• Journal of Life Science
• /
• v.25 no.12
• /
• pp.1384-1392
• /
• 2015

Sagantang (SGT), a Korean multiherb formula comprising six medicinal herbs, Paeonia lactiflora Pall., Belamcanda chinensis (L.) DC, Gardenia jasminoides Ellis, Poria cocos Wolf, Cimicifuga heracleifolia Komarov, and Artractylodes japonica Koidzumi, was recorded in “Dongeuibogam.” The present study investigated the anticancer potential of SGT in AGS human gastric carcinoma cells. The results indicated that SGT treatment significantly inhibited the growth and viability of AGS cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies, in addition to chromatin condensation and DNA fragmentation, and the accumulation of annexin-V positive cells. The induction of apoptotic cell death by the SGT treatment was associated with up-regulation of Fas protein expression, truncation of Bid, and down-regulation of the anti-apoptotic Bcl-2 protein. The SGT treatment also effectively induced the loss of mitochondrial membrane potential, which was associated with the activation of caspases (caspase-3, -8, and -9) and degradation of poly (ADP-ribose) polymerase. However, a pan-caspase inhibitor significantly blocked the SGT-induced apoptosis and growth suppression in AGS cells. This study suggests that SGT induces caspase-dependent apoptosis through an extrinsic pathway by upregulating Fas, as well as through an intrinsic pathway by modulating Bcl-2 family members in AGS cells. The results suggest that SGT may be a potential chemotherapeutic agent for the control of human gastric cancer cells. However, further studies will be needed to confirm the potential of SGT in cancer prevention and therapy in an in vivo model and to identify biological active compounds of SGT.

• Applied Microscopy
• /
• v.40 no.2
• /
• pp.73-80
• /
• 2010

Liver regeneration is a result of highly coordinated proliferation of hepatocytes and nonparenchymal liver cells. Partial hepatectomy (PH) is the most often used stimulus to study liver regeneration because, compared with other methods that use hepatic toxins, it is not associated with the tissue injury and inflammation, and the initiation of the regenerative stimulus is precisely defined. Granulocyte macrophage-colony stimulating factor (GM-CSF), which is a cytokine able to regulate the proliferation and differentiation of epithelial cells, was first identified as the most potent mitogen for bone marrow. Particularly, rrhGM-CSF, which is highly glycosylated and sustained longer than any other types of GM-CSF in the blood circulation, was specifically produced from rice cell culture. In this experiment, effects of rrhGM-CSF administration were evaluated in the regenerating liver after 78% PH of rats. Morphological changes induced by PH were characterized by destroyed hepatocyte plate around the central vein and enlarged nuclear cytoplasmic ratio and increased hepatocytes with two nuclei. And then, proliferation of liver cells (parenchymal and nonparenchymal) and rearrangement of plates and lobules seemed to be carried out during liver regeneration. These alterations in the experimental group preceded those of the control. Since proliferating cell nuclear antigen (PCNA) is known to be a nuclear protein maximally elevated in the S phase of proliferating cells, the protein was used as a marker of liver regeneration after PH in rats. PCNA levels by western blot analysis and immunohistology were compared between the two groups. PCNA protein expression of two groups at 12 hr and 24 hr after injury showed similar pattern. The protein expression showed the peak at 3 days in both groups, however, the protein level of the experimental group was higher than that of the control. On immunohistochemical observations, the reaction product of PCNA was localized at the nuclei of proliferating cells and the positive reaction in experimental group at 3 days was clearly stronger than that in control group. The results by Western blotting and immunohistology for PCNA showed similar pattern in terms of the protein levels. In conclusion, rrhGM-CSF administration during liver regeneration after 78% PH accelerated breakdown and restoration of the hepatic plate and expression of PCNA. These results suggest that rrhGM-CSF might play an important role during liver regeneration in rats.

• Journal of Gifted/Talented Education
• /
• v.22 no.3
• /
• pp.575-596
• /
• 2012

Students' perception on a science program for gifted was investigated. The whole program was designed in consistency and integrity based on the Autonomous Learner Model suggested by Betts & Kercher(1999). 7th, 8th and 9th grade students were enrolled in this program, offered by G Education Institute for Gifted(GEI) located in Seoul. A survey was done to ask students' perception regarding the effect of the program. The survey consisted of statements about the expected effects of the program and students were asked if they agreed with the statements. Most students strongly agreed that GEI's program has positive effects. Students replied that they learned useful and interesting science contents, enjoyed meaningful experience of cooperating with members in small groups, and were challenged by the inquiry tasks. They recognized that they were being trained to become autonomous learners. They also said that their choices and decisions were respected, which resulted in positive effects on their ability to negotiate or to inquire actively. These implies that Autonomous Learner Model had been successfully applied. Although it was not clear autonomy of students was fully grown, the possibility of becoming an autonomous learner was evident. Satisfaction level is higher for the older students, implying that the integrity in the program gave accumulating effect. Students response showed that three sub-programs of GEI, the classes of each subject, conference at the end of the year and autonomous learner training played equally important role for students to learn the process of scientific inquiry and autonomous learning. This was a positive sign that the strategies for scientific inquiry and autonomous learning were embedded and integrated deeply in the program. The results of current research suggests that the integrity of a program based on a specific education model for the gifted could provide better education environment for the gifted students.

• Korean journal of communication and information
• /
• v.33
• /
• pp.115-167
• /
• 2006

The purpose of this study was to investigate coverage patterns of the Korean internet news media on 'US-Iraq War' and its meaning and discourse structure. The internet news media was recently established and become a popular news media to compete with old news media in Korea. The author selected the 'Oh My News' as a representative internet news media for his analysis, and collected its news items from Mar. 20, 2003 to Dec. 17, 2003. on the basis of 4 different phases of the war. He analysed the whole of news items with various semiotic and discourse analytic methods, especially applying for Bell's concepts of time and discourse structure. As a result of this study, first of all, it was found that the 'Oh My News' tended to cover this war so different ways as the old news media did. It did not pay attention to the procedure of war, especially, battlefields, fighting between US and Iraq, damages and casualties. But, instead, it paid attention to many doubts about intention of US government and the President, Bush, dichotomous shift between pro-America and anti-America, rightness of dispatching Korean army into Iraq, etc. Secondly, it functioned as a kind of alternative media to speak up different voices comparing with those of old media. It tended to suggest different perspectives and opinions, while the old media tended to follow American perspectives and opinions. Thirdly, it became as a kind of new media setting agendas for this war in Korean society. It played a very important role for setting agendas for various issues related with this war. In conclusion, the internet news media has recently become a kind of new news media for suggesting alternative or different opinions, setting agendas, initiating discourses, etc., even though it still has may problems of becoming so called orthodox news media.

• The Journal of Society for e-Business Studies
• /
• v.21 no.3
• /
• pp.51-78
• /
• 2016

Online-to-offline (O2O) commerce is the new trend that merges online commerce with traditional industries in various fields. The primary purpose of this paper is to find out which factors influence customers' intention to switch from call-based driver-for-hire services to O2O app-based services. This study used variables and factors based on Theory of Switching Intention, and Extended Unified Theory of Acceptance and Use of Technology in order to design research questions. We surveyed 500 users of call-based driver-for-hire services. According to the result of this study, dissatisfaction with the current call-based driver-for-hire services is estimated to be a significant factor that strengthens customers' intention to switch from the call-based driver-for-hire services to the app-based services. Loyalty to the previous call-based driver-for-hire services was not seen as a crucial motivator that causes customers to switch to the new O2O driver service. Switching cost also did not play a key role in explaining the relationship between dissatisfaction with the current call-based service and the intention to use the new app-based service. Performance expectancy, easiness in use, the level of user's knowledge or available assistance in relation to the use of app-based services, and expectancy for reasonable price was found to have meaningful impacts on customers' intention to switch from the call-based driver-for-hire services to the app-based services. Age, gender and user experience on the new service were found incapable of moderating the relationship between aforementioned factors which influence customers' choice of the app-based driver-for-hire service, and customers' intent to switch to the app-based service.

• Journal of Veterinary Clinics
• /
• v.27 no.5
• /
• pp.553-558
• /
• 2010

The purpose of this study was to investigate the effects of premedicated ascorbic acid and hepa-saline irrigation/aspiration on attenuation of ischemia-reperfusion (I/R) injury and recovery of renal function in canine nephrotomy model. In the canine model, nine mixed dogs were subjected to renal nephrotomy with premedicated ascorbic acid and hepa-saline irrigation-aspiration (treatment group 2), and only hepa-saline irrigation-aspiration (treatment group 1). The level of renal function and antioxidant enzymes after nephrotomy were measured. And the expression pattern of TNF-${\alpha}$ and INF-${\gamma}$ was examined in the renal tissue at $7^{th}$ day after nephrotomy. BUN and creatinine levels significantly decreased in the treatment group 1 and 2 compared to that of control group at the $3^{rd}$, 5th and $7^{th}$ day after reperfusion (p < 0.05). And, there was significant difference between treatment group 1 and 2 at the $3^{rd}$ day after reperfusion (p < 0.05). The activities of antioxidant enzymes in plasma was significantly increased in the treatment group 1 and 2 compared to that of control group at the $3^{rd}$, $5^{th}$ and $7^{th}$ day after reperfusion (p < 0.05). And, there was significant difference between treatment group 1 and 2 at the $3^{rd}$ day after reperfusion (p < 0.05). TNF-${\alpha}$ was decreased and INF-${\gamma}$ was increased in treatment groups. The result of this study suggested that irrigation-aspiration has effects on attenuation of renal ischemia-reperfusion injury, and the exogenous ascorbic acid has a role in the attenuation of renal ischemia-reperfusion injury and recovery of renal function in canine nephrotomy model.

• Journal of the Korean Home Economics Association
• /
• v.37 no.5
• /
• pp.61-84
• /
• 1999

The purpose of this study is to understand the context of cosumers' lives in Korea with a narrative analysis method. The epistemological orientation of eh narrative analysis is Interpretivism, which blends the two polar philosophical perspectives, Empiricism and Rationalism, and includes Narrotology, Hermeneneutics, Semiotics, and Structural Criticism. Narrative analysis takes as its object of investigation the story itself. This study collects eleven narrative plots from four housewives, into which Labov's structural approach is applied. This study shows clearly that the socio-cultural environment in which consumers live has strong influence on their consumption behavior and also reveals that narrativization tells not only about past actions but how individuals understand those actions, that is, meaning.

• Restorative Dentistry and Endodontics
• /
• v.34 no.3
• /
• pp.169-176
• /
• 2009

Diabetes Mellitus (DM) is a syndrome accompanied with the abnormal secretion or function of insulin, a hormone that plays a vital role in controlling the blood glucose level (BGL). Type land 2 DM are most common form and the prevalence of the latter is recently increasing, The aim of this article was to assess whet her Type 2 DM could act as a predisposing risk factor on the pulpo-periapical pathogenesis. Previous literature on the pathologic changes of blood vessels in DM was thoroughly reviewed. Furthermore, a histopathologic analysis of artificially-induced periapical specimens obtained from Type 2 diabetic and DM-resistant rats was compared. Histopathologic results demonstrate that the size of periapical bone destruction w as larger and the degree of pulpal inflammation was more severe in diabetic rats, indicating that Type 2 D M itself can be a predisposing risk factor that makes the host more susceptible to pulpal infection. The possible reasons may be that in diabetic state the lumen of pulpal blood vessels are thickened by atheromatous deposits, and microcirculation is hindered, The function of polymorphonuclear leukocyte is also impair ed and the migration of immune cells is blocked, leading to increased chance of pulpal infection. Also, lack of collateral circulation of pulpal blood vessels makes the pulp more susceptible to infection. These decrease the regeneration capacity of pulpal cells or tissues, delaying the healing process, Therefore, when restorative treatment is needed in Type 2 DM patients, dentists should minimize irritation to the pulpal tissue un der control of BGL.

• Journal for History of Mathematics
• /
• v.22 no.2
• /
• pp.27-52
• /
• 2009

This article discusses the contributions of the leader Oswald Veblen, who was the president of AMS during 1923-1924. In 2006, Korea ranked 12th in SCIE publications in mathematics, more than doubling its publications in less than 10 years, a successful model for a country with relatively short history of modern mathematical research. Now there are 192 four-year universities in Korea. Some 42 of these universities have Ph.D. granting graduate programs in mathematics and/or mathematical education in Korea. Rapid growth is observed over a broad spectrum including a phenomenal performance surge in International Mathematical Olympiad. Western mathematics was first introduced in Korea in the 17th century, but real significant mathematical contributions by Korean mathematicians in modern mathematics were not much known yet to the world. Surprisingly there is no Korean mathematician who could be found in MaC Tutor History Birthplace Map. We are at the time, to have a clear vision and leadership for the 21st century. Even with the above achievement, Korean mathematical community has had obstacles in funding. Many people thinks that mathematical research can be done without funding rather unlike other science subjects, even though they agree fundamental mathematical research is very important. We found that the experience of early American mathematical community can help us to give a vision and role model for Korean mathematical community. When we read the AMS Notice article 'The Vision, Insight, and Influence of Oswald Veblen' by Steve Batterson, it answers many of our questions on the development of American mathematics in early 20th century. We would like to share the story and analyze its meaning for the development of Korean Mathematics of 21st century.

• Korean Journal of Mineralogy and Petrology
• /
• v.34 no.3
• /
• pp.157-167
• /
• 2021

Lead (Pb) is one of the key trace elements, exhibiting a peculiar partitioning behavior into silicate melts in contact with minerals. Partitioning behaviors of Pb between silicate mineral and melt have been known to depend on melt composition and thus, the atomic structures of corresponding silicate liquids. Despite the importance, detailed structural studies of Pb-bearing silicate melts are still lacking due to experimental difficulties. Here, we explored the effect of lead content on the atomic structures, particularly the evolution of silicate networks in Pb-bearing sodium metasilicate ([(PbO)_x(Na₂O)_1-x]·SiO₂) glasses as a model system for trace metal bearing natural silicate melts, using ²⁹Si solid-state nuclear magnetic resonance (NMR) spectroscopy. As the PbO content increases, the ²⁹Si peak widths increase, and the maximum peak positions shift from -76.2, -77.8, -80.3, -81.5, -84.6, to -87.7 ppm with increasing PbO contents of 0, 0.25, 0.5, 0.67, 0.86, and 1, respectively. The ²⁹Si MAS NMR spectra for the glasses were simulated with Gaussian functions for Qⁿ species (SiO₄ tetrahedra with n BOs) for providing quantitative resolution. The simulation results reveal the evolution of each Qⁿ species with varying PbO content. Na-endmember Na₂SiO₃ glass consists of predominant Q² species together with equal proportions of Q¹ and Q³. As Pb replaces Na, the fraction of Q² species tends to decrease, while those for Q¹ and Q³ species increase indicating an increase in disproportionation among Qⁿ species. Simulation results on the ²⁹Si NMR spectrum showed increases in structural disorder and chemical disorder as evidenced by an increase in disproportionation factor with an increase in average cation field strengths of the network modifying cations. Changes in the topological and configurational disorder of the model silicate melt by Pb imply an intrinsic origin of macroscopic properties such as element partitioning behavior.