indole (Harman), 9H-pyrido[3,4-b]indole (Norharman), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were the most abundant HCAs formed in the muscle of fried mackerel, at levels of 1,117.7, 926.6, and 133.7 ng/g, respectively. 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-aminodipiryrido[1,2-a:3,2-d]imidazole(Glu-P-2), 2-amino-9H-pyrido[2,3-b]indole(A${\alpha}$C), 2-amino-3methyl-9H-pyrido [1,2-a:3,2-d]imidazole(MeA${\alpha}$C), 2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline (TriMeIQx), 2-amino-3,7,8-trimethylimidazo [4,5-f]quinoxaline(7,8-DiMeIQx), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) were only detected by small quantities ranged from 1.5 to 98.6 ng/g. Overall, this study provides useful information on HCA levels in fish and shellfish products consumed in Korea.

• Journal of Life Science
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• v.25 no.1
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• pp.53-61
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• 2015

In this study, we tried to separate the photosensitizer that induces apoptosis of leukemia cells (U937) from perilla leaves. Perilla leaves (Perilla frutescens Britt var. japonica Hara) are a popular vegetable in Korea, being rich in vitamins (A and E), GABA, and minerals. Dried perilla leaves were extracted with methanol to separate the photosensitizer by various chromatographic techniques. The structure of the isolated compound (PL9443) was identified by 1D-NMR, 2D-NMR, and FAB-mass spectroscopy. Absorbance of the UV-Vis spectrum was highest at 410 nm and was confirmed by the 330, 410, and 668 nm. PL9443 compound was determined to be pheophorbide, an ethyl ester having a molecular weight of 620. It was identified as a derivative compound of pheophorbide structure when magnesium comes away from a porphyrin ring. Observation of morphological changes in U937 cells following cell death induced by treated PL9443 compound revealed representative phenomena of apoptosis only in light irradiation conditions (apoptotic body, vesicle formation). Results from examining the cytotoxicity of PL9443 substance against U937 cells showed that inhibition rates of the cell growth were 99.9% with the concentration of 0.32 nM PL9443. Also, the caspase-3/7 activity was 99% against U937 cells with the concentration of 0.08 nM of PL9443 substance. The result of the electrophoresis was that a DNA ladder was formed by the PL9443. The PL9443 compound is a promising lead compound as a photosensitizer for photodynamic therapy of cancer.

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.477-488
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• 2020

Recently, foodborne illness outbreaks linked to fresh produce are being increasingly reported in the United States, the EU, and Korea as well. Some of this increase may be due to improved surveillance, increase in consumption, change in consumers' habits, and complex distribution systems. Garlic chive is a green, fresh-cut vegetable consumed year-round as a nutrition-rich herb in Korea. It is also prone to contamination with foodborne pathogens during pre-harvest, as amendment with high amounts of livestock manure or compost to soil is required in its cultivation. Our aim in this study was to evaluate microbial contamination of garlic chives, garlic chives cultivation soil, compost, and irrigation water in the southern part of Korea. Samples were collected in A, B, and C regions in 2019 and 2020, and 69, 72, 27, and 40 of garlic chives, soil, compost, and irrigated water, respectively, were analyzed for the presence of sanitary indicator bacteria (total aerobic bacteria, coliforms and Escherichia coli), Bacillus cereus, Staphylococcus aureus, pathogenic E. coli, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp. In A, B, and C regions, levels of total aerobic bacteria, coliform, B. cereus, and S. aureus on all samples were between 1.14 and 8.83 log CFU/g, 0.43 and 5.01 log CFU/g, 0.41 and 5.55 log CFU/g, and 1.81 and 6.27 log CFU/g, respectively. B. cereus isolated from garlic chives and environmental samples showed β-hemolysis activity. Incidence of S. aureus in garlic chive and its production environments in 2020 was different from 2019. In this study, B. cereus and S. aureus were the only pathogenic microorganisms detected in all samples. As a result, this work suggests that continuous monitoring in the production and pre-harvest environment is required to improve hthe hygiene and safety of garlic chive.

• Korean Journal of Health Education and Promotion
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• v.1 no.1
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• pp.21-36
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• 1983

It is assumed that menarche is affected not only by the biological factors such as nutrition and genetic heritage, but also it is affected by other socio-cultural environmental factors including weather, geographic location, education and level of modernization. Also recent trend of menarche in Korea indicates that a lot of discussion are being generated to the need of sex education as a part of formal school education. The purpose of this study is to develop the school health education program by determine the age of menarche, the factors relavant to time of menarche and psycho-mental state of students at the time in menarche and investigate the present state of school health education relate to menarche of adolescents. The total number of 732 girls was drown from first, second and third grades of 4 middle schools in Seoul. For the data collection the survey was conducted during the period from May 1 to May 20, 1982 by using prepared questionair. The major results are summarized as follow; 1. Mean age at menarche and the percent distribution of menarche experienced. It was observed that about 68.7% of sampled students have been experienced menarche at the time interviewed. For the each group, age at menarche is revealed that among the students about 37.8% are experienced menarche for under 12 years old group, 62.1% for 13 year-old group, 80.6％ for 14 year-old group and 95.5% for over 15 years old. In sum it was found that the mean age at menarche was 12.3 years old, ranged from age at 10 as earlist the age at 15 as latest. 2. Variables associated with age at menarche. 1) There was tendency those student who belong to upper class economic status have had menarche earlier than those student who belong to lower class. Therefore, economic status is closely related to age at menarche. 2) In time of mother's education level, it is also found that those students whose mother's education levels from high school and college are experienced menarche earlier than those students whose mother's education levels from primary school and no-education. 3) However, in connection with home discipline, there was no significant relationship between age at menarche and home disciplines which are being treated "Rigid", "Moderated ", "Indifferent". 4) Degree of communication between parents and daughter about sex matters was found to be associated each others in determination of age at menarche. 5) It was found that high association between mother's menarche age and their daughter's menarche age was observed. Mother's age at menarche earlier trend to be shown also as earlier of their daughters. 6) Those students belong to "D & E" of physical substantiality index are trend to be earlier in menarche than those students in the index "A & B". 3. Psycho-mental state at the time of menarche. Out of the total students 68.2% had at least one or more than one of subjective symptoms. Shyness was shown as most higher prevalent symptom and others are fear, emotional instability, unpleasant feeling, depression, radical behavior, inferior complex and satisfaction appeared. Very few cases are appeared be guilty and stealing feeling. 4. The present status of school health education program related to menarche. As to the source of information about menarche, teacher was a main source with average index 5.88 and the other informants were mother & family member, friends, books and magagines, movies, television, and radio. For the problem solving at menarche, mother & family members were subject to discussion with an average index 6.02 as high. The others for discuss and knowledge about menarche were books, magagine, friends, teachers, and self-learning based on own experienced. The time of learning about menarche, it was learned as highest percentage with 43.2% at a 6 grades of primary school, middle school with 34.4%, 5 grade of primary school with 18.2%, and 4 grade of primary school with 4.0% respectively.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.705-720
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• 2018

The purpose of this study is to shed light on the meaning and value of interest (in Korean 'Jae-mi') in science education through literature analysis. Literature analyses were conducted on literature related to interest in various fields such as Korean language, psychology, philosophy, and education. Specifically, this study discussed the meaning of interest, the characteristics of the context of experiencing interest, the educational value of interest in science education, and the direction of science education to realize the value of interest. First, it was found that interest is an experience of emotional activation that can be felt through interaction with a specific object, and it is an emotional experience caused by the complex combination of various psychological factors, which is oriented sense, relationship, self, and object. Second, to understand the context of experience of interest, we conducted a topic modeling analysis with 1173 research articles related to interest. As a result of the analysis, it was confirmed that the context of interest is closely related with playfulness. And we addressed that this kind of playfulness is also found in science. Third, the educational values of interest in science education were discussed. In science education, fun is not only an instrumental value to induce science learning behavior, it is also one of the universal experiences that learners feel lively in science teaching-learning, and driving force of individual students' emotional development related to science. The students' active attitude to feel interest lead to creative thinking and action. Finally, we argued that the interest that should be aimed in science education should be active interest and experienced at trial and error, not passive interest induced by external stimuli. And science education culture should be encouraged to respect those who enjoy science. In particular, this study discussed the importance of each student's unique interest experience based on the philosophy of philosopher Deleuze (1976).

• Journal of Life Science
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• v.18 no.1
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• pp.16-22
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• 2008

In this study to evaluate the involvement of EGFR, HER-2/neu and ALCAM (CD166) oncogene products in canine mammary neoplastic lesions, sections of archived paraffin-embedded samples of 49 mammary tumors were analyzed immunohistochemically using antibodies against human EGFR and HER-2/neu and ALCAM. These 49 tumors were divided into 2 groups: 22 benign (19 adenoma, 3 benign mixed tumors) and 27 malignant tumors (2 simple adenocarcinomas, 5 complex adenocarcinomas, 3 solid carcinoma, 5 sclerosing carcinoma, 8 malignant mixed tumors and 4 malignant myoepithelioma). As a result of immunostaining, 31.8% (7/22) of the benign tumors and 29.6% (8/27) of the malignant tumors expressed the HER-2/neu oncogene product, EGFR expression was detected in 27.3% (6/22) of benign tumors and in 22.2% (6/27) of the malignant tumors. ALCAM expression was detected in 40.9% (9/22) of benign tumors and in 7.4% (2/27) of the malignant tumors. These results suggest that some of the biological and morphological characteristics of the tumor are associated with canine mammary gland tumors, as also reported for human breast cancer, the possibility of using anti-HER-2/neu antibodies in the treatment of canine mammary tumors.

• Journal of Conservation Science
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• v.27 no.1
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• pp.101-114
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• 2011

The rock-carved Buddha statue at Dosolam (Korea Treasure No. 1200) of the Seonunsa temple in Gochang is unique style sculptured on natural rock cliff of 13.0m height. The Buddha statue is composed of volcanic complex with tuff, dacitic tuff breccia, tuff bereccia and lithic tuff. Especially, the Buddha statue is characterized by hydrothermal alteration and fragmentation on the upper and lower part. As a result of damage diagnosis, exfoliation and detachment of physical weathering are high of 11.3% and 9.3%, respectively. Infrared thermography analysis, exfoliation and micro-cracks occurred in the measuring parts that have not been confirmed by naked eyes. Chemical index of alteration and weathering potential index of host rock for the Buddha statue are 55.16 to 64.01 and 6.14 to 9.92 which are represented within highly weathering degree. In surface, dark black, reddish brown and white discoloration are observed prominently in the lower. Brown discoloration 6.9% is highest. According to the P-XRF measurements, high concentration of Fe in common, in part of dark black discoloration was Mn, white and brown discoloration in part of S and Ca content were higher. Biological weathering that yellowish brown and dark gray crustoes lichenes appeared by 20.8% and 13.3%, respectively. Therefore, comprehensive deterioration rate of Buddha statue show physical damage by 21.2%, discoloration for inorganic contaminants by 10.8% and biological damage by 39.4%. Ultrasonic velocity measurement carried out of Buddha statue on the surface by 555 points. Measured value of ultrasonic velocity was about 2,273m/s(1,067 to 3,215m/s, and weathering coefficient is 0.5(0.4 to 0.8) that progress on MW(moderately weathered) to HW(highly weathered) grade of rocks.