• Mycobiology
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• v.45 no.3
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• pp.129-138
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• 2017

In this study, we aimed to characterize fungal samples from necrotic lesions on collar regions observed in different sweetpotato growing regions during 2015 and 2016 in Korea. Sclerotia appeared on the root zone soil surface, and white dense mycelia were observed. At the later stages of infection, mother roots quickly rotted, and large areas of the plants were destroyed. The disease occurrence was monitored at 45 and 84 farms, and 11.8% and 6.8% of the land areas were found to be infected in 2015 and 2016, respectively. Fungi were isolated from disease samples, and 36 strains were preserved. Based on the cultural and morphological characteristics of colonies, the isolates resembled the reference strain of Sclerotium rolfsii. Representative strains were identified as S. rolfsii (teleomorph: Athelia rolfsii) based on phylogenetic analysis of the internal transcribed spacer and large subunit genes along with morphological observations. To test the pathogenicity, sweetpotato storage roots were inoculated with different S. rolfsii strains. 'Yulmi' variety displayed the highest disease incidence, whereas 'Pungwonmi' resulted in the least. These findings suggested that morphological characteristics and molecular phylogenetic analysis were useful for identification of S. rolfsii.

• Journal of Plant Biology
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• v.17 no.1
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• pp.15-21
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• 1974

The most commonly grown economical and flue-cured tobacco cultivar Yellow Special A was used in pot-culture tests in order to study Ethrel (2-chloroethyl phosponic acid) effects on accelerating maturity of tobacco leaves in relation to the most adequate level of the chemical useful for field growing, nitrogen level in soil for the most pronounced response, and the most suitable spray period during the growth stages of pre-, post- and topping periods. The following conclusions, thus, were obtained from the present studies; 1. 500ppm Ethrel spray was reconfirmed to be adequate in the practical applications, although the extent of yellow-ripening of tobacco leaves was increased as the Ethrel level increased. The highest leevel treated resulted in causing chemically damaged lesions on leaves and early defoliation. 2. Ethrel-treated leaves showed deeper yellowish tinge to them than those without treatment, while different levels of the chemcial had less influence on the tinge. 3. An adequate level of nitrogen supply to plants favored the Ethrel response, whereas either very low or high level of nitrogen in the soil lowered the chemical effect on accelerating the yellow-ripening. When carbohydrates versus total nitrogen ratio became relatively high, the condition brought out some outstanding Ethrel effects. 4. Chlorophyll level of leaves increased as soil applications of nitrogen level increased, and that also increased carotenoid level of the tobacco leaves. Ethrel-treated leaves showed deeper orange tinge than those without treatment, while the highest level of nitrogen application showed the deepest orange tinge to tobacco leaves. 5. Pre-topping treatment (12 days before topping and flowering) resulted in almost no Ethrel response, and that treatment right on the day of topping, showed response of yellow-leaf ripening at nearly bottom-half leaves of a tobacco plant. The post-topping treatment (12 days after topping) made plants showing full response of Ethrel from bottom to the top leaves of tobacco plant in accelerating the leaf maturity. 6. The extent of Ethrel responses on accelerating yellow-ripening of tobacco leaves was discussed for the modifying influences brought about by certain environmental factors. Discussions were also made about the possible practical applications (particularly for pre-rice planting) and quality difference that may be caused by such growth environments.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.337-341
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• 1998

The morphological and cultural characteristics of alkalophilic Coryneform bacteria TU-19 were investigated at various pHs. This bacterium showed normal growth pattern at $pH\;9.0{\sim}10.0$, but the cell growth was completely inhibited at extreme pH (12.0 or more). Interestingly, at pH 8.0 the morphology of the bacterial cells seems to form convoluted filaments during the exponential growth phase while at pH 10.0, the optimal pH for the growth of this organism, the bacteria grew with variable paired or single forms, and straight rods during growth stages. Growing in alkaline media $(pH\;9.0{\sim}11.0)$, it adjusted the pH of the culture media to around pH 8.5 by itself.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.1003-1012
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• 2012

The gonadosomatic index (GSI), sex steroid hormones and gonadal development of roughscale sole Clidoderma asperrimum cultured in indoor tank were investigated to evaluate its sexual maturation and reproductive cycle. The highest GSI values of female and male were $6.91{\pm}4.03$ (May) and $0.16{\pm}0.08$ (August), respectively. The reproductive cycle would be classified into four successive developmental stages: growing stage (December to February), maturation stage (March to April), ripe and spawning stage (May to June), recovery and resting stage (July to November). The highest plasma testosterone (T) and estradiol-$17{\beta}$ ($E_2$) levels of female were $259.4{\pm}76.8$ and $633.3{\pm}182.5$ pg/mL, respectively in May. Also $17{\alpha}$, $20{\beta}$-dihydroxy-4-pregen-3-one ($17{\alpha}$, $20{\beta}$-OHP) levels of female peaked in April before spawning season ($244.2{\pm}42.5$ pg/mL). The highest plasma testosterone (T) and 11-ketotestosterone levels of male were $231.0{\pm}46.0$ and $273.9{\pm}54.5$ pg/mL, respectively in April. But there was no significant difference in $17{\alpha}$, $20{\beta}$-OHP.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.71-79
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• 2020

In recent years, Korean consumption trends have undergone rapid changes. Also, subscription economy has emerged and is growing as a new shopping method. The purpose of this study was to verify the relationship between consumer attitude and intention to continue to use of the consumption value of subscription service based on subscription economy. To this end, we analyzed the structural equation modeling for 300 consumers who used HMR products through subscription services. The analysis results are as follows. First, consumption value (functional, emotional, social and monetary) of HMR products perceived by subscribers had a significantly positive effect on consumer attitude except for monetary value. Second, consumer attitude was found to have a positive effect on consumers' intention to continue to use. This study contributes to the development of academic theories related to the subscription service in the early stages and provides managerial implications for HMR-related companies that want to utilize subscription service.

• Korean Journal of Environment and Ecology
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• v.19 no.1
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• pp.1-8
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• 2005

The removal affect of nitrogen and phosphorus were analyzed using a Acorus calamus var. angustatus. The nutrient concentration, growth stage of plants and the storage time of polluted water were considered. The results of this study were as follows: after an hour the content of nitrogen and phosphorus were considerably reduced in the Acorus calamus var. angustatus, while after two-four hours the rate of reduction was extremely low. This situation was the same in the early growth stage, growing stage and highest growth stage of the plant. The removal rate of nitrogen and phosphorus with the Acorus calamus var. angustatus was higher, when these two minerals remained in high levels of water. The Acorus calamus var. angustatus was more effective to remove nitrogen than that of phosphorus. The plant removed the most nitrogen and phosphorus when in the highest growth stage, but this was not clear in the growth stages. The removal rate was higher, in the case of moving polluted water to other plants after two days, than in the case of four days of growth in the same plants.

• Journal of Digital Contents Society
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• v.18 no.3
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• pp.577-584
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• 2017

Despite growing participation of many researchers, the cases of applying the transformative emotional display technology using physical materials and media are still in its early stages and the concept and structure are not properly established in Korea. The emerging global trend of physical display shows a possibility of new digital signage using emotional flip display. In this context, this study attempts to develop related element technology necessary in physical flip display and electromagnetic rotation module along with the integration platform of aesthetic arbitrarily-shaped display. The found results will be applied in researching the contents for the main subject which will be exhibited at the EXPO 2017 in Astana. It is to build up the foundation pioneering the localization of associated industry by means of diverse technological breakthroughs including flip-display technology, electromagnetic module technology, real-time video inter-working technology, high-speed rotation module technology, and transformative 3D frame technology.

• 대한생식의학회:학술대회논문집
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• 2000.06a
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• pp.13-28
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• 2000

Human spermatozoa exhibit a capacity to generate ROS and initiate peroxidation of the unsaturated fatty acids in the sperm plasma membrane, which plays a key role in the etiology of male infertility. The short half-life and limited diffusion of these molecules is consistent with their physiologic role in key biological events such as acrosome reaction and hyperactivation. The intrinsic reactivity of these metabolites in peroxidative damage induced by ROS, particularly $H_2O_2$ and the superoxide anion, has been proposed as a major cause of defective sperm function in cases of male infertility. The number of antioxidants known to attack different stages of peroxidative damage is growing, and it will be of interest to compare alpha-tocopherol and ascorbic acid with these for their therapeutic potential in vitro and in vivo. Both spermatozoa and leukocytes generate ROS, although leukocytes produce much higher levels. The clinical significance of leukocyte presence in semen is controversial. Seminal plasma confers some protection against ROS damage because it contains enzymes that scavenge ROS, such as catalase and superoxide dismutase. A variety of defense mechanisms comprising a number of antioxidants can be employed to reduce or overcome oxidative stress caused by excessive ROS. Determination of male infertility etiology is important, as it will help us develop effective therapies to overcome excessive ROS generation. ROS can have both beneficial and detrimental effects on the spermatozoa and the balancing between the amounts of ROS produced and the amounts scavenged at any moment will determine whether a given sperm function will be promoted or jeopardized. Accurate assessment of ROS levels and, subsequently, OS is Vital, as this will help clinicians both elucidate the fertility status and identify the subgroups of patients that respond or do not respond to these therapeutic strategies. The overt commercial claims of antioxidant benefits and supplements for fertility purposes must be cautiously looked into, until proper multicentered clinical trials are studied. From the current data it appears that no Single adjuvant will be able to enhance the fertilizing capacity of sperm in infertile men, and a combination of the possible strategies that are not toxic at the dosage used would be a feasible approach.

• Plant Resources
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• v.3 no.2
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• pp.105-109
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• 2000

This study was carried out to find a useful mushroom at Chungnam Agricultural Research And Extention Service. Twenty materials used were collected from domestic and exotic area. These races were compared bontanical characteristics to leading varieties by PCR-RAPD methods. Mycelial growth temperature of Chongpung and Myongwol were at 20 to 25 $^{\circ}C$ and 25 to 30 $^{\circ}C$ at PDA medium, respectively mycelial growth of these varieties were similiar at pH 6.5 to 7.5. In case of mushroom cultivation temperature ranges, Chongpung was at 5 to 26$^{\circ}C$ and Myongwol was at 7 to 28$^{\circ}C$, but the optimum temperature range of these were appeared at 15 to 19$^{\circ}C$. Culture temperature of these was 23$^{\circ}C$ and period of mycelial culture was needed 23 to 24 days under 850cc/pp, while was needed 11 to 12 days at waste cotton medium. Cap color of these at first inducing mushroom was all dark blue, but at late growing stages Chongpung was shown as grey, and Myongwol was shown as dark grey. Yield of Chongpung was appeared as 46kg/3.3$m^2$ and that of Myongwol was 41kg /3.3$m^2$, while Chunchu No2 as check was 40kg/3.3$m^2$. Results from PDA medium and PCR-RAPD analysis two of these were different from others.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.126-136
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• 2020

Recently, unmanned aerial vehicles (UAV, Drone) are highly regarded for their potential in the agricultural field, and research and development are actively conducted for various purposes. Therefore, in this study, to present a framework for tracking research trends in UAV use in the agricultural field, we secured a keyword search strategy and analyzed social network, a methodology used to analyze recent research trends or technological trends as an analysis model applied. This study consists of three stages. As a first step in data acquisition, search terms and search formulas were developed for experts in accordance with the Keyword Search Strategy. Data collection was conducted based on completed search terms and search expressions. As a second step, frequency analysis was conducted by country, academic field, and journal based on the number of thesis presentations. Finally, social network analysis was performed. The analysis used the open source programming language 'Python'. Thanks to the efficiency and convenience of unmanned aerial vehicles, this field is growing rapidly and China and the United States are leading global research. Korea ranked 18th, and bold investment in this field is needed to advance agriculture. The results of this study's analysis could be used as important information in government policy making.