• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.98-105
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• 2005

The relative sensitivity of two freshwater non- biting midges, Chironomus yoshimatsui Martin and Sublette and C. riparius Meigan, was examined for lead, cadmium, and mercury in water- only exposures. Two endpoints were compared to assess toxicity 48 h and 96 h after exposure: Acute toxicity ($50\%$ lethal concentration: $LC_50$) and behavioral toxicity ($50\%$ effective concentration: $EC_{50}$). for the behavioral toxicity, reduction of swimming performance of two midge species in the treated conditions was compared to that in the untreated control. The sensitivities differed depending on the species and heavy metals, although some trends emerged. $LC_50$ values in C. yoshimatsui to cadmium and lead were always higher than those in C. riparius with increasing toxicity, regardless of the exposure times. The opposit was true for the mercury treatment. Similar trends were observed in the $EC_{50}$ values. The $EC_{50}$ values were always lower than the $LC_50$ values in all the treatment cases (midge species, heavy metals, and exposure times). These results indicate that the two midge species respond to the heavy metals differently: C. riparius is sensive to cadmium and lead and C. yoshimatsui to mercury. Behavioral toxicity such as swimming performance can be an effective endpoint for assessing heavy metal toxicity in water.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.416-421
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• 2013

The purpose of this study was to investigate the effects of pH, temperature, light, sugars, and organic acids on the stability of anthocyanin pigments extracted from aronia (Aroniamelanocarpa). Pigments from aronia were most stable at pH 3.0, with maximal absorbance at 514 nm. High temperatures and prolonged heating substantially reduced anthocyanin contents. Anthocyanin levels were as low as approximately 21.70 and 79.63% of normal levels after 300 min of heating at 30 and $100^{\circ}C$, respectively. All of the sugars tested decreased the abundance of aronia pigments, with the levels highest in the presence of maltose, and decreasing progressively in the presence of galactose, sucrose, glucose, and fructose. Among the organic acids tested, citric acid was the most effective in stabilizing the aronia pigment, followed by tartaric acid, malic acid, formic acid, and ascorbic acid. These results provide useful reference data for efforts to use pigments from aronia in processed foods or for developing natural food colorants.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.376-385
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• 2022

The embedded demountable shear connector was developed in preparation for replacement works due to deterioration and damage to the bridge panel of the PSC girder bridge which is a road infrastructure directly related to the safety and convenience of the people. The demountable shear connector minimizes crushing works in the demolition process of the panel, and it is easy to re-construct the shear connector for replacement work. The economic feasibility of the PSC girder bridge using the embedded demountable shear connector compared to the existing construction method was analyzed from the perspective of road users (people) by calculating and comparing the cost of road users caused by traffic blocking during each construction method.

• Reproductive and Developmental Biology
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• v.28 no.3
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• pp.173-179
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• 2004

This study was conducted to investigate the toxi-cological effects of different vitrification solution on development of immature porcine oocytes in vitro. Oocytes were exposed to EFS solution [40% ethylene glycol (EG) + 18% Ficoll + 0.3M sucrose], ES solution (5.5M EG + 1.0M sucrose) or GE solution [10% glycol (G) + 20% EG], and these oocytes were transferred to sucrose solution directly. Maturation rates were significantly (P<0.05) higher in the ES solution (44.5%) and control (57.6%) than in the EFS solution (38.8%) and GE solution (22.4%). No differences among three solution were found in fertilization rates. Cleavage rates was significantly (P<0.05) higher in the ES solution (47.1%) and control (65.9%) than in the EFS solution (21.9%) and GE solution (19.0%), but no difference among three solutions was found in the blastocyst formation rates. These results indicate that combination of EG and sucrose solutions had effects on development of immature porcine oocytes.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.181-190
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• 2011

This study was investigated to find out the change of reproductive and histological biomarkers of Ruditapes philippinarum exposed to nonylphenol (NP). Experimental period was 16 weeks. Experimental groups were composed of one control condition and three NP exposure conditions (0.05, 0.1, $0.2 mg\;NP\;L^{-1}$). Gonad index was higher in exposure group than control in female and higher in control than exposure group in male. Intersexuality in the NP exposure group was 14.56% with male exhibiting higher ratio than female. Histological analysis of organ system illustrated expansion of hemolymph sinus, loss of striated border of inner epidermis and degeneration of mucous cell in the mantle. In the gill partially disappearance of frontal and lateral cilia, degeneration of mucous cell were observed. Also, hyperplasia of epithelium and disappearance of striated border were observed in the foot. As the concentration of NP increased, the accumulation of lipofuscin increased in the digestive gland. The results of this study suggest that NP induces reduction of survival rate, histopathology and intersex of R. philippinarum. Furthermore, it is indentified that NP functions as an estrogenic effector on the reproduction of R. philippinarum.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.1
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• pp.34-40
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• 2004

Unerupted maxillary anterior teeth is not a common case, However it may present practitioners with management problem. The cause of impaction is considered to be multifactorial, and local cause is the most common. These impacted teeth require surgical intervention, removal, transplantation, or surgical exposure, with or without orthodontic traction to align the malpositioned tooth. The preferred option is surgical exposure and orthodontic correction. Surgical intervention and orthodontic correction should not be delayed to avoid unnecessary difficulties in aligning the tooth in the arch. Surgical exposure should be performed with the intent of providing sufficient attached gingiva rather than simply uncovering the crown, which results in only alveolar mucosal attachment. Attached gingiva is essential to secure the gingival tissues to the adjacent teeth at the dentogingival junction. Thus preventing loss of periodontal tissues as a result of the pull of the surrounding soft tissues and facial muscles. Labially impacted maxillary anterior teeth uncovered with an apically positioned flap technique have more un- esthetic sequelae than those uncovered with a closed-eruption technique. In the case of severly displaced impacted teeth, autotransplantation ensures preservation of the alveolar bone and will facilitate future placement of an osseointegrated implant once growth has ceased or if ankylosis/resorption of the transplant occurs.

• Journal of Aquaculture
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• v.20 no.4
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• pp.226-231
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• 2007

We investigated survival and osmolarity, oxygen consumption, amonia extetion and filtration rates associated with physiological responses of the tunicate Halocynthia roretzi salinity changes. Acclimation times for osmolatity in different salinities took $20{\sim}26$ hours in 60% SW (19.8 psu) and $20{\sim}25$ hours in 80% SW (26.4 psu), while their times took $7{\sim}8$ hours in 110% SW (36.3 psu). Accordingly, acclimation times for high salinities were faster than those for low salinities. Survival (%) was more than 80% at salinity over 26.4 psu, and 6 $days-LS_{50}$ was 25.4 psu. physiological responses such as oxygen consumption, amonia excretion and filtration rates of H. roretzi showed more clear reactions in the longer exposure period (four days after exposure) than that in the beginning of the exposure. To sum up the results, the tunicate might be stressed from the beginning of the exposure in low salinity.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.137-144
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• 2013

The use of fiber-reinforced polymer (FRP) reinforcing bars in concrete structures has been increased as an alternative of steel reinforcement which has shown greater vulnerability to corrosion problem. However, the long-term performance of concrete members with FRP reinforcement is still questioned in comparison to the used of steel reinforcement. This study presents the results of an experimental study on the long-term behaviors of GFRP (glass fiber reinforced polymer) bar reinforced concrete beams after exposed to accelerated aging in an environmental chamber with temperature of $46^{\circ}C$ ($115^{\circ}F$) and 80% of relative humidity up to 300 days. The objectives of this research was to compare strength degradation and change of ductility between GFRP reinforced concrete beams and steel reinforcement beams after accelerated aging. Two types (wrapped and sand-coated surface) of GFRP bars and steel were reinforced. in concrete beams. Test results show that the failure modes of GFRP bar reinforced concrete beams are very similar with traditional RC beams, and the change of load-carrying capacity of steel reinforcing concrete beam is greater than that of GFRP bar reinforcing concrete beam under the accelerated aging. Test result also shows that the use of GFRP reinforcing in concrete could be introduced more brittle failure than that of steel reinforcing for practical application. The deformability factor up to compression failures indicates no significant variation before and after exposure of accelerated aging.

• Journal of Aquaculture
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• v.17 no.4
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• pp.235-239
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• 2004

Experiments were carried out to examine the effects of the different levels of oxygen, ammonia and hydrogen sulfide on survival, specific growth rate (SGR) and feed conversion ratio (FCR) of juvenile shrimp, Fenneropenaeus chinensis. Survival of the shrimp exposed to the hypoxia with $\leq$2.5 mg/L dissolved oxygen for 24 days were significantly affected. SGR and FCR of the shrimp exposed to$\leq$3.0 mg/L dissolved oxygen were significantly reduced than those of shrimp reared at 6.8 mg/L dissolved oxygen concentration. Survival of the shrimp exposed to $\geq$2.0 mg/L of ammonia levels for 24 days was significantly affected. Moreover, compared to the control group significant decrease of SGR and FCR of the shrimp has been observed with $\geq$1.0 mg/L and $\geq$0.5 mg/L of ammonia concentrations. In case of hydrogen sulfide, $\geq$0.5 mg/L was the critical level showed its significant negative effect on survival rate of shrimp exposed for 24 days. While, the group exposed with $\geq$0.07 mg/L and $\geq$0.05 mg/L hydrogen sulfide levels had a lower SGR and FCR values than did the control group in the same stipulated time of exposure.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.4
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• pp.171-181
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• 2018

As the proportion of sports events in the sports industry grows, the official sponsor market for sports events is also increasing. But because official sponsors are limited and expensive, some companies approach sporting events by way of Ambush marketing. This study is to analyze the differences of media exposure between official sponsors and general companies of mega sport events. To accomplish the purpose of the study, we collected text articles and analyzed them from the period of 2016 Rio Olympics, one year before the Olympics and one year after the Olympics. Web crawling was performed using Python for the collection of articles. Morphological and frequency analysis was performed using the KoNLP package and the TM package of statistical program R. In addition, the opinions of the related experts group were gathered to classify the companies or organizations in the media as the Organizing Committees for the Olympic Games(OCOGs), official sponsor, and general companies. As a result of the analysis, 5,220 times appeared related to the OCOGs, 7,845 times appeared related to the official sponsor, and 7,028 times appeared related to general companies. There isn't much difference in the frequency of exposure between official sponsors and general companies. It implies that Ambush marketing is recognized as a strategic marketing technique. The International Olympic Committee(IOC) has to recognize these social phenomena and establish reasonable standards for the marketing activities of official sponsors and general companies. And this study will serve as a basis for fair sponsor activities or marketing activities of sports events.