• Journal of Aquaculture
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• v.9 no.4
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• pp.445-452
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• 1996

Endogeneous activities of ${\beta}-galactosidase$-like enzyme in various tissues from several finfishes and shellfishes were examined by histochemical analysis based on X-gal staining and by fluorimetric measurement using 4-methylumbelliferyl-${\beta}$-D-galactoside (4-MUG). Species used in this study were 3 freshwater fishes, mud loach (Misgurnus mizolepis), common carp (Cyprinus carpio) and tilapia (Oreochromis niloticus) ; 3 marine fishes, olive flounder (Paralichthys olivaceus), stone flounder (Kareius bicoloratus) and marbled sole (Limanda yokohamae) ; and 4 shellfishes, abalone (Haliotis discus hannai), Pacific oyster (Crassoskra gigas), pearl oyster (Pinctada fucata martensii) and ark shell (Anadara broughtonii). The activities of ${\beta}-galactosidase$-like enzyme in all finfishes examined were significantly different among species, with the wide variations between tissues in a species. In general, the tissues such as kidney, intestine and liver were ones which showed the significantly higher values in 4-MUG fluorimetry and deeper staining patterns in X-gal analysis compared to other tissues. On the other hand, serum and muscle revealed the significantly lower activities than others did, regardless of species. Shellfishes were also found to have endogenous activities of ${\beta}-galactosidase$-like enzyme which were significantly varied depending on both species and organs in a species. Hepatopancreas from all shellfishes examined showed the deepest pattern in X-gal staining and also the highest value in 4-MUG analysis, while activities of ${\beta}-galactosidase$-like enzyme in adductor muscles and mantle muscles from all shellfish species in this study except Pacific oyster were negligible : Pacific oyster had the significant activity of this enzyme in muscle tissues. Putative endogenous lacZ fragment was amplified from both finfishes and shellfishes by polymerase chain reaction (PCR). The molecular size of PCR products was about 510 bp, and there was no difference in size among species examined.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.6
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• pp.659-681
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• 2001

Platelet-rich plasma(PRP) has been known to increase the rate and degree of bone formation by virtue of growth factors in concentrated platelets. Although its great healing effect on bone defect or pre-implantation site preparation in conjunction with bone substitute has been reported, the effect associated with implant is unknown. The purpose of this study was to investigate the effect of PRP on rapid osseointegration of endosseous dental implants in the rabbit tibiae. Twenty two adult female New Zealand white rabbits, weighing approximately 2.7-3.3kg, were used for this study. Twelve of the 22 animals were used for histomorphometric analysis and ten of the 22 were for removal torque test. Each animal received two implants in each tibia (two treated with PRP and two as control) and was given fluorochrome intramuscularly. For histomorphometric analysis, rabbits were divided into four groups according to the healing period. At 1 week, 2 weeks, 4 weeks and 8 weeks postoperatively, each three animals were sacrificed serially and the amount and rate of bone formation around dental implant were examined on the undecalcified sections under fluorescent microscope, polarized microscope and light microscope connected to a personal computer equipped with image analysis system. For removal torque test, rabbits were divided into two groups and removal torque tests were performed at 4 weeks, 10 weeks after implant placement. In total, 88 screw shaped, commercially pure titanium implants (Neoplant, Neobiotech, Seoul, Korea) were used in this study. Labeling pattern reflected differences of two groups in bone formation rate at each period. Histomorphometrically, PRP group showed significantly higher bone volume within threads compared to control group at 2 weeks ($70.30{\pm}4.96%$ vs. $50.68{\pm}6.33%$; P < .01) and 4 weeks ($82.59{\pm}5.94%$ vs. $72.94{\pm}4.57%$; P < .05 ). PRP group at 1, 2 and 4 weeks revealed similar degree of bone volume formation comparable to control group at 2, 4 and 8 weeks, respectively. On the other hand, while PRP group showed higher bone-implant contact ($47.37{\pm}8.09%$) than control group ($33.16{\pm}13.47%$) at 2 weeks, there were no significant differences between PRP group and control group for any experimental period. Removal torque values also showed no significant differences between PRP group and control group at any experimental period (P > .05). These findings imply that PRP could induce rapid, more bone formation around implant during early healing period and get faster secondary stability for reducing healing period, though it has not induced bone maturation enough to resist functional loading.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.514-525
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• 2006

Statement of problem: The color change of final restoration resulting from resin cement is variable since the amount of the tooth is prepared is minimum. Purpose: The purpose of this study was to compare the color accuracy of try-in paste and their corresponding resin cements and the color stability of restoration intermediated resin cement according to two shades of three products(Rely-X. Variolink II. Choice). Material and method: Color was measured for porcelain disk sample without try-in paste, and porcelain disk sample intermediated by try-in paste and resin cement, then color differences were calculated. Results : 1. Color difference(${\Delta}E^*$) between try-in paste and resin cement showed the lowest value at Variolink II and increased in the order Choice and Rely-X statistically significant, and $?E^*$ of three resin cements was greater in A3 then A1. 2. The values of ${\Delta}L^*$ and ${\Delta}a^*$ between try-in paste and resin cement was in the increasing order of Variolink II, Choice and Rely-X. The ${\Delta}b^*$ value was increased in this order Choice, Rely-X and Variolink II in A1 on the other hand Variolink II, Rely-X and Choice in A3. 3. Color difference(${\Delta}E^*$) before and after resin cement showed the lowest value at Variolink II and increased in the order Rely-X and Choice. Conclusion : Above result revealed that the colors of try-in paste and resin cement were more or less accurate in the range of 0.35-1.95 of color difference which was unnoticeable with human eye, and Variolink II was superior to the other resin cements in color accuracy.

• Ocean and Polar Research
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• v.26 no.3
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• pp.415-423
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• 2004

An experiment was conducted to investigate the differences of total ammonia nitrogen (TAN) excretion rates and feces production rates among the offsprings from cultured Japanese strain (JJ, mean BW; $17.1{\pm}0.1g$), intraspecific hybrid strain between cultured Japanese and selected Korean strain (JK, mean BW: $17.1{\pm}0.1g$) and selected Korean strain(KK, mean BW: $21.5{\pm}0.1g$) of red sea bream in order to compare their dietary protein utilization efficiency. Fish were hand-fed with a commercial diet containing 46.7% crude protein for 2 weeks, three times daily 09:00, 13:00 and 17:00. After daily feeding, the TAN excretion rates reached peaks of 49.03, 58.75 and 36.26mg/kg fish/hr for the JJ, JK and KK strain, respectively, during the daytime. The value of the KK strain was significantly lower than that of the JJ and JX shuin (P<0.05), however daily TAN excretion rates of the JJ, JK and KK strain were not different (P>0.05). When fish were fed at satiation after 4 days of starvation, TAN excretion rates reached the maximum values 4 hours after the feeding fur the KK (31.23 mg/kg fish/hr) and 6 hours after the feeding fur the JJ (44.19 mg/tg fish/hr) and JK strain (41.70 mg/kg fish/hr). After 3 days of starvation, the daily endogenous TAU excretion rates (ETE) for the JJ, JK. and KK strain were 286.91, 215.66 and 179.29mg/kg fish/day, respectively. The value of the KK strain was lower than that of the JJ and JK strain (P<0.05). The total feces production rates of the JJ, JK and KK strain were not significantly different, however the proportions of feces production rates by time for the JJ, JK and KK strain were different (P<0.05). As overall results, efficiency of dietary protein utilization of JJ, JK and KK seems to be different and KK strain could offer a desirable option for aquaculture purpose.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.411-417
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• 2017

Environmental and growth factors such as light intensity, vapor pressure deficit, and leaf area index are important variables that can change the transpiration rate of plants. The objective of this study was to compare the transpiration rates estimated by modified Penman-Monteith model and artificial neural network. The transpiration rate of paprika (Capsicum annuum L. cv. Fiesta) was obtained by using the change in substrate weight measured by load cells. Radiation, temperature, relative humidity, and substrate weight were collected every min for 2 months. Since the transpiration rate cannot be accurately estimated with linear equations, a modified Penman-Monteith equation using compensated radiation (Shin et al., 2014) was used. On the other hand, ANN was applied to estimating the transpiration rate. For this purpose, an ANN composed of an input layer using radiation, temperature, relative humidity, leaf area index, and time as input factors and five hidden layers was constructed. The number of perceptons in each hidden layer was 512, which showed the highest accuracy. As a result of validation, $R^2$ values of the modified model and ANN were 0.82 and 0.94, respectively. Therefore, it is concluded that the ANN can estimate the transpiration rate more accurately than the modified model and can be applied to the efficient irrigation strategy in soilless cultures.

• BMB Reports
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• v.40 no.3
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• pp.315-324
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• 2007

The novel $\alpha$-amylase purified from locally isolated strain, Bacillus sp. KR-8104, (KRA) (Enzyme Microb Technol; 2005; 36: 666-671) is active in a wide range of pH. The enzyme maximum activity is at pH 4.0 and it retains 90% of activity at pH 3.5. The irreversible thermoinactivation patterns of KRA and the enzyme activity are not changed in the presence and absence of $Ca^{2+}$ and EDTA. Therefore, KRA acts as a $Ca^{2+}$-independent enzyme. Based on circular dichroism (CD) data from thermal unfolding of the enzyme recorded at 222 nm, addition of $Ca^{2+}$ and EDTA similar to its irreversible thermoinactivation, does not influence the thermal denaturation of the enzyme and its Tm. The amino acid sequence of KRA was obtained from the nucleotide sequencing of PCR products of encoding gene. The deduced amino acid sequence of the enzyme revealed a very high sequence homology to Bacillus amyloliquefaciens (BAA) (85% identity, 90% similarity) and Bacillus licheniformis $\alpha$-amylases (BLA) (81% identity, 88% similarity). To elucidate and understand these characteristics of the $\alpha$-amylase, a model of 3D structure of KRA was constructed using the crystal structure of the mutant of BLA as the platform and refined with a molecular dynamics (MD) simulation program. Interestingly enough, there is only one amino acid substitution for KRA in comparison with BLA and BAA in the region involved in the calcium-binding sites. On the other hand, there are many amino acid differences between BLA and KRA at the interface of A and B domains and around the metal triad and active site area. These alterations could have a role in stabilizing the native structure of the loop in the active site cleft and maintenance and stabilization of the putative metal triad-binding site. The amino acid differences at the active site cleft and around the catalytic residues might affect their pKa values and consequently shift its pH profile. In addition, the intrinsic fluorescence intensity of the enzyme at 350 nm does not show considerable change at pH 3.5-7.0.

• Information Systems Review
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• v.9 no.1
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• pp.105-120
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• 2007

With the fast development of the Internet and the increasing dependence on information infrastructures, companies are faced with various information security threats such as information leakages, modifications, and information breaches. South Korea is one of the leading countries in the Internet usage, but is ranked relatively low when it comes to information security. In fact, many Korean firms have suffered financial losses and damaged corporate images from the information security breaches. However, because of the difficulties in quantifying the costs of the information security breaches, Korean companies tend to delay their investment decisions on information security. The purpose of this study is to measure the cost of information security breach and the economic value of security investment using the event study methodology. Our results show that the announcement of an information security breach negatively influenced the market value of the corresponding company. The effect was statistically significant at the significance level of p=0.05. The breached companies lose, on average, 0.86% of their market values on the day of the announcement - an average loss in market capitalization of $55 million. On the other hand, the investment on information security had no effect on the stock price or the market value of the firm.

• Journal of Life Science
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• v.21 no.8
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• pp.1183-1189
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• 2011

The present study is aimed at examining the effects of the physico-chemical environmental factors of water systems on water bloom at Homin and Gagok reservoirs in Pungcheon-Myeon, Andong, Gyeongsangbuk-do. The mean water temperature and the contents of chlorophyll-a, total-nitrogen, total-phosphorus and phosphate-phosphorus were higher at the Gagok reservoir. On the other hand, the pH mean value was higher at the Homin reservoir. The mean value of microelements (Na, K, Mg, Fe, Si) was higher at the Gagok reservoir. The cyanobacteria which was considered to be the cause of water bloom at the two reservoirs was Microcystis aeruginosa. It started to grow in May and showed the highest standing crop in August. Between the increase of standing crop of M. aeruginosa and the water quality, correlation values of $Na^+$ (r=-0.910, p<0.05), $Fe^{2+}$ (r=-0.855, p<0.05) and $Si^{4+}$ (r=0.989, p<0.01) at the Homin reservoir increased amount of standing crop. Meanwhile, at the Gagok reservoir, the contents of $Na^+$ (r=-0.776, p<0.05), $Si^{4+}$ (r=0.899, p<0.05) were highly related to the increase of standing crop. Interestingly, Si, which is the limiting factor for diatoms, has a high correlation with standing crop of cyanobacteria. In conclusion, the water blooming is caused not by a simple factor but a synergistic effect due to complex actions including high concentrations of nitrogen and phosphorus ions and many other environmental factors.

• The Korean Journal of Malacology
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• v.2 no.1
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• pp.13-25
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• 1986

One of the most medically important snail species of Korea is Semisulcospira spp., a member of the freshwater prosobranch family pleuroceridae. The parasites that these snails transmit to humans are mainly Paragonimus westermani and Metagonimus yokogawoi. On the other hand, Semisulcospira snails are edible as a foodstuff in Korea. The present study was first aimed to detect out residual pesticides in the snails collected at the endemic and non-endemic areas of paragonimiasis in Korea and to make relationship to the detectability of larval trematodes shed from the snails. In addition, water specimens from the habitats where the snails were collected were sampled and analysed to elucidate environmental conditions of the habitats. This malaco-ecological survey was done at 7 endemic and 3 non-endemic areas of paragonimiasis for about more than 2 years, May, 1984 through October, 1986. All the water smaples both from the endemic and non-endemic areas of paragonimiasis showed normal ranges of the criteria of upper freshwater streams, with lower B.O.D. (0.4~2.0 ppm) and higher D.O. values (9.5~11.0 ppm) than those in the large river systems Infection rate of digenetic trematodes in total snails collected was 6.7%, but no Paragonimus cercaria was detected out at all even in the endemic areas of paragonimiasis. The ecological factors affecting Paragonimus larvae in the snails were also discussed. A total of 9 chlorinated hydrocarbon pesticieds was targeted to detect out from the tissues of snails. Out of 9 pesticides, aldrin, beta-BHC, p, p-DDT, dieldrin, DDE, lindane, heptachlor and heptachlor epoxide were eluted from the snails. The highest levels of the pesticides were mostly detected out in the snails collected from the Donghae-Chun area of Haman and the Kangwha area of Kyongki-Do, where the lowest infection rates of trematode cercariae (0~0.5%) were revealed. The possibilities that the residual pesticides in the freshwater animals including Semisulcospira snails might be transferable to humans were also discussed.

• The Journal of Korean Association of Computer Education
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• v.15 no.5
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• pp.11-22
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• 2012

This study aimed to analyze applying TAM model the process that flow factors such as 'harmony of challenge and technology' exert effects on learners' attitudes of keeping learning in STEAM class employing robots. For the study, the 'Energy and Tools' chapter of the science textbook for the 6th grade's second semester was re-arranged, and applied for 189 students, and among them, only the 174 usable data were used for the analysis. As a result of analysis, students' learning immersion factor(factor of harmony of challenge and technology) had deeper effects on the factor of ease of learning than usefulness of learning and this in turn, had an effect on their intention to keep learning ultimately through the factor of value of learning as the study found. As a result of research, it was found that for indications identified, in order to use robots in STEAM class, for the students' intention to keep learning, it's essential for learners to have proper and active attitudes towards learning and basic knowledge of robots, and aspects of values should be considered that based on this, robot can assist in learning and affect results of learning in STEAM class. On the other hand, the factors of ease of learning and the combination of the challenge and technology do not gives direct (+) effect on the intention to continue learning and the value for learning, respectively. However, each of the two factor has indirect influence on each of the dependent variable within the significant range, which is the reason the author includes the result of the analysis.