• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.401-409
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• 2021

This study aimed to estimate the photosynthetic capacity of tomato plants grown in a semi-closed greenhouse using temperature response models of plant photosynthesis by calculating the ribulose 1,5-bisphosphate carboxylase/oxygenase maximum carboxylation rate (V_cmax), maximum electron transport rate (J_max), thermal breakdown (high-temperature inhibition), and leaf respiration to predict the optimal conditions of the CO₂-controlled greenhouse, for maximizing the photosynthetic rate. Gas exchange measurements for the A-C_i curve response to CO₂ level with different light intensities {PAR (Photosynthetically Active Radiation) 200µmol·m^-2·s^-1 to 1500µmol·m^-2·s^-1} and leaf temperatures (20℃ to 35℃) were conducted with a portable infrared gas analyzer system. Arrhenius function, net CO₂ assimilation (A_n), thermal breakdown, and daylight leaf respiration (R_d) were also calculated using the modeling equation. Estimated J_max, A_n, Arrhenius function value, and thermal breakdown decreased in response to increased leaf temperature (> 30℃), and the optimum leaf temperature for the estimated J_max was 30℃. The CO₂ saturation point of the fifth leaf from the apical region was reached at 600ppm for 200 and 400µmol·m^-2·s^-1 of PAR, at 800ppm for 600 and 800µmol·m^-2·s^-1 of PAR, at 1000ppm for 1000µmol of PAR, and at 1500ppm for 1200 and 1500µmol·m^-2·s^-1 of PAR levels. The results suggest that the optimal conditions of CO₂ concentration can be determined, using the photosynthetic model equation, to improve the photosynthetic rates of fruit vegetables grown in greenhouses.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.353-359
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• 2012

The identification of effective root zone would clarify dynamics of plant available water and soil water balance. Using the relationship between soil properties and electrical resistivity (ER) the purpose of this research is to identify soil zone affected by a plant root activity using electrical resistivity tomography (ERT) technique. Four plastic containers were prepared for two different soil textures (clay and sandy loam) and one container for each texture was selected for planting four corn seedlings (Zea mays L.) and the others were prepared for the blank. For ERT monitoring, we prepared 0.8 m plastic sticks with 17 electrodes installed with 5 cm space. The Ministing (AGI Inc., Texas) instrument for electrical resistivity measurement and semi-auto converter of electrode arrangement were set up for dipole-dipole array. During 2 months of the corns growing, ERT monitoring was made 3 to 4 days after the irrigation practice. Despite of the same amount water supplied into soils, two textures showed very different apparent resistivity values due to different clay content. The apparent electrical resistivity is consistently lower in clay loam comparing to sandy loam soil implying that plant root does not significantly alter the overall trend of resistivity. When plant root system, however, is active both soils with plants showed 2-7 times higher electrical resistivity and higher coefficient variation than soils without plant, implying the effect of root system on the resistivity, in which may caused by. This result suggests plant root activities regulating the soil water dynamics mainly control the variation of electrical resistivity over soil textural difference. Therefore the identification of water uptake zone would highly be correlated to plant root activities, thus ERT will be feasible approach to identify spatial characteristics of a plant root activity.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.33-41
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• 2020

The landing gear of an aircraft is a device that absorbs and dissipates shock energy transmitted from the ground to the fuselage. Among the landing gears, the semi-active MR damper landing gear is supposed to show high-shock absorption efficiency under various landing conditions and secure the stability when out of control. In the case of the MR damper landing gear using an annular channel rather than orifice, Amesim, a commercial multi-physics program, is considered as more useful than the conventional two-degree-of-freedom model because the damping force generated by the pressure drop through the flow annular path can cause cavitation in the low-pressure chamber of the MR damper with a specific internal structure. In this paper, the main dynamic characteristics of the MR damper landing gear with an annular type flow path structure has been analyzed under the condition of cavitation. Based on the analysis results using Amesim, a design guideline for the MR damper flow path that prevents cavitation has been proposed based on the modification of the arrangement of internal components of the damper. The guideline was verified through a drop simulation.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.429-467
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• 2019

Various digital literacy and critical competencies are crucial for success in the information and media-rich 21st century game of life. This study explores and describes the digital literacy practices of role-players in WildStar, a science fantasy Massively Multiplayer Online Role Playing Game (MMORPG). Active role-players create and participate in group-driven interactive stories while in-character. A hybrid ethnographic method integrating overt participant observation and engagement, collection of community artifacts across multiple sites (such as wikis, discussion boards, and social media), and semi-structured interviews was employed to understand how role-players seek, use, evaluate, and manage information, media, and technology. Role-players used various media and technologies to supplement, simplify, and make role-playing more immersive. The relative digital literacy skill levels of individuals varied, leading role-players to leverage the skills of more proficient or experienced community members. Given the broad appeal of online games and educational benefits of role-playing, implications and applications for digital literacy skills instruction and library programming are also discussed.

• Journal of Life Science
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• v.27 no.8
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• pp.888-895
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• 2017

Salsola collina (S. collina) is an annual plant widely distributed in drought and semi-drought areas, which has been used for a long time as a kind of folk remedy in traditional Chinese medicine for the treatment of hypertension. Previously, the anti-oxidative and anti-cancer activities of S. collina were elucidated in our research group. In this study, the anti-obesity activities of S. collina ethanol extract (SCEE) were evaluated using a pancreatic lipase enzyme inhibition assay and cell culture model. The results showed that SCEE effectively suppressed pancreatic lipase enzyme activity in a dose-dependent manner. Furthermore, SCEE significantly suppressed adipocyte differentiation, lipid accumulation, and triglyceride (TG) content, and triggered lipolysis on insulin, dexamethasone, and 3-isobutyl-l-methylxanthine-treated 3T3-L1 preadipocytes in a dose-dependent manner without cytotoxicity. Its anti-obesity effect was modulated by cytidine-cytidine-adenosine-adenosine-thymidine (CCAAT)/enhancer binding proteins ${\alpha}$ ($C/EBP{\alpha}$), $C/EBP{\beta}$, and the peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$) gene, as well as protein expressions. Taken together, these results offer the important new insight that S. collina possesses anti-obesity properties, such as pancreatic lipase inhibition and anti-adipogenic and lipolysis effects through the modulation of their upstream signaling pathway. It could become a promising source in the field of nutraceuticals, and the identification of active compounds that confer the biological activities of SCEE may be needed.

• Journal of Bio-Environment Control
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• v.8 no.3
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• pp.192-201
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• 1999

This study was aimed to introduce the measurement of $CO_2$ concentration and leaf area index in the phytotron for predicting the effect of CO.E, light and leaf area index on the instantaneous photosynthetic rate of sweet pepper with the existing ASKAM model. Measurements were made in 2 semi-closed phytotron compartments in which three different $CO_2$ concentrations were applied at random. Plants were grown on containers with circulating nutrient solution at 21$^{\circ}C$ and 80-95% relative humidity. The model estimates crop net $CO_2$ uptake for short time intervals during the day based on short-term data of daily radiation, temperature and $CO_2$ concentration. During the photosynthesis measurements, $CO_2$ concentrations in both compartments and in the basement were measured every minute. This was also done for the flow of pure $CO_2$ into the compartment, global radiation, photosynthetic active radiation inside the compartment, temperature and relative humidity. Crop growth models summarize our knowledge on crop behavior and have as such a wide range of applications in analysis, crop management and thus as a farm management tool.

• Journal of Gifted/Talented Education
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• v.25 no.2
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• pp.217-236
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• 2015

The purpose of this study was to investigate factors that affected achievement of socially succeeded people, and to draw ways to improve gifted education. To do this, we interviewed 60 achievers. The interview was administrated as semi-structured deep interview about 6 areas - education, major, family and parent, personal relationship, leisure time activity, achievement and motivation of success. The results showed that achievers were active students during their school days. They thought differentiated education and student-centered lessons are important. Many achievers answered they do not have any personal mentee, and decision of majors and education should be matched with the perception of one's potential and interest. Exercises, music, and reading books were strongly suggested as leisure time activities, and the key inner factors for success were curiosity and self-confidence. Beneficiaries of gifted education perceived their experience of gifted education had a positive influence on their achievement. Based on the these results, ways to improve gifted education were discussed.

• Women's Health Nursing
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• v.1 no.2
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• pp.222-243
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• 1995

The purpose of this study was to develop concrete and in-depth knowledge about menarche and to raise the need of menstrual education. The data were collected from purposively sample 34 women from twenties to forties from April 27 to October 10, 1994. Semi-structured intensive interviews were done and these qualitative data were analysed with "Ethnograph" computer program. The results of the study were as follows : 1. The experience of menarche could be classified into two main groups, which were positive and negative response to menarche. The negative experiences were to be shameful, tearful, scared of the phenomena and thought as a kind of punishment for guilt or confused menarche with other symptoms of diseases. On the contrary, the positive experiences were to be proud of physical maturity and to think that is was wonderful, miraculous and to perceive it as a warm experience. 2. The experience of menarche was influenced by various factors. They were the knowledge about menstruation, the quality and amount of informations, the time of menarche, the environmental factors, the response of significant others toward menarche. The experience of menarche could be positive or negative according to these factors. 3. The previous information sources about menstruation could be significant others, school education and mass-media. The significant others were mothers, sisters, friends and the person in charge of school sex education such as school nurses, home economics, military drill and athletics of teachers. And mass-media included sex education booklets, nursery tales, TV programs, and publicity activities of sanitary napkin companies. 4. The opinions of the subjects about the proper time of menarcheal education could be grossly classified into two groups. The first was active approach toward children when they were in elementary school. The second was passive approach which postponed the time until the child ask about it, because it would be awkward for them to discuss about the topic. 5. The participants thought that the ideal methods of menarche education would be systematic school education programs, open discussion with daughters, audio-visual teachings, or practical education in everyday life. 6. The contents of the menarche education based on the participants' opinions, would be positive details about meanings and functions of menstruation. And it would be desirable if the attitudes of the person in charge of education could be positive, open-hearted, and favorable toward menstruation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.474-481
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• 2004

Squamous cell carcinoma is the most prevalent oral cancer, which is characterized by its low survival rate, high malignancy, mortality with facial defects, and poor prognosis. Exact cause and pathogenesis of the squamous cell carcinoma is still unknown. Various routes including smoking, radiation, and viral infections predispose its genesis, and recent studies revealed that genetic defects which fail to prevent cancer proliferation play a role. Generally, a cancer develops from the decreased rate of apoptosis which is an active and voluntary cell death, and from the altered cell cycles. Anticancer effect can be obtained by recovering the apoptotic process, and by suppressing the cell cycles. Among the apoptosis related factors, bcl-2, caspase-9, and VDAC (voltage-dependent anion channel)are produced in mitochondria of the cell. Cyclosporin-A is known to induce apoptosis through its activation with VDAC. This study was to reveal the anticancer effect of Cyclosporin A to the oral squamous cell carcinoma. The inverted microscope was used to find alterations in the tissue, and sensitivity test to the anticancer cells was performed with MTT (Tetrazolium-based colorimetric) assay. Following cell line culture of primary and metastastic oral squamous cell carcinoma, electrophoresis was performed with extracted total RNA. Finally, semi-quantitative study was carried out through RT-PCR (Reverse Transcription-Polymerase Chain Reaction). The results of this study are as follows: 1. The inverted microscopic observation revealed a poorly defined cytoplasm at $2000ng{\sim}3000ng/ml$, indistinct nucleus, and apoptosis. 2. The Growth of cancer cells was decreased at 1000ng/ml of cyclosporin-A. No cancer cell growth was observed at over 2000ng/ml concentration of cyclosporin-A, and at one week, growth of cancer cells was ceased. 3. The MTT assays were decreased as cyclosporin-A concentration was increased. This means that the activation of succinyl dehydrogenase in mitochondria was decreased following administration of cyclosporin A. 4. A result of RT-PCR showed that amount of mRNA of VDAC-2 was decreased half times at a cyclosporine-A concentration of 2000ng/ml. In bcl-2, amount of mRNA was significantly decreased 1/5 times at 2000ng/ml. caspase-9, however, showed slight increase compared to the control group. From the results obtained in this study, administration of cyclosporin-A to the cell lines of oral squamous cell carcinoma induced alterations in morphology and growth of the cells as its concentration increased. Since apoptosis related factors such as VDAS-2, bcl-2, and caspase-9 also showed distinct alterations on their mRNAs, further research on cyclosporin A as an anti-cancer agent will be feasible.

• Journal of Pharmaceutical Investigation
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• v.32 no.2
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• pp.135-140
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• 2002

Cefadroxil is a semi-synthetic cephalosporin active against many Gram-positive and Gram-negative bacteria. The drug has been used for the treatment of the urinary and respiratory tract infections when caused by susceptible strains of the designated microorganism. The purpose of the present study was to evaluate the bioequivalence of two cefadroxil capsules, Duricef (Bo Ryung Pharmaceutical Co. Ltd.) and Hanacef (Korean Pharmaceutical Co. Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The cefadroxil release from the two cefadroxil capsules in vitro was tested using KP VII Apparatus II method with various different kinds of dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty four normal male volunteers, $21.58{\pm}2.43$ years in age and $70.74{\pm}10.29$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one capsule containing 500 mg as cefadroxil was orally administered, blood was taken at predetermined time intervals and the concentrations of cefadroxil in serum were determined using HPLC with UV detector. The dissolution profiles of two cefadroxil capsules were very similar at all dissolution media. The pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences in $AUC_t,\;C_{max}\;and\;T_{max}$ between two capsules based on the Duricef were 0.05%, -5.29% and 4.53%. There were no sequence effects between two capsules in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) $(e.g.,\;log(0.95){\sim}log(1.05)\;and\;log(0.87){\sim}log(1.02)$ for $AUC_t\;and\;C_{max}$, respectively). The 90% confidence interval using untransformed data was within ${pm}20%$ $(e.g.,\;-6.75{\sim}15.74\;for\;T_{max})$. All parameters met the criteria of KFDA guideline for bioequivalence, indicating that Hanacef capsule is bioequivalent to Duricef capsule.