• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.764-770
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• 2006

Dihydrochalcomycin (GERI-155), produced by Streptomyces sp. KCTC-0041BP isolated from Korean soil, is a 16-membered macrolide antibiotic consisting of two deoxysugar moieties at C-5 and C-20 positions of a branched lactone ring. The cloning and sequencing of a gene cluster for dihydrochalcomycin biosynthesis revealed a 63-kb nucleotide region containing 25 open reading frames (ORFs). The products of all of these 25 ORFs playa role in dihydrochalcomycin biosynthesis and self-resistance against the compounds synthesized. At the core of this cluster lies a 39.6-kb polyketide synthase (PKS) region encoding eight modules in five giant multifunctional protein-coding genes (gerSI-SV). The genes responsible for the biosynthesis of deoxysugar moieties, D-chalcose and D-mycinose, and their modification and attachment were found on either side of this PKS region. The involvement of this gene cluster in dihydrochalcomycin biosynthesis was confirmed by disruption of the dehydratase (DH) domain in module 3 of the PKS gene and by metabolite analysis.

• Ocean and Polar Research
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• 제23권4호
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• pp.401-410
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• 2001

Global climate change will alter many such properties of the Southern Ocean as temperature, circulation, stratification, and sea-ice extent. Such changes are likely to influence the species composition and activity of Antarctic marine microorganisms (protists and bacteria) which playa major role in deter-mining the concentration of atmospheric $CO_2$ and producing precursors of cloud condensation nuclei. Direct impacts of climate change on Antarctic marine microorganisms have been determined for very few species. Increasing water temperature would be expected to result in a southward spread of pelagic cyanobacteria, coccolithophorids and others. Growth rates of many species would be expected to increase slightly but nutrient limitation, especially micronutrients, is likely to result in a negligible increase in biomass. The extent of habitats would be reduced for those organisms presently living close to the upper limit of their thermal tolerance. Increased UVB irradiance is likely to favour the growth of those organisms tolerant of UVB and may change the trophic structure of marine communities. Indirect effects, especially those as a consequence of a diminution of the amount of sea-ice and increased upper ocean stratification, are predicted to lead to a change in species composition and impacts on both trophodynamics and vertical carbon flux.

• 대한간호
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• 제36권4호
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• pp.88-99
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• 1997

Applying effective coping strategies and reducing powerlessness for the chronic pain adjustment of musculoskeletal patients were researched for basic data in the development of nursing intervention. The subjects were 99 musculoskeletal patients with chronic pain. Data was gathered with direct interview using a questionnaire. With the SAS tool. data were analyzed for percentage. Pearson correlation. t-test. and ANOVA according to characteristics of variables. Internal consistency(alpha) coefficients were .91 for coping scales and .71 for powerlessness scales. The results are as follows: 1. Pain duration was mainly 6 - 12 months(52. 5%). 2. Primary pain site was mainly lower limbs(58.6%) and pain severity was a moderate level. 3. The preference of coping strategies was decreased in the order named in resting. seeking social support. exercise or stretch. guarding. and asking for assistance. 4. The longer pain duration. the more the coping strategies of asking assistance used. This was stastically significant(F=3. 35. p<.05). 5. The group with the experience of hospital admission was more powerless than the group without that(F=3. as. p<.01). 6. Pain severity and powerlessness were significantly positively correlated(r=.444. p<.001). Coping strategy applying and powerlessness were significantly negatively correlated(r=-. 288. p<.01). In consequence. the nurse should playa role as the supporter of patient's maximal usage of his resources in pain relief. adjustment, and control. The nurses should also develop for the nursing intervention of physical therapy and educational programs.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.666-672
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• 2003

Vacuolar degeneration of the gastric epithelial cells is a characteristic feature of the derangement of mucosa where Helicobacter pylori colonizes, and H. pylori vacuolating cytotoxin (VacA) has been suggested to playa key role in it. To elucidate the VacA-involved degenerative mechanism, VacA was purified, and its impact on degeneration of HeLa cells was determined. In the presence of ammonium chloride, cell vacuolation by VacA was dose-and time-dependent, however, no detectable degeneration of the cells was observed with the VacA concentration tested. A further increase of vacuolation was shown in cells pre-treated with diethyl pyrocarbonate (DEPC) , and this resulted in a change of the cell morphology to become spherical. Similar phenomena were also observed when HeLa cells were co-cultivated with intact H. pylori cells. It was remarkable to note that the degree of growth inhibition was proportional to the increase in vacuole formation, suggesting that the vacuolation rate would be critical for cell degeneration. Surprisingly, although VacA was itself inhibited by DEPC, its uptake was markedly increased by this agent, similar to that found in cells with Nabutyrate. These data indicate that the cell's tolerance of VacA transport may be critical for vacuolar degeneration and may be changeable during H. pylori inhabitation.

• Transactions on Electrical and Electronic Materials
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• 제6권5호
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• pp.238-242
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• 2005

The Pt counter electrode of a dye-sensitized solar cell (DSSC) plays a role in helping redox reaction of iodine ions in electrolyte, also, transferring electrons into electrolyte. In this case, it is expected that characteristics of Pt electrodes strongly depend on fabrication process and its surface condition. In this study, Pt electrodes were prepared by a electro-deposition and a RF magnetron sputtering. Electrochemical behavior of Pt electrodes was compared using cyclic-voltammetry and impedance spectroscopy. Surface morphology of Pt electrodes was investigated by FE-SEM and AFM. I-V characteristics of DSSC were measured and discussed in association with the surface properties of counter electrode. As a result, electrochemical properties of electro-deposited Pt electrode were superior to that of sputtered Pt electrode. This is likely that enlarged area of surface in electro-deposited Pt electrode in comparison with the case of sputtered Pt electrode playa role in enhancing such electrochemical properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.391-393
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• 2006

In this paper, we develop a portable game device with uncompressed HD video and high quality sound output. Portable game devices support not only game function but also various complex functions recently. It especially supports TV-Out port to play realistic game, connecting a large screen display device. But the video and audio output signals of conventional TV-out port have the low performance and these signals are analog output. So, it is difficult that the users enjoy realistic game with benefit of high resolution digital TV. We propose the game device output with uncompressed digital signal, which has no delay of video/audio signal, also has strong immunity to external noise. Since it supports a high resolution video and high quality sound, users can playa realistic game. First, we implement the HDMI to the game device and we test reliability with the various resolutions video inputs and audio inputs. The proposed method can be applied multimedia devices requiring high performance output function as well as portable devices.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.305-310
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• 2003

This study is intended to outline the lessons that can be learned from European experience of the opportunities and challenges involved in operating train ferries to carry freight. The study considers the various train ferry routes that have operated over recent years in Europe, examines their characteristics, and then proceeds to evaluate the economic viability of train ferries in general. On the basis of this analysis, we have attempted to outline the conditions that appear to be required under which Train Ferries may be competitive. This study shows that long crossing train ferries in Europe have survived where the adjacent railway systems handle a significant volume of domestic traffic and do themselves playa serious role in the transport industry. There is no reason to suppose railway wagons cannot be carried economically over long distances. Experience in Western Europe is that they are best operated as mixed road trailer and rail wagon services. Only the lower deck need carry railway wagons, which greatly simplifies loading and the physical construction of the ship. Existing road based ro-ro ferries can be adapted to become rail ferries. It is, however, essential that there is commercial clarity as to the responsibility for ensuring the overall service is viable. To that end, the ferry company is responsible for marketing the service and managing relationships between the two railway authorities.

• 통상정보연구
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• 제4권2호
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• pp.131-153
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• 2002

An information technology revolution is sweeping the world driven by digitalization and tremendous popularity of the Internet. Electronic commerce and trade is the mainstream of this trend, and realization of a cyberspace without physical, spatial, and time restraints has led radical structural changes in international trade. Northeast Asia including Korea, China and Japan is becoming more important as a core economic region in terms of economic growth, intra-regional trade in particular. The introduction to electronic trade system and networks would playa vital role in speeding up trade of commodities, service and information etc. Therefore the study aims to examine a scheme to facilitate international trade in Northeast Asia by establishing information infrastructures. The study begins with reviewing current situation in information infrastructure such as the number of PC, utilization ratio of internet, information network, volume of electronic commerce. It is analyzed that what kinds of obstacles to facilitating electronic trade in Northeast Asian countries in terms of physical infrastructure, institutions, regulations, technologies regarding information exchange among countries. Finally this study presents some suggestions in order to remove the problems currently existed in vitalizing electronic trade.

• 대한의생명과학회지
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• 제13권1호
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• pp.39-45
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• 2007

Numerous psychological stressors playa role in development of the cardiovascular disease. The aim of this study was to determine whether a combined mental activity with experimental subway noise affects hematological physiology. Fifty-four healthy volunteers were divided group I which underwent subway noise (n=24) and group II which underwent a combined mental activity with subway noise (n=30). Venous blood samples were collected for measuring CBC, prothrombine time (PT), activated partial thromboplastine time (APTT), erythrocyte sedimentation rate (ESR), D-dimer and high sensitive C-reactive protein (H-CRP) levels before, 50 min of stress task (S-50m) and 60 min of recovery (R-60m). Changed ratios of granulocyte, lymphocyte, monocyte and platelet counts at S-50m and R-60m were higher in group II compared to group I. RBC count and hematocrit level in group I increased whereas those in group II decreased at S-50m. PT, APTT and ESR in the both groups were shortened at R-60m and the decreased ratios were high in group II compared to group I. H-CRP and D-dimer in the both groups were elevated at S-50m and R-60m while the increased ratios in group II were greater than those in group I. These observations imply that a combined mental activity with experimental subway noise may be a stressor which affects hematological physiology.

• 대한의생명과학회지
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• 제12권3호
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• pp.255-259
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• 2006

Reactive oxygen species (ROS) is one of the main pathological factors in endothelial disorder. For example, an atherosclerosis is induced by the dysfunction of vascular endothelial cells. The dysfunction of vascular endothelial cells cascades to secrete intercellular adhesion molecule (ICAM)-l substance by ROS. Therefore, The ROS is regraded as an important factor of the injury of vascular endothelial cells and inducement of atherosclerosis. Oxygen radical scavengers playa key role to prevention of many diseases mediated by oxidative stress of ROS. In this study, the toxic effect of ROS on vascular endothelial cells and the effect of antioxidant, vitamin E on bovine pulmonary vascular endothelial cell line (BPVEC) treated with hydrogen peroxide were examined by the colorimetric assay. ROS decreased remarkably cell viability according to the dose- and time-dependent manners. In protective effect of vitamin E on BPVEC treated with hydrogen peroxide, vitamin E increased remarkably cell viability compared with control after BPVEC were treated with $15{\mu}M$ hydrogen peroxide for 6 hours. From these results, it is suggested that ROS has cytotoxicity on cultured BPVEC and oxygen radical scavenger such as vitamin E is very effective in prevention of oxidative stress-induced cytotoxicity.