• Korean Journal of Childcare and Education
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• v.8 no.1
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• pp.5-24
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• 2012

The purpose of this study was to investigate the cognition on community childcare policy and childcare service needs between working mothers and non-working mothers using the 2008 Child Panel by Korea Childcare Policy Institute. The participants were 654 working mothers and 1,416 non-working mothers. The data were analyzed by $x^2$. The results were as follows; 1) 50% of working mothers and non-working mothers thought that the number of childcare centers was enough. Forty-five percent of working mothers and non-working mothers recognized that the number of kinder gartens and private education institutes was enough. Fifty-two percent of working mothers and 4 5% of non-working mothers thought that use of public leisure facilities were convenient. Twenty-seven percent of working mothers and 20% of non-working mothers thought that use of culture institutes were easily accessible. About 50% of working mothers and non-working mothers felt safe about public security and community safety. 2) Second, working mothers perceived social support higher than non-working mothers in several areas.

• School Mathematics
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• v.18 no.4
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• pp.793-818
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• 2016

The purpose of this study is to explore in detail $5^{th}$ grade students' understanding on the big ideas related to addition of fraction with different denominators: fixed whole unit, necessity of common measure, and recursive partitioning connected to algorithms. We conducted teaching experiments on 15 fifth grade students who had learned about addition of fractions with different denominators using the current textbook. Most students approached to the big ideas related to addition of fractions in a procedural way. However, some students were able to conceptually understand the interpretations and algorithms of fraction addition by quantitatively thinking about the context and focusing on the structures of units. Building on these results, this study is expected to suggest specific implications on instruction methods for addition of fractions with different denominators.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.847-853
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• 2011

Filiform hairs that respond to movements of the surrounding medium are the mechanoreceptors commonly found in arthropods and vertebrates. The hairs function as a sensory system for perceiving information produced by prey, predators, or conspecifics. A mathematical model is proposed, and the parametric analyses for the response of artificial filiform hair are conducted to design and predict the performance of a microfabricated device. The results for the Cytop hair, one of the most popular polymer optical fibers (POFs), show that the fundamental mode has a dominant effect on the hair behavior in an oscillating medium flow. The dynamic behavior of sensory hair is also dependent on the physical dimensions such as length and diameter. It is found that the artificial hair with a high elastic modulus does not show a resonance in the biologically important frequency range.

• Journal of the Mineralogical Society of Korea
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• v.18 no.1
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• pp.53-59
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• 2005

Rb-Sr isotopic ages of oxidized biotite in the weathering profile of granodiorite, Yecheon area, were measured by thermal ionization mass spectrometry, and compared with their K-Ar ages. A decrease of Rb-Sr isotopic age is well correlated with iron oxidation, and consistent with K-Ar age. Octahedral and interlayer cations including Rb and Sr were partly released from the oxidizing biotite by excess positive charge from iron oxidation. Divalent /sup 87/Sr decayed from monovalent /sup 87/Rb was more easily released from biotite, resulting in the reduction of Rb-Sr isotopic age. Weathered biotite is not suitable for the age dating of parent rocks, but behaviour of radiogenic isotopes provides useful information on the geochemical and structural changes of biotite during weathering.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.421-428
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• 1999

Potassium (K) released from weathering of biotite in soils has been recognized as one of major K-sources for plant growth. Sand size biotite in a soil-saprolite-parent rock profile developed under temperate climate was studied in terms of morphological, mineralogical, and chemical changes according to depth employing petrographic and electron microscopes. X-ray diffraction, and electron microprobe. Biotite showed discoloring from black to goldish white and loss paleochroism with decreasing depth. Both edge and layer weatherings of biotite showed in this study. Hexagonal holes and cracks on (001) plane of weathered biotite grains were observed and their members increased with increasing weathering degree. Biotite was altered to kaolinite with or without intermidiate products such as hydrobiotite, degraded biotite, and illite. Average chemical composition of weathered biotite changed to that of katolinite with decreasing depth: increasing concentrations of silicon (Si) and aluminum (Al) and decreasing concentrations of potassium (K), iron (Fe), magnesium (Mg), manganese (Mn), and taitanium (Ti).

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.185-194
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• 2019

The purpose of this study was to investigate the effects of social support, parenting stress, and subjective hapiness on the depression of working mothers who are raising their children and to investigate alternatives to reduce their depression, and provide a practical program based on the study. In this study, we used hierarchical regression analysis to examine the variables that affect the depression of the working mothers. The results of this study showed that in the first stage, support of family, which is a sub factor of social support has a negative effect on depression. In the second stage, parenting stress had a significant effect on the depression of the working mothers. In the third stage, subjective hapiness has a negative effect on the depression of the working mothers. The relationship between variables such as social support, parenting stress, and subjective hapiness of these mothers were revealed, and the implications of lowering the depression of mothers were discussed based on the result of this study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.163-169
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• 1996

인위돌연변이 유기에 의해 벼로부터 새로운 유전형질체를 개발하기 위하여 낙동벼(모품종)에서 고정된 엽록소 결핍계통(ch mutant)을 선발하였다. 이 계통은 생육 초기부터 엽록소결핍으로 정상엽에 비하여 노란색을 나타내기 때문에 엽록소의 광합성 관여 유전자탐색에 이용가능하다. ch mutant는 전 생육기간 동안 모품종의 51~87% 정도의 엽록소 함량을 보였으나 엽록소 a/b 함량비는 차이가 없었다. ch mutant의 총 엽록소 함량은 모품종의 70.2%였으면 anthocyanin 함량과 flavonol 함량은 각각 285%와 142% 로 높은 함량비를 나타냈다. ch mutant의 카로티노이드 함량은 모품종의 71.1%였고, 크산토필 함량은 56.6%였다. 특히 카로티노이드 성분중 lutein과 neoaxanthin 함량은 각각 모품종의 32%와 34.4%로 매우 낮았으며, $\beta$-카로틴은 차이가 없으나 antheraxsnthin 함량은 106.9%오히려 증가하였다. 개엽상태에서나 군락 상태에서 ch mutant의 반사율과 투과율은 모두 모품종에 비하여 높아 광흡수량은 저하되었다. ch mutant는 모품종에 비하여 출수기가 5일 늦고 간자, 수장, 주당수수, 수당 입수, 임실율, 천립 중 수량에 감소하였다. ch mu-tant와 모푸종은 esterase, phosphogluose isomerase, malic enzyme, hexokinase 동위 효소의 밴드 패턴에서 유의할 만한 차이를 나타내지 않았으나 엽록체 단백질의 경우 주요 밴드인 60KD의 분자량에서 차이를 보였다.

• Applied Microscopy
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• v.39 no.2
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• pp.117-124
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• 2009

Clonorchis sinensis is the most important widely distributed parasite of the human bile duct in East Asia and the most prevalent parasitic helminth in Korea. The prevalence rate of human clonorchiasis has remained at about 2.9% in Korea. C. sinensis induces dilatation of the duct, hyperplasia of the mucosa, metaplasia or neoplasia of the mucosal epithelium, periductal inflammation and fibrosis, and thickening of the ductal wall. Fibroblast are the most common cells in connective tissue and are responsible for the synthesis of extracellular matrix components. The fibrosis associated with chronic inflammation and injury may also contribute to cholangiocarcinoma pathogenesis, particularly through an increase in extracellular matrix components, which participate in the regulation of bile duct differentiation during development. In this study, ultrastructural changes, the distribution of lectin receptors and actin protein in cultured SD rat bile duct fibroblast after infection of C. sinensis were observed. Experimental group had been divided into four groups: normal bile duct fibroblast cultured in basal media (G1); C. sinensis infected bile duct fibroblast cultured in basal media (G2); normal bile duct fibroblast cultured in basal media containing excretory-secretory product (ESP) (G1-1); C. sinensis infected bile duct fibroblast cultured in basal media containing ESP (G2-1). Overall, once a host is infected by C. sinensis, it affects the host to the extent that sialic acid of ductal fibroblast is increased. Number of cytoplasmic process of SD rat bile duct fibroblast was increased. Actin protein and sialic acid were located in cell surface. Fibroblast induced by C. sinensis was not recovered to normal fibroblast. The cytoplasm bulk and cytoplasmic process were increased whereas the growth rate of the fibroblast of infected SD rat was reduced rather than that of normal fibroblast. In result, it inhibits fibroblast proliferation and increases actin protein on fibroblast cytoplasm, and so causes fibroblast metamorphosis and cellular mutation.

• Applied Microscopy
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• v.39 no.1
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• pp.57-64
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• 2009

The trapping leaves of Drosera capture insects by secreting sticky mucilage from numerous glandular trichomes (GTs) that are developed on the leaf epidermis. The present study examines and compares the structural features of those trichomes in Drosera binata and D. pygmy with the use of light and electron microscopy. The study focuses primarily on the development and differentiation pattern of the GTs during growth. Upon examination, the upper and lower epidermis were readily distinguishable by the features of GTs in developing leaves. In particular, the GTs were dense in the upper epidermis and along the leaf margin. In D. binata, the capitate GTs with elongated stalk and sessile peltate GTs were found most commonly, whereas only capitate GTs with varying degrees of the stalk length were observed in D. pygmy. Up to ca. $2.2{\sim}3.4\;mm$ long capitate GTs were seen in the leaf margins of D. binata and ca. $3.7{\sim}4.2\;mm$ long GTs having racket-like head with adaxial hemispheric structures, otherwise known as tentacles, were noted in the leaf margin of D. pygmy. The peltate GTs were found to be distributed in the lower epidermis of D. binata. In both species, head cells were dense with cytoplasm containing high numbers of Golgi bodies, ER, mitochondria and small vesicles. Secretory materials accumulated within numerous small vacuoles, then fused together to form a single large vacuole, which serves as a secretory cavity. Flection movement of the marginal GTs and leaf blade GTs, and increased mucilage secretion from the head cells upon contact with prey during the capturing process are considered to be major factors in their active insectivorous mechanism. The findings of this study will be useful in comparisons to similar findings in other species that form adhesive trapping leaves, such as Drosophyllum or Pinguicula., further contributing a better understanding of the function and structure of the trapping leaves of carnivorous plants.

• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.423-430
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• 2005

Ameloblasts are responsible for the formation and maintenance of enamel which is an epithelially derived protective covering for teeth. Ameloblast differentiation is controlled by sequential epithelial-mesenchymal interactions. However, little is known about the differentiation and maturation mechanisms. OD314 was firstly identified from odontoblasts by subtraction between odontoblast/pulp cells and osteoblast/dental papilla cells, even though OD314 protein was also expressed in ameloblast during tooth formation. In this study, to better understand the biological function of OD314 during amelogenesis, we examined expression of the OD314 mRNA and protein in various stages of ameloblast differentiation using in-situ hybridization and immunohistochemistry. The results were as follows : 1. The ameloblast showed 4 main morphological and functional stages referred to as the presecretory, secretory, smooth-ended, and ruffle-ended. 2. OD314 mRNA was expressed in secretory ameloblast and increased according to the maturation of the cells. 3. OD314 protein was not expressed in presecretory ameloblast but expressed in secretory ameloblast and maturative ameloblast. OD314 protein was distributed in entire cytoplasm of secretory ameloblast. However, OD314 was localized at the proxiamal and distal portion of the cytoplasm of smooth-ended and ruffle-ended ameloblast. These results suggest that OD314 may play important roles in the ameloblast differentiation and maturation.