• Journal of Biomedical Engineering Research
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• v.29 no.4
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• pp.316-322
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• 2008

The purpose of this study was to investigate muscle activation of lower extremity such as rectus femoris, tibialis anterior and soleus according to 0cm(bare foot), 4cm and 7cm heel height of shoe on the rocking surface in older women. 20 older women who did not have any lower musculoskeletal and neurological disorders in the past were participated in this study. Each subject was standing for 15 seconds on the level 8 of Biodex Stability System (BSS) while wearing 4cm and 7cm heel height shoes including bare foot. Electromyography was used to measure muscle activation of lower extremity, and the muscle activation was expressed as a percentage of maximal voluntary isometric contraction (% MVIC). We measured % MVIC of three muscles during 5 seconds except for the first 5 seconds and last 5 seconds. SPSS 12.0 program was used for this study. Repeated one-way analysis of variance(ANOVA) was performed to compare the significant difference among the muscles of lower extremities according to heel heights of shoe on the rocking plate. % MVIC of each muscle such as rectus femoris, tibialis anterior and soleus regarding heel heights of shoe had statistically significant differences (p<0.05). The results of contrast test were as follows; 1) % MVIC of rectus femoris had significant differences between barefoot and 4cm, and barefoot and 7cm. 2) % MVIC of tibialis anterior had significant differences between barefoot and 4cm, barefoot and 7cm, and 4cm and 7cm. 3) % MVIC of soleus had significant differences between barefoot and 7cm, 4cm and 7cm. The results indicate that all commonly responsive muscle on the conditions of barefoot, 4cm, and 7cm shoe height on the rcoking surface is tibialis anterior muscle. We found out that the more heels of shoe high, the more muscle activation increases. High-heeled shoes above 7cm remarkably increase the muscle activation of lower extremity and may result in muscle fatigue. Thus, these shoes may summate risk factors of falls in older women. We can acknowledge that the heels above 4 cm affect each muscle activation in lower extremity on the rocking surface.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.611-619
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• 2017

Objective : In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis. Methods : A validated 3-dimensional, nonlinear ligamentous cervical segment (C3-7) finite element model was used. This study simulated a single-level ACDF at C5-6 with a cylindroid interbody graft. The variables were the properties of the incorporated interbody graft (cancellous bone [Young's modulus of 100 or 300 MPa] to cortical bone [10000 MPa]) and the contact area between the vertebra and interbody graft (Graft-area, from 10 to $200mm^2$). Interspinous motion between the flexion and extension models of less than 2 mm was considered solid fusion. Results : The minimal Graft-areas for solid fusion were $190mm^2$, $140mm^2$, and $100mm^2$ with graft properties of 100, 300, and 10000 MPa, respectively. The minimal Graft-areas were generally unobtainable with only the formation of InGBB after the use of a commercial stand-alone cage. Conclusion : ExGBB may be formed to compensate for insufficient InGBB. Although various factors may be involved, solid fusion with less formation of ExGBB may be achieved with refinements in biomaterials, such as the use of osteoinductive cage materials; changes in cage design, such as increasing the area of polyetheretherketone or the inside cage area for bone grafts; or surgical techniques, such as the use of plate/screw systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.120-127
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• 2016

This study examined the dynamic characteristics of the gate to identify the optimal gate installation direction according to the installation direction. A 1:31 scale model was constructed for a 47.5m prototype gate using acrylic. The scaled weights were tuned by adding lead weights. The first step was to measure the natural frequencies of the model gates, and compare them with finite-element analysis of the prototypes as a calibration. The scaled model was tested in a 1.6 m wide concrete flume for two orientations to determine the effects of the gate orientation on structural vibrations. Vertical vibrations were measured under a range of operational conditions, including a range of bottom opening heights and different upstream and downstream water levels. For large bottom opening heights in the normal direction, relatively large vibrations were induced by vortices shed at the plate bottom that would strike the horizontal truss member. This phenomenon was avoided in the reverse direction. For small bottom opening heights in the normal direction, these vibrations were caused by a suction force that developed at the gate bottom. The gate model in the reverse direction was preferred because of its low overall vibrational response under general gate opening and flow level combinations.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.356-363
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• 2010

For this paper, we investigated the area specific resistance (ASR) of commercially available ferritic stainless steels with different chemical compositions for use as solid oxide fuel cells (SOFC) interconnect. After 430h of oxidation, the STS446M alloy demonstrated excellent oxidation resistance and low ASR, of approximately 40 $m{\Omega}cm^2$, of the thermally grown oxide scale, compared to those of other stainless steels. The reason for the low ASR is that the contact resistance between the Pt paste and the oxide scale is reduced due to the plate-like shape of the $Cr_2O_3$(s). However, the acceptable ASR level is considered to be below 100 $m{\Omega}cm^2$ after 40,000 h of use. To further improve the electrical conductivity of the thermally grown oxide on stainless steels, the Co layer was deposited on the stainless steel by means of an electroless deposition method; it was then thermally oxidized to obtain the $Co_3O_4$ layer, which is a highly conductive layer. With the increase of the Co coating thickness, the ASR value decreased. For Co deposited STS444 with 2 ${\mu}m$hickness, the measured ASR at $800^{\circ}$ after 300 h oxidation is around 10 $m{\Omega}cm^2$, which is lower than that of the STS446M, which alloy has a lower ASR value than that of the non-coated STS. The reason for this improved high temperature conductivity seems to be that the Mn is efficiently diffused into the coating layer, which diffusion formed the highly conductive (Mn,Co)$_3O_4$ spinel phases and the thickness of the $Cr_2O_3$(S), which is the rate controlling layer of the electrical conductivity in the SOFC environment and is very thin

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.29-40
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• 2008

Police agency is indicated that the number of children's traffic accident is tending downwards, however about one child is dead every day due to traffic accident. Major parts of the accidents happen during walking; among the rest, jaywalking is the biggest reason. Many accidents take plate on the road to school or near the home so government legislate children safeguard zone at 1995. According to the legislation, drivers have to reduce speed and there are safety facilities for children at children safeguard zone. This study finds the problems of children safeguard zone and suggest more effective and quantitative method for children safeguard zone. Firstly this study grasps the characters of children's pattern movement and children's traffic accident at children safeguard zone and then divides specific danger factors of children's traffic accident at children safeguard zone. Secondly, each factor is given danger level depending on danger degree and suggests effective method for assignment standard of children safeguard zone using all of these things.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.329-335
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• 2003

This study was carried out to investigate physiological activities of chicory root (Cichorium intybus L. var. sativus). The anti-hepatotoxic activity of roasted chicory was studied using primary cultured rat hepatocytes where cytotoxicity was induced by galactosamine. The water extract of roasted chicory did not induced of cytotoxicity in primary cultured rat hepatocytes. Treatment with 5 mM galactosamin for 5.0 hr showed maximum increase in activity of lactic dehydrogenase (LDH) released in the medium. The water extract of roasted chicory inhibited significantly and dose-dependently the release of LDH activity increased by galactosamine-induced cytotoxity. The antidiabetic activity of water extract of roasted chicory was examined in streptozotocin induced diabetic rats. The increased blood glucose level in the streptozotocin induced diabetic rats was significantly decreased by the administration of chicory extract (800 mg/kg). Chicory water extract (800 mg/kg) prevented weight losses in streptozotocin induced diabetic rats. The antimutagenic activities of chicory water extract were tested using Salmonella thyphimurium YG 1024 as tester strains and 2-aminofluorence as a potent carcinogen in the presence of S-9 mix. No mutagenic activities of the water extracts of roasted chicory were observed on all the tested strains at dose $10{\sim}5,000$ ${\mu}/g$ per plate. Water extract of roasted chicory did not inhibit the mutagencities of Salmonella thyphimurium YG 1024 induced by 2-aminofluorene.

• KSBB Journal
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• v.11 no.4
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• pp.445-452
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• 1996

To investigate the promoter effect on heterologous gene expression in S. cerevisiae, the recombinant plasmids pYI11, pYI12, pYI10-2, and pYIGP were constructed to contain the inulinase gene (INUI) as a reporter under the control of GAL10, GAL7, GAL1, and GAP promoters, respectively. When the yeasts transformants were cultivated on galactose-containing rich media, the cell growth reached to 36-39 OD600 at 72 hours of cultivation. The specific growth rates of the cells harboring the four different plasmids decreased similarly : they dropped from $0.24 h^{-1}$ during the glucose-consuming period to 0.04 -$0.10 h^{-1}$ during the galactose-consuming period (gene expression phase for GAL promoter system). After the depletion of glucose, the expression of inulinase gene was started and reached to maximal levels of 4.3(GAL1 promoter), 4.0(GAL10 promoter), 3.8(GAL7 promoter), and 1.6(GAP promoter) unit/mL at 72 hours of cultivation. Based on the maximal expression level and activity staining on the plate, the promoter strength was in the order of GAL1, GAL10, GAL7 and GAP promoter. While the GAL-promoter systems showed a high plasmid stabilities of more than 78%, the GAP-promoter plasmid revealed a lower plasmid stability of 55%. Most of inulinase activity (98%) was found in the extracellular medium, indicating that the secretion efficiency of inulinase is independent on the type of promoter.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.221-228
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• 2004

In recent years building floors become larger and more spacious due to the development of new design methods and high strength and light weight materials. However, such long span floor systems may provide smaller amount of damping and have a longer period so that they may be more vulnerable to the floor vertical vibration. In Korea when floors are to be checked against the floor vertical vibration, the provisions developed in foreign countries have been used. However these guidelines have been developed based on human perception, which may vary from country to country. Also, Korea have particular floor systems, such as flat plate floor system of apartment building. This study attempts to evaluate the vibration performance of the floors in typical apartment buildings. Two different floors with the area of $28 m^2$ and $32 m^2$ were investigated. The criteria provided by ATC-1(1999), AISC-11(1997), AIJ(1991) and the local criteria developed in the previous study(Han, 2003) was used to check the acceptability of the floor vertical vibration.

• Journal of The Korean Association For Science Education
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• v.38 no.4
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• pp.519-526
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• 2018

The purpose of this study is to analyze the Korean high-school physics teachers' difficulties in teaching textbook physics inquiries. For this purpose, 63 high school physics teachers completed a questionnaire. We asked teachers to evaluate the degree of difficulty in teaching textbook physics inquiries. Additionally, we asked physics teachers to select the two most difficult inquiries to teach and to express their reasons for these selections. The main results are as follows: First, the degree of difficulty for all the inquiry is 2.79, indicating a little easy level of difficulty. The two most difficult inquiries are 'Meissner effect experiment' and 'Investigation of diode characteristics using $Cu_2O$ plate and ZnO powder.' Second, the difficulty reasons to teach physics inquiry was presented in the order of 'environment domain,' 'textbook domain,' 'student domain,' and 'teacher domain.' In particular, the biggest reasons for difficulty for teachers are 'preparation of experimental apparatus' and 'safety.' There are many opinions related to 'problem of the experiment itself' in 'textbook domain' and 'lack of ability to manipulate' in 'student domain.' Based on the results of this study, we added a discussion to activate the high school physics textbook inquiries.

• Culinary science and hospitality research
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• v.20 no.6
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• pp.200-210
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• 2014

The purpose of this study was to investigate the quality changes and contamination of microorganisms such as Escherichia coli, mold and yeast in cherry tomatoes during storage at different temperatures, gas composition and periods(7 and 14 days). This study determined pH, color change and the growth pattern of microorganisms in cherry tomato during storage at $5^{\circ}C$, $10^{\circ}C$ and $15^{\circ}C$. According to the results, pH level was a little raised with storage period. On average, $L^*$, $a^*$ and $b^*$ value of cherry tomato were irregular value of increase and decrease of all gas packaging with storage period. In regard of the types of microorganism, aerobic count plate, coliform count, mold and yeast were detected when cherry tomatoes were stored at $5^{\circ}C$, $10^{\circ}C$ and $15^{\circ}C$ during storage for 14 days. Equally, all microorganisms of cherry tomato were irregular with storage period and complex gas packaging. However, this study determined that packaging with a higher $CO_2$ concentration than $O_2$ concentration can reduce growth of microorganism. These studies can be used as primary data for determining the optimal complex gas to storage enlargement.