• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.10
• /
• pp.6852-6859
• /
• 2015

The purpose of this study was to determine the growth characteristics and distribution pattern of a brackish water clam Corbicula japonica in Seomjin River. Field samples were taken from 14 stations with salinity gradients during spring. Salinity at the bottom layer ranged from 1.0 psu to 32.9 psu, with low salinities in the upper area of the river. In particular, salinity at St.11 was decreased drastically to be ca. 15.0 psu, indicating an intermediate salinity zone. The distribution pattern of C. japonica was related to the salinity gradient, with the highest densities of $2,102ind.m^{-2}$ at Station 13, followed by $1,507ind.m^{-2}$ at Station 11. Here, we focused on the growth characteristics of collected C. japonica collected at two stations with different salinity values. The relationship between shell length and total weight was highly correlated ($R^2=0.91$, P<0.001) at Station 13 compared to that at Station 11 ($R^2=0.72$, P<0.001). On the other hands, the degree of correlation between shell length and shell height (SH) or shell width (SW) at Station 11 (SH: $R^2=0.91$, P<0.001; SW: $R^2=0.69$, P<0.001) was higher than that at Station 13 (SH: $R^2=0.64$, P<0.001; SW: $R^2=0.48$, P<0.001). In addition, fatness index of C. japonica at Station 13 was significantly (P < 0.001) higher than that at St. 11 (t-test value=-22.8, p<0.001). This implies that C. japonica at Station 13 might have enhanced their somatic growth, whereas C. japonica at Station 11 might have this kind of defense mechanism their internal organization against the salinity stress. Ecologically, this kind of defense mechanism of C. japonica against salinity flucuation may play an important role in their survival strategy.

• Tunnel and Underground Space
• /
• v.30 no.4
• /
• pp.382-393
• /
• 2020

The engineered barrier system of high-level radioactive waste disposal must maintain its performance in the long term, because it must play a role in slowing the rate of leakage to the surrounding rock mass even if a radionuclide leak occurs from the canister. In particular, it is very important to clarify gas dilation flow phenomenon clearly, that occurs only in a medium containing a large amount of clay material such as a bentonite buffer, which can affect the long-term performance of the bentonite buffer. Accordingly, DECOVALEX-2019 Task A was conducted to identify the hydraulic-mechanical mechanism for the dilation flow, and to develop and verify a new numerical analysis technique for quantitative evaluation of gas migration phenomena. In this study, based on the conventional two-phase flow and mechanical behavior with effective stresses in the porous medium, the hydraulic-mechanical model was developed considering the concept of damage to simulate the formation of micro-cracks and expansion of the medium and the corresponding change in the hydraulic properties. Model verification and validation were conducted through comparison with the results of 1D and 3D gas injection tests. As a result of the numerical analysis, it was possible to model the sudden increase in pore water pressure, stress, gas inflow and outflow rate due to the dilation flow induced by gas pressure, however, the influence of the hydraulic-mechanical interaction was underestimated. Nevertheless, this study can provide a preliminary model for the dilation flow and a basis for developing an advanced model. It is believed that it can be used not only for analyzing data from laboratory and field tests, but also for long-term performance evaluation of the high-level radioactive waste disposal system.

• Journal of Christian Education in Korea
• /
• v.62
• /
• pp.313-334
• /
• 2020

As an element of education, the educational space cannot be separated from the purpose of education. The place of education is not only the passage to deliver actual curriculum, but also the purpose itself that can be accomplished through educational content. That is because the purpose of education cannot be achieved only with instructors, students, curriculum, and methods, but requires a change in the perception of the educational space that represents the goal and the place where it all can be implemented. Nevertheless, the problem that lies with educational space is easy to be overlooked and it has been rather considered as an issue related to the finances or scale of the church. The church educational space gives birth to faith and growth, where spiritual development and experience may occur. However, the reality follows the drawbacks of conventional school classroom arrangements and structures. In addition, even if the church educational space can be arranged according to the needs of its students, it cannot deviate much from the standard uniform format. In particular, the basic environment of church educational space is similar to that of standard school system in terms of arrangement of furniture such as chairs, desks, and its physical structure. As the school system was originally designed and tailored for the purpose of delivering knowledge and standardization, the space for church education must stay away from it. Humans are born and die in a space, where encounter with God also happens. Also, communication with God causes spacial conversion to humans, changing the place of their visitation. So the church educational space must be more meticulously designed and comprehensive than that of school which pursues physical, educational, psychological, social, and artistic purposes because the church educational space pursues the liturgical elements, as well. Therefore, the Christian learning environmental arrangements must seek liturgical elements, which is the major Christian value, by placing Christian artwork or symbols for church visitors. So in this research, I want to stress the role of Christian educational space for spiritual growth and pursue intrinsic and extrinsic changes in learning environment, leading to a greater awareness of the Christian educational space.

• Journal of Life Science
• /
• v.21 no.11
• /
• pp.1625-1630
• /
• 2011

Heme oxygenase-1 (HO-1) is a stress-responsive protein that is known to regulate cellular functions such as cell proliferation, inflammation, and apoptosis. In this study, we investigated the role of NADPH oxidase on the expression of HO-1 in human liver hepatoma cell line HepG2. Diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, markedly inhibited HO-1 expression and the nuclear translocation of transcription factor Nrf2 in cobalt protoporphyrin (CoPP) or hemin-treated HepG2 cells. Similarly, the knockdown of $p47^{phox}$, a cytosolic factor for NADPH oxidase activity, by siRNA inhibited the CoPP-induced expression of HO-1. In addition, GSHmee, an intracellular antioxidant, blocked the expression of HO-1 in CoPP-treated cells. Based on these results, we conclude that the blockage of NADPH oxidase with DPI or $p47^{phox}$ siRNA inhibits CoPP-induced HO-1 expression in HepG2 cells, and also suggest that the expression of HO-1 in CoPP-induced HepG2 cells is associated with increase of intracellular ROS by NADPH oxidase activity.

• Journal of Life Science
• /
• v.27 no.5
• /
• pp.517-523
• /
• 2017

This study was to investigate the role of antioxidants on the characteristics of arsenite-damaged boar semen. Collected sperm was diluted with semen extender, and $100{\mu}M$ arsenite was used for sperm damage. Then melatonin, silymarin, curcumin, and vitamin E were applied for 3, 6, and 9 hr in arsenite-treated boar sperm. Sperm characteristics were then analyzed for motility, plasma membrane integrity, mitochondrial activity, and lipid peroxidation. In the results, sperm motility (control, $77.3{\pm}1.8%$) was decreased by arsenite ($33.3{\pm}1.5%$), while the antioxidant treatment groups (100 nM melatonin, $55.8{\pm}3.4%$; $2{\mu}M$ silymarin, $48.8{pm}3.4%$; $10{\mu}M$ curcumin, $53.9{\pm}2.8%$; and $500{\mu}M$ vitamin E, $54.5{\pm}3.1%$) showed increases compared to the arsenite group (p<0.05). $100{\mu}M$ arsenite decreased the sperm plasma membrane integrity ($24.5{\pm}1.6%$) and mitochondrial activity ($58.2{\pm}2.6%$), and increased lipid peroxidation ($5.3{\pm}0.2%$) at 3 hr (p<0.05). However, arsenite-treated samples with 100 nM melatonin, $2{\mu}M$ silymarin, $10{\mu}M$ curcumin, and $500{\mu}M$ vitamin E increased the plasma membrane integrity and mitochondria activity, and decreased lipid peroxidation compared to the arsenite-treated samples. In summary, arsenite may induce sperm damage and oxidation stress, while antioxidants such as melatonin, silymarin, curcumin, and vitamin E are useful for maintaining sperm characteristics. Therefore, antioxidants can protect sperm against damage by arsenite in fresh boar semen.

• Tuberculosis and Respiratory Diseases
• /
• v.63 no.6
• /
• pp.497-506
• /
• 2007

Background: The present investigation was performed in rats and isolated human neutrophils in order to confirm the presumptive role of the positive feedback loop of cytosolic phospholipase $A_2$ ($cPLA_2$) activation by plateletactivating factor (PAF). Methods: The possible formation of the positive feedback loop of the $cPLA_2$ activation and neutrophilic respiratory burst was investigated in vivo and in vitro by measurement of the parameters denoting acute lung injury. In addition, morphological examinations and electron microscopic cytochemistry were performed for the detection of free radicals in the lung. Results: Five hours after intratracheal instillation of PAF ($5{\mu}g/rat$), the lung leak index, lung myeloperoxidase (MPO) activity, the number of neutrophils and the concentration of cytokine-induced neutrophil chemoattractant (CINC) in bronchoalveolar lavage fluid were increased by PAF as compared with those of control rats. The NBT assay and cytochrome-c reduction assay revealed an increased neutrophilic respiratory burst in isolated human neutrophils following exposure to PAF. Lung and neutrophilic $cPLA_2$ activity were increased following PAF exposure and exposure to hydrogen peroxide increased $cPLA_2$ activity in the lung. Histologically, inflammatory findings of the lung were observed after PAF treatment. Remarkably, as determined by $CeCl_3$ cytochemical electron microscopy, increased production of hydrogen peroxide was identified in the lung after PAF treatment. Conclusion: PAF mediates acute oxidative lung injury by the activation of $cPLA_2$, which may provoke the generation of free radicals in neutrophils.

• Education of Primary School Mathematics
• /
• v.10 no.1 s.19
• /
• pp.41-56
• /
• 2007

Related with the mathematics gifted children the situation of different case studies is the research which is limited in mathematics problem solving process of the most mathematics gifted children. The research which it sees hereupon observes from the scope which is wider the quality of the mathematics gifted children, before the hazard mathematics gifted children whom it sees enter into the mathematics gifted children education center unit life and life after studying living and dismissal of a class from the general school, namely for their general life it leads compared to attitude it observes the reporter it does a quality. For a what kind of interest in the mathematics gifted children, the research leads the family or general class, from the gifted children education center it has it considers encouragement, map and to give a help to good mathematics gifted children education activation, it does. It will reach and to respect with afterwards it set a same three research problem. First, before entering into the mathematics gifted children education center, are the mathematics gifted children what kind of quality? Second, Are the mathematics gifted children what kind of quality for general school hour? Third, Are the mathematics gifted children what kind of quality after dismissal of a class after hour? Being selected in the hazard gifted children education center which solves an up research problem, simple characteristic and approach ease characteristic, by the condition of the permission possibility back it selected 2 person gifted children school boxes which are coming and going. And, before entering into these mathematics gifted children education center, studying life from the general school, life after dismissal of a class it will extend at 1 years, various recording it will ask and it collected direct observation and interview it led against their quality it analyzed. It shared the result which it analyzes with emotional quality, studying conduct qualities, general qualities of the mathematics gifted children and qualities of mathematics gifted children parents. Studies level of the mathematics gifted children parents high facility when them are young from, the interest and helping out which it has were considerable, to advance with the direction where in order for always with great disaster them are proper the map it did. In general quality of the mathematics gifted children from young age the ability which finds a language and a possibility concept superiorly the ability which expresses the thought of oneself logically was superior, the competitive spirit was high, it liked it came reading, a leader role, to reveal a deepening school with the fact that it comes and goes. Also it will burn with their studying conduct quality and it will roll and it did deeply and it arranged knot eagerly, accomplishing which is superior from the field which is various it showed, the originality was superior, the subject attachment power was high quite, oneself it studies it has a devotion the possibility of knowing it was. And, the social characteristic of the friends and is good with their emotional quality and it does there is own reflection and an encouragement at any time and also a confidence, but just as good as the stress also it receives the possibility of knowing it was to him.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.3
• /
• pp.343-349
• /
• 2010

The liver is the major target of ethanol toxicity and oxidative stress plays a role in development of alcoholic liver disease. This study was performed to investigate the effects of green tea extracts (GTE) on acute ethanol-induced hepatotoxicity in rats. Experimental animals were divided into 4 groups, control, GTE, ethanol, and GTE+ethanol treatment, with 5 rats in each group. Ethanol (6 g/kg body weight (BW)) and GTE (200 mg/kg BW) were treated by gavage. At 1 hour, 3 hours and 20 days (6 g/kg BW every 2 days for total 10 doses) after ethanol and/or GTE treatments, animals were killed; hepatic tumor necrosis factor-alpha (TNF-$\alpha$) and glutathione level, serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), hepatic antioxidant enzymes (SOD, CAT, GPx) activities and hepatic thiobarbituric acid reactive substances (TBARS) were measured. At 1 hour and 3 hours, hepatic TNF-$\alpha$ levels were increased significantly in ethanol group and ethanol+GTE group but that levels was significantly lower in ethanol+GTE group compared with ethanol group. Hepatic glutathione level was decreased by ethanol treatment but GTE prevented the ethanol-induced glutathione decrement. The levels of liver marker enzymes (AST, ALT), liver antioxidant enzymes (SOD, CAT, GPx) and lipid peroxidation marker (TBARS) were not changed in rats of 1 and 3 hours after ethanol treatment. After 20 days, GTE decreased the changes of liver marker enzymes (AST, ALT) activities and TBARS level by ethanol. This study shows that GTE beneficially modulates TNF-$\alpha$ and glutathione levels in liver of ethanol administered rats. The GTE supplementation could be beneficial to liver by decreasing early changes of biomarkers of liver damage caused by ethanol.

• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.2
• /
• pp.182-206
• /
• 2003

Statement of problem : Successful osseointegration of endosseous threaded implants is dependent on many factors. These may include the surface characteristics and gross geometry of implants, the quality and quantity of bone where implants are placed, and the magnitude and direction of stress in functional occlusion. Therefore clinical quantitative measurement of primary stability at placement and functional state of implant may play a role in prediction of possible clinical symptoms and the renovation of implant geometry, types and surface characteristic according to each patients conditions. Ultimately, it may increase success rate of implants. Purpose : Many available non-invasive techniques used for the clinical measurement of implant stability and osseointegration include percussion, radiography, the $Periotest^{(R)}$, Dental Fine $Tester^{(R)}$ and so on. There is, however, relatively little research undertaken to standardize quantitative measurement of stability of implant and osseointegration due to the various clinical applications performed by each individual operator. Therefore, in order to develop non-invasive experimental method to measure stability of implant quantitatively, the resonance frequency analyzer to measure the natural frequency of specific substance was developed in the procedure of this study. Material & method : To test the stability of the resonance frequency analyzer developed in this study, following methods and materials were used : 1) In-vitro study: the implant was placed in both epoxy resin of which physical properties are similar to the bone stiffness of human and fresh cow rib bone specimen. Then the resonance frequency values of them were measured and analyzed. In an attempt to test the reliability of the data gathered with the resonance frequency analyzer, comparative analysis with the data from the Periotest was conducted. 2) In-vivo study: the implants were inserted into the tibiae of 10 New Zealand rabbits and the resonance frequency value of them with connected abutments at healing time are measured immediately after insertion and gauged every 4 weeks for 16 weeks. Results : Results from these studies were such as follows : The same length implants placed in Hot Melt showed the repetitive resonance frequency values. As the length of abutment increased, the resonance frequency value changed significantly (p<0.01). As the thickness of transducer increased in order of 0.5, 1.0 and 2.0 mm, the resonance frequency value significantly increased (p<0.05). The implants placed in PL-2 and epoxy resin with different exposure degree resulted in the increase of resonance frequency value as the exposure degree of implants and the length of abutment decreased. In comparative experiment based on physical properties, as the thickness of transducer increased, the resonance frequency value increased significantly(p<0.01). As the stiffness of substances where implants were placed increased, and the effective length of implants decreased, the resonance frequencies value increased significantly (p<0.05). In the experiment with cow rib bone specimen, the increase of the length of abutment resulted in significant difference between the results from resonance frequency analyzer and the $Periotest^{(R)}$. There was no difference with significant meaning in the comparison based on the direction of measurement between the resonance frequency value and the $Periotest^{(R)}$ value (p<0.05). In-vivo experiment resulted in repetitive patternes of resonance frequency. As the time elapsed, the resonance frequency value increased significantly with the exception of 4th and 8th week (p<0.05). Conclusion : The development of resonance frequency analyzer is an attempt to standardize the quantitative measurement of stability of implant and osseointegration and compensate for the reliability of data from other non-invasive measuring devices It is considered that further research is needed to improve the efficiency of clinical application of resonance frequency analyzer. In addition, further investigation is warranted on the standardized quantitative analysis of the stability of implant.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.11
• /
• pp.1673-1680
• /
• 2016

The purpose of this study was to examine how customer orientation (CO) reduces employee stress to customers (CSS). As emotional labor strategies [surface acting (SA) and deep acting (DA)] may mediate a role between CO and CSS, we verified multiple parallel mediator roles of SA and DA between CO and CSS. Our survey was administered to 323 school foodservice employees in Daegu and Gyeongbuk. The results show that CO increased DA but did not decrease SA, and SA had a positive effect on CSS while DA did not influence CSS. These results did not support the parallel multiple mediator model. We conducted post-hoc model modification and proposed the serial multiple mediator model as a modified model. As a result, CO increased DA, DA reduced SA, and SA showed a positive relation with CSS. This double mediating effect through DA and SA between CO and CSS was significant. Based on these results, we found that CO did not have a direct effect on SA and CSS. DA did not directly reduce CSS while CO reduced SA and CSS through DA indirectly. DA had a negative effect on CSS through SA indirectly. Finally, implications and limitations of this are discussed.