• Journal of Korean Neurosurgical Society
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• 제59권3호
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• pp.259-268
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• 2016

Objective : Accumulation of advanced glycation end-products (AGE) and mitochondrial glycation is importantly implicated in the pathological changes of the brain associated with diabetic complications, Alzheimer disease, and aging. The present study was undertaken to determine whether sildenafil, a type 5 phosphodiesterase type (PDE-5) inhibitor, has beneficial effect on neuronal cells challenged with AGE-induced oxidative stress to preserve their mitochondrial functional integrity. Methods : HT-22 hippocampal neuronal cells were exposed to AGE and changes in the mitochondrial functional parameters were determined. Pretreatment of cells with sildenafil effectively ameliorated these AGE-induced deterioration of mitochondrial functional integrity. Results : AGE-treated cells lost their mitochondrial functional integrity which was estimated by their MTT reduction ability and intracellular ATP concentration. These cells exhibited stimulated generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential, induction of mitochondrial permeability transition, and release of the cytochrome C, activation of the caspase-3 accompanied by apoptosis. Western blot analyses and qRT-PCR demonstrated that sildenafil increased the expression level of the heme oxygenase-1 (HO-1). CoPP and bilirubin, an inducer of HO-1 and a metabolic product of HO-1, respectively, provided a similar protective effects. On the contrary, the HO-1 inhibitor ZnPP IX blocked the effect of sildenafil. Transfection with HO-1 siRNA significantly reduced the protective effect of sildenafil on the loss of MTT reduction ability and MPT induction in AGE-treated cells. Conclusion : Taken together, our results suggested that sildenafil provides beneficial effect to protect the HT-22 hippocampal neuronal cells against AGE-induced deterioration of mitochondrial integrity, and upregulation of HO-1 is involved in the underlying mechanism.

• 동의생리병리학회지
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• 제26권3호
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• pp.273-280
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• 2012

Scutellaria baicalensis Georgi, which has been known to be able to clear away heat and remove dampness, was used for febrile disease. It is now clear that Advanced glycation end products (AGEs) play major roles in the pathogenesis of diabetic complications such as atherosclerosis. In this study, we examined whether Scutellaria baicalensis Georgi suppress the AGE mediated inflammatory responses in the THP-1 cells. AGE treatment increased the gene expression of pro-inflammatory cytokines such as tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-$1{\beta}$ (IL-$1{\beta}$), monocyte chemotactic protein-1 (MCP-1) and cyclooxygenase-2 (COX-2). Reverse transcriptase-polymerase chain reaction and Western blot analysis revealed that S. baicalensis had inhibitory effects on the expression of pro-inflammatory genes and protein levels in AGE-treated THP-1 cells. S. baicalensis had also reduced the production of ROS in the AGE-treated THP-1 cells. These results suggest that S. baicalensis has inhibitory effects for the development of diabetic vascular complication.

• 생약학회지
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• 제43권4호
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• pp.338-344
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• 2012

Advanced glycation end products (AGEs) have been postulated to play a central role in the development of diabetic complications. A variety of different agents that inhibit AGEs have been under investigation. In this study, 62 herbal medicines from China and Vietnam have been investigated with an in vitro evaluation system using AGEs formation inhibitory activity. Of these, 5 herbal medicines ($IC_{50}$ < $5{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Particularly, herbal medicines Albizia odoratissima (twigs and leaves), Rhododendron spinuliferum (twigs and leaves), Dioscorea cirrhosa (stems and leaves), Illicium verum (stems and leaves) and Aglaia perviridis (stems and leaves), showed more potent inhibitory activity (approximately 16-26 fold) than the positive control aminoguanidine ($IC_{50}=76.47{\mu}g/ml$).

• 수산경영론집
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• 제24권2호
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• pp.1-16
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• 1993

Because of the radical changes in the domestic and foreign economic circumstances Koreaa fisheries is confronted with difficulties. Along the end of the UR marine products of other nations are rushing into Korea. Also migration of labor to other industries and rise of wage level in Korean fisheries deteriorate managerial conditions. But in Korea which has little natural resourses fisheries is still more important. That is \circled1 creating job opportunites \circled2 increase of income \circled3 supply of foodstuffs and animal protein \circled4 acquisition of foreign currency \circled5 enlargement of domestic market for industrial products \circled6 development of other interrelated industries \circled7 rational use of domestic resourses \circled8 diversification of population and production activites \circled9 contribution to balanced growth of national economy by the developing regional economy. These roles of fisheries in national economy mentioned above are to be excuted forward. In spite of the radical change in the economic circumstances at the end of the UR fisheries if crucial in Korea as a industry. For this our fisheries is to be made to compete with foreign fisheries. Through the cheap price and high quality our fisheries must be came to compete with foreign fisheries and meet the people's needs for marine products. For this it is necessary to maintain high productivity and competitive power. Now with the exception of a portion of the deep - sea fishing, our fisheries is generally paltry, Especially inshore fishery which is the main stock in our fisheries is very paltry and so productivity and competetive power are very low. So to develop our fisheries which has s comparative disadvantage active polices that follows below are to be promoted on a large scale. \circled1 improvement of structure \circled2 augmentation of productivity in fishing ground by making fisheries resourses \circled3 enlargement of finantial and monetary assistance \circled4 effective administration of fisheries cooperative union \circled5 activation of R&D etc These polices which need to be scientific and comprehensive are very valuable. Especially without making fishieries resources we cannot expect economy of scale, promotion of productivity and development of fisheries. And we do also endeavour to gather the results of the study and investigation about fisheries domestic and foreign and do ceaselessly put these to practical use systimatically.

• 한국의류학회지
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• 제18권5호
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• pp.749-764
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• 1994

It was assumed that a consumer forms images of all the factors related to clothing merchandise such as trademarks, stores, products and prices that he/she perceives in the market and those images deforming his/her preference for a particular piece of clothes and intention of purchase. Under this assumption, this research was designed to find out important factors of clothes that help a consumer form an image of the clothes, among other attributes of the merchandise, and how this image is related to the existing extraneous variables such as the trademark image, the consumer's self image, the price, etc. in leading the consumer to purchase the particular clothes in the end. In the empirical research, a preliminary survey was conducted to select brands of womenswear that were suitable for this study and as the result, 16 brands were chosen. Then one trademark, one store and two products from each of the 16 brands were selected. With these materials, 32 stimulus sheets were prepared, and each of them was composed of 3 photos of a brand's catalog and logo, the interior of a selected store that carried products of the brand, and formal suits selected from each brand's spring/summer 1993 collections. Subjects were 460 women in the age groups of 20-50s who live in Seoul Metropolitan area. Each of the subjects was provided with a survey questionnaire and 16 stimulus sheets. The main findings of this research prove that consumers follow a certain selection process model when they purchase clothes: consumers, first, from images of merchandise based on the trademarks, stares, and products and those formed images work il.: medium variables and in the end they help the consumers decide whether to buy the products.

• 펄프종이기술
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• 제42권3호
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• pp.7-13
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• 2010

KOptimization and control of wet-end process provide a key solution to improve paper quality and production efficiency at the same time. Wet-end of paper machine is to determine three important influencing factors of papermaking i.e., retention, drainage and formation. Good formation of paper could be made at the cost of deteriorated retention or drainage. In the same manner increase of retention aid could cause the bad formation of paper. It is very important to find a proper retention chemical which may satisfy one of three factors without the sacrifice of other two. Laboratory scale analyzing or screening chemical additives of wet-end was reported in this study based on RDA sheet molding. Different from the conventional test method, simultaneous consideration of three important wet-end properties could be made by RDA and consequently more reliable prediction of actual paper machine wet-end could be expected.

• 산업경영시스템학회지
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• 제42권2호
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• pp.1-8
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• 2019

Network externalities are essentially dynamic in that the value consumers feel about a product is affected by the size of the existing customer base that uses that product. However, existing studies on network externalities analyzed the effects of network externalities in a static way, not dynamic. In this study, unlike previous studies, the impact of network externalities on price competition in a vertically differentiated market is dynamically analyzed. To this end, a two-period duopoly game model was used to reflect the dynamic aspects of network externalities. Based on the game model, the Nash equilibria for price, sales volume, and revenue were derived and numerically analyzed. The results can be summarized as follows. First, if high-end product has strong market power, the high-end product vendor takes almost all benefits of the network externality. Second, when high-end product has strong market power, the low-end product will take over most of the initial sales volume increase. Third, when market power of high-end product is not strong, it can be seen that the effects of network externalities on the high and low-end products are generally proportional to the difference in quality. Lastly, if there exists a strong network externality, it is shown that the presence of low-end product can be more profitable for high-end product vendor. In other words, high-end product vendor has incentive to disclose some technologies for the market entrance of low-end product, even if it has exclusive rights to the technologies. In that case, however, it is shown that the difference in quality should be maintained significantly.

• 지식경영연구
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• 제16권4호
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• pp.109-132
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• 2015

We examine offline and online channel sales of experience goods, and compare and contrast the sales patterns of existing products and new products between channels. To this end, we obtain the channel-specific time-series sales data from the leading company selling beauty products, both offline and online. By applying the Vector Autoregressive Model, we empirically find out how the relationship between existing products and new products changes between the shopping channels. Our empirical findings are as follows. First, the sales effects from existing products to new products are significantly positive at both offline and online channels, and this positive effect is greater in the offline channel than in the online channel. Second, the influence of new products on existing products is more positive in the offline channel than in the online channel. Third, the impact of existing products sales on new products sales is greater than that of new products on existing products. Lastly, the inertia effect, the effect within the same shopping channel and the same selling product, is significantly positive in the offline channel but not in the online channel, and this asymmetric inertia effect emerges as we focus on experience goods. Moreover, the impulse response function analysis provides the three important implications. First, companies should pay attention to the same channel but different types of products. Second, the offline channel is more vulnerable to market shock than the online channel. Third, new products sales vary by existing products sales to the greater extent, compared to the opposite relationship. We believe our study contributes theoretically and practically to the fields of marketing and knowledge management.

• 대한수학회보
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• 제53권3호
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• pp.751-763
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• 2016

The properties of the nonabelian tensor products are interesting in different contexts of algebraic topology and group theory. We prove two theorems, dealing with the nonabelian tensor products of projective limits of finite groups. The first describes their topology. Then we show a result of embedding in the second homology group of a pro-p-group, via the notion of complete exterior centralizer. We end with some open questions, originating from these two results.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.141-141
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• 2006

Petrochemicals contain a wide variety of monomers and their derivatives which are used in the production of plastics, fibers and synthetic rubber. Until now, petrochemicals have had a dramatic impact on our food, clothing, shelter and leisure because they are the least expensive, most readily available, and can be processed most easily into the end use products. Petrochemical industry, which is known as one of the typical cycle profitability businesses, is now moving downward. In order to overcome the anticipated loss of profit, petrochemical companies are making an effort to offer a value-added upgrading to conventional products. This lecture will discuss a few of issues on the current status and prospect of petrochemical industry.