• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.1
• /
• pp.1-9
• /
• 2010

This paper summarizes an education and training system for the auto-reclosing of power transmission system using a real time digital simulator. The system is developed to understand the principle of reclosing and the sequence of automatic reclosing schemes, and practice the effects of reclosing actions to power system in real-time simulator. This study is concentrated into the following two parts. One is the development of real time education and training system of automatic reclosing schemes. For this, we use the RTDS(real time digital simulator) and the actual digital protective relay. The mathematical relay model of RTDS and the actual distance relay which is equipped automatic reclosing function are also used. The other is the user friendly interface between trainee and trainer. The various interface displays are used for user handing and result display. The conditions of automatic reclosing which is a number of reclosing, reclosing dead time, reset time, and so on, can be changed by the user interface panel. A number of scenario cases are reserved for the education and training. Through the test, we verified that the proposed system can be effectively used to accomplish the education and training of automatic reclosing.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.510-512
• /
• 2005

This paper introduces the development of automatic system for estimation of digital relay performance. We have developed an automatic estimation system "HRV2004(Himap Relay function Verifier 2004)" for digital relay in 2004 and it has been verified in the field for one years. This paper describes the development details and field experience of HRV2004. HRV2004 can perform a series of jobs required for the relay testing in one environment and could handle most of all models of protective relay currently produced by Hyundai Heavy Industries. The functionality of this program consists of GUI of relay setting for beginner, fault record analysis and relay performance estimation. The core of this system is an automatic reporting of estimation test. If user is only click a button for relay estimation and one will received testing report to deliver customer. Additional benefit is fast response than the manual estimation. For example, the manual estimation takes spending 6 hours but this system is about 15 minutes.

• Journal of Families and Better Life
• /
• v.24 no.4 s.82
• /
• pp.117-126
• /
• 2006

This study examined the relations of maternal parenting and children's self-esteem to peer victimization as well as the gender differences in peer victimization. A sample of 494 5th- and 6th-grade children in Pusan answered three kinds of questionnaires regarding maternal parenting, children's self-esteem, and peer victimization. Peer victimization consisted of two constructs, bullying and victimization by pun. Data were analyzed by independent samples t-test and correlations. Boys showed more overt bullying and victimization by peers than girls, but relational peer victimization didn't vary as a function of the gender. Overall, the more boys and girls perceived their mothers as rejective/restricted, protective, and physically abusive, the more they were bullied and victimized. Both boys and girls were bullied and victimized by their peers when they showed lower self-esteem. Especially self-esteem was more highly correlated with victimization by peers than bullying.

• Transactions of Materials Processing
• /
• v.8 no.3
• /
• pp.295-295
• /
• 1999

In the present study, the corrosion behavior of AZ91D as-cast alloy was investigated form the viewpoint of the distribution aspect of precipitate ($Mg_{17}Al_{12}$) and the variation of Al concentration in the Mg-rich matrix. The dendrite arm spacing (DAS) of an as-cast specimen was measured as a function of degree which describes the distribution aspect of the precipitate, and the salt spray test was conducted for various grain-sired specimens fur 20 days. The dendrite arm spacing increased as the grain size increased to about 150㎛, but a constant value is indicated when the grain size exceeds that range. Although the relationship between the corrosion rate and grain size is of a nonlinear type, the linear trend between the corrosion rate and the dendrite arm spacing is maintained for the overall range of dendrite arm spacing. Since the precipitate in the as-cast alloy is discontinuously distributed, this linear relationship means that the variation of Al-solute concentration in the Mg-rich matrix has a more potent effect than the protective action of the precipitate on the corrosion behavior of an as-cast alloy.

• Physical Therapy Rehabilitation Science
• /
• v.4 no.1
• /
• pp.17-21
• /
• 2015

Objective: In this study, we aimed to test the hypothesis that aerobic exercise might exert its cardio-protective effect by preventing oxidative stress and improving cardiac function in rat models with doxorubicin-induced cardiomyopathy. Design: Randomized controlled trial. Methods: We randomly divided experimental rats into four groups: the normal group was used as a non-cardiomyopathy normal control (n=10); the control group included non-aerobic exercise after doxorubicin-induced cardiomyopathy (n=10); the experimental group I included aerobic exercise (3 m/min) after doxorubicin-induced cardiomyopathy (n=10); and experimental group II included aerobic exercise (8 m/min) after doxorubicin-induced cardiomyopathy. Rats in the treadmill training groups underwent treadmill training, which began at 2 weeks after the first intraperitoneal injection. At the end of the exercise period, we determined the heart weight change for each rat. Changes in the levels of oxidative stress enzymes (superoxide dismutase [SOD], thiobarbituric acid-reactive substances [TBARS], and catalase) in the cardiac tissue of rats from all four groups were examined at the end of the experiment. Results: Significant cardiac myocyte injury and increase in myocardial TBARS concomitant with a reduction in myocardial SOD and catalase were observed following cardiomyopathy (p<0.05). Significant cardiac tissue and increase in myocardial TBARS along with reduction in myocardial SOD and catalase were observed following cardiomyopathy (p<0.05). Oxidative parameters were significantly improved in the aerobic exercise groups compared with the control group. Conclusions: These findings indicate that aerobic exercise effectively prevents oxidative stress in rat models with cardiomyopathy.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.5
• /
• pp.731-738
• /
• 2016

Glucagon-like peptide-2 (GLP-2) is important for intestinal barrier function and regulation of tight junction (TJ) proteins, but the intracellular mechanisms of action remain undefined. The purpose of this research was to determine the protective effect of GLP-2 mediated TJ and transepithelial electrical resistance (TER) in lipopolysaccharide (LPS) stressed IPEC-J2 cells and to test the hypothesis that GLP-2 regulate TJ and TER through the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt)-mammalian target of rapamycin (mTOR) signaling pathway in IPEC-J2 cells. Wortmannin and LY294002 are specific inhibitors of PI3K. The results showed that $100{\mu}g/mL$ LPS stress decreased TER and TJ proteins occludin, claudin-1 and zonula occludens protein 1 (ZO-1) mRNA, proteins expressions (p<0.01) respectively. GLP-2 (100 nmol/L) promote TER and TJ proteins occludin, claudin-1, and zo-1 mRNA, proteins expressions in LPS stressed and normal IPEC-J2 cells (p<0.01) respectively. In normal cells, both wortmannin and LY294002, PI3K inhibitors, prevented the mRNA and protein expressions of Akt and mTOR increase induced by GLP-2 (p<0.01) following with the significant decreasing of occludin, claudin-1, ZO-1 mRNA and proteins expressions and TER (p<0.01). In conclusion, these results indicated that GLP-2 can promote TJ's expression and TER in LPS stressed and normal IPEC-J2 cells and GLP-2 could regulate TJ and TER through the PI3K/Akt/mTOR pathway.

• Journal of Yeungnam Medical Science
• /
• v.33 no.2
• /
• pp.85-89
• /
• 2016

Background: Formaldehyde is used to preserve cadaver in medical schools, and students are exposed to formaldehyde during cadaver dissection classes. When humans are exposed to formaldehyde, it induces mucosal inflammation, skin inflammation, and declining of neurobehavioral function including attention and memory executive functions. The purpose of this study is to identify the effects of formaldehyde exposure on student's neurobehavioral performance during cadaver dissection classes. Methods: The level of formaldehyde was measured in a cadaver dissection class. A total of 16 students were randomly divided into two groups. One group wore respiratory protection masks, while the other group did not. Among many subtests in Korean Computerized Neurobehavioral test, backward digit span was tested on all subjects before and after the class. Results: The length of memorized digit span between the two groups was not significant; however there was a greater decrease in neurobehavioral function after formaldehyde exposure in the non-mask group than the mask group. Conclusion: Formaldehyde exposure during cadaver dissection may likely decrease neurobehavioral performance of students. Therefore, proper ventilation system and respiratory protective equipment are necessary to protect medical school students from adverse effects of formaldehyde exposure.

• Natural Product Sciences
• /
• v.26 no.3
• /
• pp.252-258
• /
• 2020

This study investigated the biochemical and histological changes associated with the co-administration of cisplatin and methanolic extract of Portulaca oleracea (MEPO) in adult Wistar rats. Twenty-four (24) adult female Wistar rats were randomly divided into six (6) groups (A-F) (n = 4). Group A served as the control group for the experiment and received no treatment. Group B was given a single dose of cisplatin and served as the cisplatin control group. Group C and D received 400 mg/kg and 800 mg/kg of MEPO 6 hours after a single dose cisplatin injection respectively. Group E and F received 400 mg/kg and 800 mg/kg of MEPO 6 hours before cisplatin injection. The cisplatin injection was 2 mL/kg given intraperitoneally for all groups. There was a significant increase in the serum levels of ALT, ALP, AST, total bilirubin, and conjugated bilirubin following cisplatin treatment (p = 0.000, 0.000, 0.039, 0.000, 0.004 respectively) with a consequent reversal due to MEPO administration across all treated groups (p = 0.000, 0.000, 0.000, and 0.000) in a dose-dependent fashion. Cisplatin caused the expansion of the red and white pulp in the spleen which was attenuated by MEPO. MEPO demonstrated a protective effect against cisplatin-induced liver and spleen toxicity.

• Experimental and Molecular Medicine
• /
• v.50 no.11
• /
• pp.9.1-9.10
• /
• 2018

Although the positive effects of recombinant fibroblast growth factor-2 (rFGF-2) in chronic obstructive pulmonary disease (COPD) have been implicated in previous studies, knowledge of its role in COPD remains limited. The mechanism of FGF2 in a COPD mouse model and the therapeutic potential of rFGF-2 were investigated in COPD. The mechanism and protective effects of rFGF-2 were evaluated in cigarette smoke-exposed or elastase-induced COPD animal models. Inflammation was assessed in alveolar cells and lung tissues from mice. FGF-2 was decreased in the lungs of cigarette smoke-exposed mice. Intranasal use of rFGF-2 significantly reduced macrophage-dominant inflammation and alveolar destruction in the lungs. In the elastase-induced emphysema model, rFGF-2 improved regeneration of the lungs. In humans, plasma FGF-2 was decreased significantly in COPD compared with normal subjects (10 subjects, P = 0.037). The safety and efficacy of inhaled rFGF-2 use was examined in COPD patients, along with changes in respiratory symptoms and pulmonary function. A 2-week treatment with inhaled rFGF-2 in COPD (n = 6) resulted in significantly improved respiratory symptoms compared with baseline levels (P < 0.05); however, the results were not significant compared with the placebo. The pulmonary function test results of COPD improved numerically compared with those in the placebo, but the difference was not statistically significant. No serious adverse events occurred during treatment with inhaled rFGF-2. The loss of FGF-2 production is an important mechanism in the development of COPD. Inhaling rFGF-2 may be a new therapeutic option for patients with COPD because rFGF-2 decreases inflammation in lungs exposed to cigarette smoke.

• Archives of Plastic Surgery
• /
• v.49 no.3
• /
• pp.462-470
• /
• 2022

Background Reactive oxygen species cause serious damage to the physiological function of tissues. Determination of total antioxidant capacity of skin tissue is one of the determinants of damaged tissue function. Mast cells (MCs) are one of the groups of cells that are invited to the site of injury. The healing process begins with the rapid release of various types of MCs' intermediate factors at the site of injury. Bone marrow mesenchymal stem cell (BMMSC) production and secretion have been shown to regenerate the skin. The aim of this research was to evaluate the wound-healing and antioxidant effects of BMMSCs per MCs. Methods Fifty-four albino Wistar male rats were divided into three groups: (1) nonsurgery, (2) surgery, and (3) surgery + BMMSCs. Groups 2 and 3 were operated with a 3 × 8 cm flap and in group 3, cell injections (7 × 10⁹ cell injection at the time of surgery) were performed. After days 4, 7, and 15, percentage of the surviving tissue, histological characteristics, superoxide dismutase (SOD) activity, and amount of malondialdehyde (MDA) were measured in the groups. For results, Graph Pad Prism 8 software was used, and data were analyzed and compared by analysis of variance and Tukey test. Results BMMSCs' application decreased the amount of MDA, increased SOD activity and survival rate of the flaps, and improved the histological characteristics. Conclusion This study revealed the protective effects BMMSCs alongside MCs against oxidative stress on the survival of the flaps. However, for clinical use, more research is needed to determine its benefits.