• Title/Summary/Keyword: Transport

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Kinetic Analysis of the Counter-transport Phenomenon in the Hepatic Transport of Organic Anionic Drugs (유기 음이온계 약물의 간수송과정에 있어서 대향수송현상에 관한 속도론적 연구)

  • Chung, Youn-Bok;Han, Kun;No, Jung-Ryul
    • Journal of Pharmaceutical Investigation
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    • v.22 no.4
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    • pp.289-300
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    • 1992
  • The counter-transport phenomena in the hepatic transport of 1-anilino-8-naphthalene sulfonate (ANS) were kinetically investigated by analyzing the plasma disappearance-time profiles and the transport into the isolated hepatocytes. In vivo "counter transport phenomena" were simulated based on the perfusion model which incorporated the carrier-mediated transport and the saturable intracellular binding. The condition that the mobility of carrier-ligand complex is greater than that of free carrier is not essential for the occurrence of counter-transport phenomenon. To examine the inhibitory effects on the initial uptake of a ligand by the liver, it is necessary to judge whether the true counter-transport mechanism (trans-stimulation) is working or not. The initial plasma disappearance curves of ANS were then kinetically analyzed based on a two-compartment model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). No effects on the initial plasma disappearance rates of ANS were observed after preloading of bromophenol blue (BPB) or rose bengal (RB) in the liver. Inhibitory effect of BPB or RB on the initial uptake (or efflux) rates of ANS by the isolated hepatocytes were not observed, suggesting that the true counter transport mechanism is not working. In conclusion, checking the preloading effects of transstimulation on the initial uptake of a ligand by the liver could be a useful criterion for carrier cycling and common use of the same carrier between two ligands. However, one cannot exclude those possibilities even if the preloading effects cannot be observed.

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A Research on Prospect of International Intermodal Transport in North-East Asia and Establishment of Transit Transport Agreement (동북아 국제복합운송 전망과 통과운송 협약의 추진방안 연구)

  • Park, Yong-An
    • Journal of Korea Port Economic Association
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    • v.27 no.2
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    • pp.163-182
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    • 2011
  • This research addresses the prospect of international intermodal transport in North-East Asia and studies the necessity of an agreement in transit transport in the region. Due to the division of labour among countries in the region and the globalization of firm's activities, international intermodal transport has been actively developed and is expected to grow continually. In order to lead the operation of international intermodal transport in North-East Asia, main players such as China and Russia have strengthened cooperation of regional logistics and made agreements in transit transport with contiguous countries. After analysing the current situation and reviewing prospects of international intermodal transport and transit transport in North-East Asia, this research proposes the requirement of regional agreement of transit transport on the basis of the United Nations Convention on the Law of the Sea (UNCLOS) for promoting international intermodal transport in North-East Asia.

An Experimental Study on the Sediment Transport Characteristics Through Vertical Lift Gate (연직수문의 퇴적토 배출특성에 관한 실험적 연구)

  • Lee, Ji Haeng;Choi, Heung Sik
    • Ecology and Resilient Infrastructure
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    • v.5 no.4
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    • pp.276-284
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    • 2018
  • In order to analyze sediment transport characteristics of knickpoint migration, sediment transport length, and sediment transport weight through the under-flow type vertical lift gate, the hydraulic model experiment and dimensional analysis were performed. The correlations between Froude number and sediment transport characteristics were schematized. The multiple regression formulae for sediment transport characteristics with non-dimensional parameters were suggested. The determination coefficients of multiple regression equations appeared high as 0.618 for knickpoint migration, 0.632 for sediment transport length, and 0.866 for sediment transport weight. In order to evaluate the applicability of the developed hydraulic characteristic equations, 95% prediction interval analysis was conducted on the measured and the calculated by multiple regression equations, and it was determined that NSE (Nash-Sutcliffe Efficiency), RMSE (root mean square), and MAPE (mean absolute percentage error) are appropriate, for the accuracy analysis related to the prediction on sediment transport characteristics of kickpoint migration, sediment transport length and weight.

Changes on the Methylmercury-induced Cytotoxicity by Control of Cell Membrane Transport System (세포막 물질수송계의 조절에 의한 유기수은의 세포독성 변화에 대한 연구)

  • 염정호;고대하;김준연;김남송
    • Journal of Environmental Health Sciences
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    • v.26 no.4
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    • pp.88-96
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    • 2000
  • The aim of the current study was to evaluate the transport system in EMT-6 cell for the uptake of the methylmercury(MeHg). Several inhibitors ere used to test used to test which potential transport system might be involoved in MeHg uptake. Probenecid was used to test the organic transport system, valinomycin for testing the effect of the membrane potential, cytochalasin B for testing the facilitated diffusive D-glucose transport system and colchicine for testing the microtubule system. Ouabain for evaluating active transport system, 4',4-diisothiocyano-2',2-stilbenedisulfonic acid(DIDS) the Cl- ion transport system and verapamil for the $Ca^{2+}$ transprot system. Significantly, MeHg decreased the synthesis of nitric oxcide(NO) and intracellular ATP in ENT-6 cells. In the condition of ouabain containing with MeHg decreased the production of NO and intracelluar ATP. In the treatment of inhibitors, ouabain showed protective effect against cytotoxicity of MeHg but ather inhibitors not showed protective effects. The protective effects of ouabain against the cytotoxicity of MeHg deoended on the concentration of added ouabain to the culture medium for MET-6 cells. These result showed that the uptake of MeHg might be involved in the active transport system. Active transports system seems to share similarities with the transport systems for the uptake of MeHg when using MeHg and MeHg-glutathione complex.x.

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Innovations as an Option to Increase the Market Share of Rail Freight Transport in Europe

  • Wiegmans, Bart W.
    • International Journal of Railway
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    • v.2 no.2
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    • pp.80-92
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    • 2009
  • Successful market adoption of rail freight transport innovations that might offer opportunities for market share increase is the focus of this paper. Firstly, seen from a theoretical point of view, it is not incremental innovations but radical organizational and transformation innovations that are likely to increase the market share of rail freight transport. Secondly, the particular inovations that offer some success potential for market adoption are: dedicated infrastructure, the fixed timetable, locomotive upgrades, and INTERFACE. Thirdly, unfortunately, the opportunities to increase the market share of rail freight transport appear to be limited.

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Transport Coefficients across Charged Mosaic Membrane

  • Yang, Wong-Kang
    • Bulletin of the Korean Chemical Society
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    • v.25 no.5
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    • pp.665-667
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    • 2004
  • In previous studies, charged mosaic membranes having two different fixed charges in the membrane matrix indicated unique transport behavior such as preferential material transport. In this study, the composite charged mosaic membrane endurable to mechanical pressure in practical application was investigated from the same aspect of solute and solvent transport as before. Lp and ${\omega}$ estimated by taking account of active layer thickness were satisfactorily consistent with those in mosaic membrane without reinforcement. On the other hand, the reflection coefficient s indicated the negative value that suggests preferential material transport.

Effect of Polyamine on Auxin Polar Transport in Corn Coleoptile Segments (Polyamine이 옥수수 자엽초 절편에서 오옥신 이동에 미치는 영향)

  • 허윤정
    • Journal of Plant Biology
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    • v.34 no.4
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    • pp.297-302
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    • 1991
  • The effects of polyamines on auxin polar transport were studied in corn coleoptile segments. Among putresine, spermidine and spermine tested in labelled auxin transport, spermidine inhibited auxin polar transport most strongly. Its inhibitory effect appeared after 1 h of transport period. Spermidine inhibited labelled auxin and 14C-benzoic acid accumulation into the tissue in the various pH range tested (pH 4.0-8.0). These results suggest that the inhibition of auxin transport may not be due to decrease in pH by spermine the effect of decreased pH in the extracellular space.

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A study on the exchange Kaesong area of goods transport train by the inter-Korean Railway Connection (남북철도 연결에 따른 개성지역 화물열차운행에 대한 연구)

  • Park Hong-Soon
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1671-1676
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    • 2004
  • This thesis watches for the present condition of both economic exchange and goods transport between South and North Korea focused on material side as a provision for the railway connection between them. This is also a predicting thesis for a smooth goods transport in case of setting up a goods transport system between south and North Korea predicting transport demand for the connection of a railway and road studying fundamental facilities and transport related laws.

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Implementation of RTP based Image Transport System using JPEG2000 (RTP 기반의 JPEG2000 영상 전송 시스템 구현)

  • 박동진;정영기
    • Proceedings of the IEEK Conference
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    • 2002.06d
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    • pp.355-358
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    • 2002
  • In this paper, we propose RTP(Real-Time Transport Protocol) based image transport system to transport still images in real-time after JPEG2000 compression, which is still image compression standard for next generation. To add RTP packet on UDP packet, the image transport system inserts packetizer and depacketizer process into transmitter and receiver of RTP data, respectively. We apply the proposed system to several image and compare the transport time to TCP-based method.

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A study on the Exchange of goods transport freight by the Inter-Korean Railway Connection (남북철도 연결에 따른 화물운송에 대한 연구)

  • Park Hong-Soon
    • Proceedings of the KSR Conference
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    • 2003.05a
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    • pp.190-195
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    • 2003
  • This thesis watches for the present condition of both economic exchange and goods transport between South and North Korea focused on material side as a provision for the railway connection between them. This is also a predicting thesis for a smooth goods transport in case of setting up a goords transport system between south and North Korea predicting transport demand for the connection of a railway and road studying fundamental facilities and transport related laws.

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