• Korean Journal of Environment and Ecology
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• v.31 no.5
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• pp.444-454
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• 2017

There are many ongoing studies of infectious diseases as the major factor responsible for global declining of the amphibian population. Although some point out the amphibian rearing facilities like frog farms as one of the important sources of harboring and spreading amphibian infectious pathogens in the wild, there have been few related studies in South Korea. In this study, we investigated the bacterial and fungal colonies on the skin and in the internal organs of frogs and tadpoles collected inside and outside of Dybowski's brown frog farms in Inje, Goesan, and Gongju to compare the difference according to the region and between inside and outside the farm. We also intended to classify the bacteria collected from the tadpoles into species by analyzing 16s rDNA gene sequences. The result showed that the number of bacterial colonies found in the skin and gut of frogs and the number of fungal colonies found in the skin and liver of frogs collected in Goesan was significantly greater than those in the frogs in Inje. However, there was no difference between the frogs collected inside and outside of farms in both regions. In the case of tadpoles, the number of fungal colonies in the tadpoles collected from Gongju was greater than that in the tadpoles collected from Inje. The comparison of inside and outside frog farms showed that there were more bacterial colonies on the skin of the tadpoles collected from inside than outside the frog farm in Inje and more bacterial colonies in the organs of the tadpoles collected from outside than inside the farm in Gongju. The frogs with higher condition factor (body weight/snout-vent length*100) showed fewer bacterial colonies on the skin and fewer fungal colonies in the heart, but there were no significant relationships in tadpoles. We identified the total of 15 genera and four phyla of bacteria, but the difference according to regions and between inside and outside farm was not evident. The result of this study indicates that the different conditions according to the locality of farm and between inside and outside farm cause the difference in the population sizes of bacterial and fungal colonies and that it can affect the overall health condition of Dybowski's brown frogs in the farm. Moreover, the result suggests that effective disease control in the facility is greatly necessary to ensure successful operation of amphibian rearing facility and to prevent the possible spread of diseases from the facility to the wild.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.3_4
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• pp.113-120
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• 1971

In 1971, about 150,000 fingerlings of grass and silver carps were produced and distributed from the Fishculture Laboratory of Pusan fisheries College. The adults Were those transplanted from Japan in 1963. Findings during the process of this production are summarized as following : 1. Brood fish must be handled with a great care during the catching, hormone injection and maturity inspection so as the fish are not injured, otherwise, the eggs would not mature perfectly. Scale fall also affects significantly. 2. The amount of pituitary to be injected is preferable to be 2 to 3 times or more in donor's body weight to obtain good results. 3. The eggs should be spawned or stripped and inseminated as soon as mature. If the spawning is delayed the eggs become overmature and the hatching rate decreases significantly. 4. The water once used for the incubation of eggs should not be reused. The eggs under hatching process were melted away when water once used for incubation was reused. 5. A great care must be paid to keep water in quality when the net cage culture system is employed for raising fry or early fingerlings of Chinese carps. The best method to keep water in quality is to supply water in the cage continuously through a pipe or hose. 6. Heavy outbreaks of Spirogyra occured when clear well water was supplied into the cage, and a great number of fry or fingerlings were trapped or entangled resulting in a significant decrease of fish under rearing. It was prevented when moderately bloom-ed pond water was supplied into the cage. 7. Silver carp fry are usually captured and transported in the cool season because they can not be handled in the warm season owing to a high mortality, but cage cultured small size fingerlings ranging from 1.5 to 2 cm in total length are easily handled and transported even in the hot summer season, thus it enables the fish farmers to start growing them one season earlier.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.302-308
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• 1990

This study was conducted to determine the effects of mycorrhizal inoculation and ortet ages on the rooting of Quercus acutissima cuttings. The cuttings taken from 12-week-, 2-year-, 4-year-, and 20-year-old plants were rooted in mid summer in the rooting medium (vermiculite 2 : peatmoss 1 by volume) with or without Pisolithus tinctorius (Pt) and Glomus sp. inocula and IBA under intermittent misting system in an open shed. The average percentages of rooting were about 82%, 49%, 29%, and 13% for cuttings taken from 12-week-, 2-year-. 4-year-, and 20-year-old seedlings, respectively. Pt inoculation, enhanced rooting of cuttings at all age classes, except 12-week-old seedlings, with the highest enhancement(22%) observed in cuttings taken from 20-year-old trees. The highest percentage of rooting in each age group eras 88.9% in 12-week-old seedlings treated with Pt plus 3.000ppm IBA, 75% in 2-Year-old plants with 1,000ppm IBA, 58.3% in 4-year-old plants with 3.000ppm IBA and 22% in 20-year-old plants. The addition of Glomus sp. fungus inoculum failed to enhance rooting. Pt mycorrhizal inoculation enhanced root dry weight, length, and diamter of adventitious roots at cuttings taken from 12-week- and 20-year-old trees, except the cuttings taken from 4-year-old seedlings. Rooted cuttings had more total nitrogen content in the leaves than unrooted cuttings, and the greater rooting response was associated with the higher phosphorus content in the leaves.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.421-429
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• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.

• The Journal of Korean Academy of Prosthodontics
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• v.19 no.1
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• pp.17-27
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• 1981

This study was conducted to determine the chemical composition and the mechanical properties of four commercially available low gold-based crown and bridge alloy produced in Korea. Four dental casting gold-silver-palladium alloys, i.e., A, B, C and D (code of alloys) were selected for the evaluation of chemical composition, ultimate tensile strength, elongation. values and Vickers hardness. The chemical composition of test specimens was analyzed by both emission spectrography and wet gravitation method with a 1.5gm of low gold ingot. The tensile properties and Vickers hardness was determined with cast specimens treated in following three conditions; as-cast, softening heat treatment and hardening heat treatment. The tensile testing bars were cast in accordance with the model designed by Gettleman and Harrison (1969) which was modified from the A. D. A. Specification No. 14 for dental chromium-cobalt casting alloy. Nine tensile test specimens were made from a split silicone mold for each of the test alloys to the size of 2.5mm in diameter and a gauge length of 10mm. All four alloys were handled in accordance with conventional methods used in Type III gold alloys. Ultimate tensile strength and elongation were measured on an Instron Universal Tensile Testing Machine (Model 1125, Japan) operated at a crosshead rate of 0.1cm/min. Elongation values were measured using Digital Measuring Microscope (MS-152, FUSOH, Japan). Vickers hardness was determined with a Vickers Hardness Tester (Model VKH-l, Japan) at a 1.0kg load on a mounted tensile test specimen. The following results were obtained from this study; 1. All tested alloys were composed of Au, Ag, Pd, Cu, Zn and Fe in common. The composition rate of gold for all four alloys was found in the range of $42{\sim}47$ weight % as shown below. Alloy A; Au 45%, Ag 40.2%, Pd 5.76%, others 9.04%. Alloy B; Au 47.1%, Ag 29.03%, Pd 6.98%, others 16.92%. Alloy C; Au 45%, .Ag 26.9%, Pd 6.83%, others 21.07%. Alloy D; Au 41.8%, Ag 34.4%, Pd 6.95%, others 16.85%. 3. The ultimate tensile strength of the four alloys was in the range of $31{\sim}82kg/mm^2$. The test results were shown in the below order from the highest value; As-cast condition; D, B, C, A. Softening heat treament; B, C, D, A. Hardening heat treatment; D, B, C, A. 4. The test :results of the elongation rate for each alloy were in the range of $0.5{\sim}18%$. The test results were shown in the below order from the highest value; As-cast condition; A, D, B, C. Softening heat treatment; A, C, D, B. Hardening heat treatment; C, D, B, A. 5. Vickers hardness for each of the four alloys was in the range of $120{\sim}230$. The test results were shown in the below order from the highest value; As-cast condition; C, B, D, A Softening heat treatment; D, B, C, A. Hardening heat treatment; D, A, C, B. 6. There were no differences in the physical properties between as-cast condition and softening heat treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1253-1259
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• 2001

The purpose of this study was to investigate the effects of green tea catechin on change of bone tissue in long-term cadmium treated rats. Sprague-Dawley male rats weighing 100$\pm$10 g were randomly assigned to one normal group and three cadmium treated groups. Cadmium groups were classified to catechin free diet group (Cd-0C group), 0.25% catechin diet group (Cd-0.25C group) and 0.5% catechin diet group (Cd-0.5C group) according to the levels of catechin supplement. Animals were raised for 20 weeks. Cadmium were supplied as drinking water of 50 ppm Cd$^{2+}$. Effects of catechin were analyzed on changes of bony tissue in long-term cadmium treated rats by determining the accumulated cadmium in bone and bone mineral density and micro- photographs of bony tissue. The cadmium accumulation of tibia and femur were higher in Cd-treated groups than in normal group, but they was lowered by catechin supplementation. The bone mineral density (BMD) of tibia and femur in Cd-0C group was significantly lower than in normal group, but it of catechin supplemetation group was similar to normal group. Microphological changers were appeared under a light microscope and an electro microscope reveal no structural changes in bony spicules, marrow cell distribution and cellular morphology in all groups. The bone weight and length tend to decrease in Cd-0C groups. Catechin supplementation in long-term cadmium treated rats depressed the cadmium accumulation in bony tissue that led to improve the bone mineral density in tibia and femur.r.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.212-217
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• 2016

This study was conducted to investigate the effect of nursery period on growth and yield attribute of green papaya (var. Red lady). The nursery period was 3, 5, 7, 9, 11 and 13 months and the green papaya was transplanted on 15 April, 2015 in a non-heated greenhouse. The plant height, node number and fresh weight of nursery plant were increased as the nursery periods increased. The growth of green papaya with 13 months nursery period was better than those of other treatments. First harvest after transplanting was increased as the nursery periods were shorten. It took 137 days (18 August) at 13 months treatment, and 184 days (2 October) at 3 months treatment. The fruit length and diameter were smallest at 3 months treatment and there was no significant difference among other treatments. The fruit yield was also influenced by the nursery periods, the commercial yield was also increased as the nursery periods increased. The commercial yield was highest at 13 months treatment (3,172kg/10a), followed by 11 (2,247kg/10a) and 9 months treatment (2,357kg/10a). At 7 and 5 months treatment were 1,942kg/10a and 1,787kg/10a, respectively and the yield was lowest at 3 months treatment (1,443kg/10a). The commercial yield was significantly decreased under 7 months treatment. Although the harvest time of 11 months treatment was earlier than that of other treatments in non-heated greenhouse, 9 month treatment will be more recommendable for green papaya production because of operating costs.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.191-198
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• 2018

The objective of this study was to determine the effects of combination of air temperature and soil water contents on growth, physiological disorder rate, and yield of garlic. This experiments has been carried out in the typical plastic house (one side open and other side installed ventilation fans) which was maintained gradient air temperature (maximum different value of air temperature : $6^{\circ}C$). The excessive irrigation (EI) set at $0.34m^3/m^3$ soil moisture contents. The significant differences found in the growth parameters of garlics as affected by air temperature and soil moisture conditions. The plant height of garlic with combination of ambient $(A)+6^{\circ}C$ and optimal irrigation (OI; set at $0.22m^3/m^3$ soil moisture contents) treatments represented 47.4 cm/plant, which was the highest among all the tested treatments. The leaf length and width showed the greatest, which were 16.1 and 2.4 cm/plant, respectively, in $A+6^{\circ}C-OI$. The physiological disorder ratio was higher as 12.9% at $A+6^{\circ}C-OI$ and was not occurred at ambient temperature with EI compared with OI treatment. The bulb and clove weight were dramatically decreased at $A+6^{\circ}C$ temperature treatment. The yields were decreased by 51% in OI at $A+6^{\circ}C$ and $A+3^{\circ}C$ temperature treatment. Those results indicated that yields were decreased and ratio of physiological disorders was increased by high temperature treatments.

• Journal of Radiation Protection and Research
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• v.32 no.2
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• pp.65-69
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• 2007

The effects of bamboo (Phyllostachys nigra var. henenis Strapf) leaf extract (BLE) on the changes of ultraviolet (UV) light B radiation-induced apoptotic sunburn cell (SBC) and epidermal ATPase-positive dendritic cell (DC) in SKH1-hr or ICR mouse were investigated. The mice were treated with UVB ($200mJ/cm^2$) and were sacrificed 24 hours later. BLE (50 mg/kg of body weight) or vehicle (saline) was given i.p. at 36 and 12 hours before irradiation, and 30 minutes after irradiation. BLE cream (0.2%) or cream base (vehicle) was also topically treated at 24 hours and 15 minutes before irradiation, and immediately after irradiation. The skin of SKH1-hr mouse prepared from the back of untreated mice exhibited about 0.3 SBC/cm length of epidermis, and 24 hours after UV irradiation, the applied areas show an increased number of SBCs. But the frequency of UVB-induced SBC formation was significantly reduced by intraperitoneal injection (59.0%) and topical application (31.8%) of BLE extract. The numbers of DC in normal ICR mouse were $628.00{\pm}51.56\;or\;663.20{\pm}62.58\;per\;mm^2$ of ear epidermis. By 1 day after UVB treatment, the number of ATPase-positive $cells/mm^2$ were decreased by 39.0% or 27.1% in i.p. or topical application group with vehicle. The frequency of UVB ($200mJ/cm^2$)-induced DC decrease was reduced by treatment of BLE as 25.7% in i.p. group and 3.2% in topical application group compared with the irradiation control group. The results presented herein that BLE administration could reduce the extent of skin damages produced by UVB.

• The Korean Journal of Mycology
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• v.34 no.1
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• pp.39-53
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• 2006

This studies investigated the effect of concentrations of sodium chloride (NaCl) on occurrence and growth of fruitbody in oyster mushrooms, Pleurotus spp. Our experiments divided into two parts. When the water contents in substrate were added with sodium chloride solution in cotton waste box cultivation as a first experiment, the growth of mushroom was damaged as the concentration was increased, even though there was a little difference according to the strains. The yield in 1.0% NaCl solution was decreased to 72% compared to non-treated plot while that in 3.0% solution was only 2% of the non-treated plot. Morphological characteristics of mushrooms cultivated in substrate with the different concentration of the solution showed different results. For example, the size and thickness of pilei were not influenced by NaCl concentration, but the length of stipes and individual weight were much influenced. In plastic box cultivation filled with cotton waste, watering treatment with the different concentrations of sodium chloride solution, the second experiment, did not show any difference according to the concentration until 1.0% solution but there was a little difference according to the strains. The productivity of fruitbody started to decrease at 2.0% of the solution and the yield and quality of mushroom in 3.0% solution treatment were generally low. After the second flush, days for mushroom sprouting were generally prolonged in proportion to the solution concentration. Taken altogether, the second experiment did not show a clear effect as the case of the first experiment.