• KSBB Journal
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• v.14 no.3
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• pp.328-336
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• 1999

A green microalga, Chlorella vulgaris UTX 259, was cultivated in a bench-scale raceway pond. During the culture, 15%(v/v) $CO_2$ was supplied and industrial wastewater discharged from a steel-making plant was used as a culture medium. In a small scale culture bottle, the microalga grew up to 1.8 g $dm^{-3}$ of cell concentration and ammonia was completely removed from the wastewater with an yield coefficient of 25.7 g dry cell weight $g^{-1}\;NH_3-N$. During the bottle-culture, microalga was dominant over heterotrophic microorganisms in the culture medium. Therefore, the amount of carbon dioxide fixation could be estimated from the change of dry cell weight. In a semi-continuous operation of raceway pond with intermittent lighting (12 h light and 12 h dark), increase of dilution rate resulted in increase of the ammonia removal rate as well as the $CO_2$ fixation rate but the ammonia removal efficiency decreased. Ammonia was not completely removed from the medium (wastewater) of raceway pond which was operated in a batch mode under a light intensity up to 20 klux. The incomplete removal of ammonia was believed due to insufficient light supply. A mathematical model, capable of predicting experimental data, was developed in order to simulate the performance of the raceway pond under the light intensity of sun during a bright daytime. Simulation results showed that the rates of $CO_2$ fixation and ammonia removal could be enhanced by increasing light intensity. According to the simulation, 80 mg $dm^{-3}$ of ammonia in the medium could be completely removed if the light intensity was over 60 klux with a continuous lighting. Under the optimal operating condition determined by the simulation, the rates of carbon dioxide fixation and ammonia removal in the outdoor operation of raceway pond were estimated as high as $24.7 g m^{-2} day^{-1}$ and $0.52 g NH_3-N m^{-2} day^{-1}$, respectively.

• Korean Journal of Heritage: History & Science
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• v.53 no.1
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• pp.24-33
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• 2020

In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.468-474
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• 1993

A dehydrating sheet comprises polymeric water absorber. which are packed in a semipermeable cellophane film bag allowing selective permeation of water. This sheet dehydration is quite different from conventional drying method such as sun drying, hot-air blast drying and cold air blast drying in a sense that samples are dried without heat treatment. As a part of the studies to develope a new processing method for effective utilization of dark muscle fishes, the preparation of a good quality salted and semi-dried mackerel by the dehydrating sheet was attempted. The dehydration time for preparation of a salted and semi-dried mackerels containing approximately equal moisture content were revealed $180{\sim}510min$ in conventional drying method and $90{\sim}160min$ in this sheet dehydration, respectively. The moisture and histamine contents of those salted and semi-dried mackerels were $59.4{\sim}62.4%$ and $2.5{\sim}3.6 mg/100g$, respectively. The changes in peroxide value, fatty acid composition, brown pigment formation, myofibrillar protein solubility and Ca-ATPase activity during processing of the salted and semi-dried mackerel prepared by the sheet dehydration were more lower than those of products prepared by conventional drying methods. Therefore, these result showed that the quality of a salted and semi-dried mackerel prepared by the sheet dehydration was imperial to that of those products by conventional drying method.

• Journal of Mushroom
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• v.10 no.4
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• pp.184-190
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• 2012

Monitorings and management experiment of adult Lycoriella ingenua (Diptera: Sciaridae) in artificial sawdust grown shiitake mushroom cultivation were carried out by using yellow sticky traps and Hypoaspis aculeifer (Acari: Laelapidae) at Hwaseong, Buyeo and Cheongwon in 2012. The larvae of L. ingenua reduced commercial value of the mushroom by direct eating or retarding the growth of mushroom by spongifying the sawdust medium. The number of L. ingenua caught by traps showed the highest peak in late september resulting in 127.5~1,025.7, 87.4~743.6 and 133.7~650.4 individuals per trap in Hwaseong, Buyeo and Cheongwon, respectively. Damage rate of fruiting bodies in shiitake mushroom by L. ingenua were 7.7~30.3% in Hwaseong, 6.7~25.3% in Buyeo and 5.3~26.0% in Cheongwon and showed the highest peak in late september. L. ingenua were effectively controlled when 30.3 individuals of H. aculeifer per $m^2$ inoculated for three time with 7 to 14 days of interval. In Hwaseong, Buyeo and Cheongwon, density of L. ingenua which were caught on the yellow sticky traps were 168.2, 126.1, 132.5 individuals, respectively. And, damage rate of fruiting bodies by L. ingenua were 5.9%, 5.5% and 5.4% respectively. Both of the L. ingenua density and damage rate of mushroom reduced more than 60% in all experimental site in contrast to the control treatment.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.75-84
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• 2011

We examined the effect of the turbid water on the periphytic diatom community in an artificial stream system. The artificial stream was constructed with transparent acryl and composed of four channels. Each channel ($20\;cm{\times}200\;cm{\times}40\;cm$) was supplied continuously with eutrophic lake water. In order to the freely colonize and grow diatoms, artificial substrate was installed with commercial slide glass soaked in 1% agar. Prior to introducing turbid water, the artificial stream was operated with lake water for 6 days to permit the propagation of diatom community on the substrates. The turbid water prepared with sediment sieved with ${\varphi}$ $64\;{\mu}m$ at $2\;g\;L^{-1}$ (final concentration, 300 NTU) was provided daily for 50 minute duration. The experiment was conducted for 7 days with manipulated experimental condition of light ($50{\sim}80\;{\mu}mol\;m^{-2}s^{-1}$, light:dark=24:0), temperature ($10{\pm}1^{\circ}C$), and flow rate ($0.31\;cm\;s^{-1}$). Sampling and analysis were conducted daily for water quality and diatom. Turbidity of the water varied 162.2~173.2 NTU during the experiment. After introduction of turbid water, DO, pH and TN were decreased, while SS and TP increased significantly. A total of 14 genera and 47 species of diatoms was observed on the artificial substrates during the experimental period. Of these, Navicula appeared to be a most dominant genus with 10 species, followed by Cymbella (6 species), Fragilaria (6 species) and Gomphonema (5 species). Achnanthes minutissima was the most dominant species (>70% of total frequency) in both control and treatment experiments. Increase in diatom abundance lasted for three days since turbid water introduction, after that they gradually decreased by the termination of the experiment. These results suggest that frequent supply of highly-concentrated turbid water significantly decreases the periphytic diatom community, and retard the recovery of the stable food-web within the stream.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.163-172
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• 2007

This study was designed to investigate that inorganic germanium $(GeO_2)$ did not exist in germanium-fortified yeast or obtained to non-detectable value by current analytical methods and equipments. For this purpose, we achieved $GeO_2$ qualitative analysis protocol which could be the scientific basis of the study. Since reddish brown precipitate was formed from the reaction of $GeO_2$ with 1 equiv $NaBH_4$, and dark brown precipitate was also formed from the reaction of $GeO_2$ with 2 equiv $NaBH_4$, $GeO_2$ was qualitatively analyzed by observing these particular colored-precipitates. Because no color change was showed from the reaction between $NaBH_4$ and $SiO_2$, the color change could be caused by charge transfer transition on Ge-O and B binding properties. The reaction between $NaBH_4$ and germanium-fortified yeast did not show any color change and precipitate formation which meant no $GeO_2$ existed in germanium-fortified yeast. The reaction between $NaBH_4$ and supernatant specimen collected from the outside of dialysis membrane (MWCO 1,200 dalton) did not show any color change and precipitate formation. Therefore, we considered that the both germaniums in and outside of the dialysis membrane were organic germaniums. Germanium-fortified yeast which was biosynthesized organic germanium can be applied not only as a new functional material for improving health, prevention and treatment of chronic degenerative diseases including cancers, and the regulation of immune system, but also as a new materials.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.4
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• pp.95-113
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• 2009

Objectives : Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) is a hair care product which is composed of ten plant extracts used in oriental medicine. This study was carried out to investigate the effects of Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) on hair regrowth and cytokine changes in a shaving model of C57BL/6 mice. Materials and Methods : Five-week-old mice were acclimated for 1 week at a temperature between $21-23^{\circ}C$, 40-60% relative humidity, and 12h of a light/dark cycle before beginning of the experiment. There were three experimental groups including 50% ethanol (EtOH, control), a positive control of 3% Minoxidil, and 30% Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) in 50% ethanol in 18 female mice. The test compounds were topically treated once a day over 12 days. The hair regrowth was photographically and histologically determined during the experimental period of 12 days. Revelation of EGF, $TGF-{\beta}1$ and IL-6 in hair follicle were also determined using immunohistochemistry. In addition to that, IL-6, $TNF-{\alpha}$, and $IL-1{\beta}$ in skin tissue were determined using enzyme-linked immunosorbent assay(ELISA). Results : Hair regrowth in 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups was promoted earlier and faster than the control group. Concentrations of hairs and thick-hair ratio in 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups were promoted than the control group. EGF was moderately positive in hair follicle of 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups, but negative in the control group. $TGF-{\beta}1$ was not significantly difference between the groups. IL-6 in hair follicle of Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) group was negative, but weakly positive in 3% Minoxidil and control group. IL-6 and $IL-1{\beta}$ in skin tissue were significantly decreased in Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) group, but there was not significantly decreased in 3% Minoxidil and control group. $TNF-{\alpha}$ in skin tissue was significantly decreased in 3% Minoxidil and Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) groups. Conclusions : These results suggest that Saengbal-eum-II($Sh{\bar{e}}ngf{\grave{a}}-y{\breve{i}}n-ll$) has hair growth promoting activity and it can be used for treatment of alopecia. And these effects relate to EGF revelation of hair follicle and a decrease IL-6, $TNF-{\alpha}$, and $IL-1{\beta}$ in skin tissue.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.185-202
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• 2020

The diapause induction season in Ostrinia furnacalis (Lepidoptera: Crambidae) was estimated in Suwon. Three batches of adult generations were observed, the first one from early May to early July, the second from early or mid-July to early or mid-August, and the third from mid-August to October. In outdoor larval rearing, colony rearing occurring from mid-July to mid-August produced both non-overwintering and overwintering larvae, whereas late-reared colonies produced only overwintering larvae. Larvae collected during July and August in maize fields produced both non-overwintering and overwintering larvae, whereas late-collected larvae produced only overwintering larvae. The results indicated that O. furnacalis has a bi- or trivoltine complex life cycle in this area. In the laboratory, when larvae of all instars within 9 h after molting were first treated to a diapause induction condition (11:13 h = light:dark photoperiod and 20℃), almost all larvae were induced to diapause. However, when similar treatments were conducted age-specifically for the 5th instar larvae, diapause induction rates in 3- and 4-day-old larvae of the 5th instar decreased. In contrast, when larvae were subjected to the diapause induction treatment only during the periods from the hatching stage to the 2nd, 3rd, and 4th instar, almost all larvae were not induced to diapause. The results suggest that the early age of the 5th larval instar is the last stage for sensitivity to diapause induction stimuli. In the diapause-induced larvae, hemolymph trehalose content increased and body supercooling points dropped, compared with those in non-diapause larvae.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.363-370
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• 2018

The succulent plants of Echeveria genus are in increasing demand worldwide, but it is difficult to supply good quality young plants throughout the year because propagation efficiencies are depend on cultivar and environmental factors. This study was carried out to investigate the propagation efficiencies of leaf cutting in Echeveria cultivars at different LED light qualities in a closed-type plant factory system. Leaf cuttings cut from stock plants of six difficult-to-propagated cultivars 'Afterglow (AG)', 'Berkeley Light (BL)', 'Mason (MS)', 'Subsessilis Light (SL)', 'Cream Tea (CT)', and 'Ben Badis (BB)' were put into cutting media in the plant factory system maintained at a temperature of $24{\pm}2^{\circ}C$ and relative humidity of $60{\pm}10%$, and watered with over-head irrigation twice a week. Cuttings were irradiated with sole or mixed red (R, 660 nm), blue (B, 450 nm), green (G, 530 nm), and far-red (FR, 730 nm) LEDs as follows: R10, R8+B2, R5+B5, R7+B2+FR1, and R7+B2+G1. PPFD just above the cuttings was $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and photoperiod was 16/8 (light/dark) hours. As a result, propagation efficiencies were dependent on cultivar. Rooting and shooting were relatively easy in 'SL' but shoot formation in 'AG' was very difficult. Light qualities from LEDs also affected plant regeneration. Light conditions with a higher ratio of B, R5+B5, R7+B2+FR1, and R7+B2+G1, promoted shoot formation and growth but inhibited rooting and root growth. R10 and R8+B2 with a higher ratio of R promoted rooting and root growth and inhibited shoot formation and growth of cuttings. In addition, the treatment with FR increased leaf size and biomass of the all plants. Therefore, further studies are needed to investigate the optimum compositions of LED light quality for the improvement of leaf cutting efficiency in difficultto-propagated Echeveria cultivars.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.257-265
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• 2015

Heat conditioning at an early age has been known to help chickens cope with heat stress later in life. The present study was conducted to determine the effects of heat conditioning at 5 days of age in broilers repeatedly exposed to high ambient temperature later in life. A total of 256 day-old Arbor Acre boiler chicks were housed in two identical rooms with a 23-h light/1-h dark cycle and provided with feed and water ad libitum. At 5 days of age, the birds in one room were exposed to $37^{\circ}C$ for 24 hours, while those in the other room served as controls. On day 21, half of the birds in each room were moved into the other room so that each room contained both control and heat-conditioned birds. After a 7-day adaptation period, the birds in one room were exposed to high ambient temperature ($21^{\circ}C{\rightarrow}31^{\circ}C$) for 3 days, whereas those in the other room were kept at normal temperature. The same 3-day exposure to high ambient temperature was repeated two weeks later. Hence, there were four treatment groups (CON+CON: control+control; CON+HS: control+high ambient temperature; HC+CON: heat conditioning+control; and HC+HS: heat conditioning+high ambient temperature). Repeated heat stress resulted in decreased feed intake, water intake, body weight gain, and spleen weight (p<0.05) and increased rectal temperature (p<0.05), mortality, and plasma corticosterone concentrations. The relative weight of the spleen was increased in the heat-conditioned group (p<0.05). Plasma biochemicals were also influenced by high temperature. Thus, no beneficial effects of heat conditioning at an early age were detected in broilers repeatedly exposed to high ambient temperature later in life.