• Title/Summary/Keyword: Transport

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Pharmacokinetic Modeling and Simulation of the Carrier-Mediated Hepatic Transport of Organic Anions (음이온계 약물의 간수송과정에 있어서 담체매개 수송의 약물동력학적 모델링 및 시뮬레이션)

  • 이준섭;강민희;김묘경;이명구;정석재;심창구;정연복
    • YAKHAK HOEJI
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    • v.47 no.2
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    • pp.110-119
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    • 2003
  • The purpose of the present study was to kinetically investigate the carrier-mediated uptake in the hepatic transport of organic anions, and to simulate the ″in vivo counter-transport″ phenomena, using kinetic model which was developed in this study. 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 a organic anion were then kinetically analyzed based on a flow model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). Moreover, ″in vive counter-transport″ phenomena were simulated based on the perfusion model which incorporated the carrier-mediated transport and the saturable intracellular binding. The ″in vivo counter-transport″ phenomena in the hepatic transport of a organic anion were well demonstrated by incorporating the carrier-mediated process. However, the ″in vivo counter-transport″ phenomena may be also explained by the enhancement of back diffusion due to the displacement of intracellular binding. In conclusion, one should be more cautious in interpreting data obtained from so-called ″in vivo counter-transport″ experiments.

Effects of Phloretin, Cytochalasin B, and D-Fructose on 2-deoxy-D-Glucose Transport of the Glucose Transport System Present in Spodoptera frugiperda Clone 21-AE Cells

  • Lee Chong-Kee
    • Biomedical Science Letters
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    • v.12 no.1
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    • pp.17-22
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    • 2006
  • The baculovirus expression system is a powerful method for producing large amounts of the human erythrocyte-type glucose transport protein, heterologously. Characterization of the expressed protein is expected to show its ability to transport sugars directly. To achieve this, it is a prerequisite to know the properties of the endogenous sugar transport system in Spodoptera frugiperda Clone 21 (Sf21) cells, which are commonly employed as a host permissive cell line to support the baculovirus replication. The Sf21 cells can grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transport system. However, unlike the human glucose transport protein that has a broad substrate and inhibitor specificity, very little is known about the nature of the endogenous sugar transport system in Sf21 cells. In order to characterize further the inhibitor recognition properties of the Sf21 cell transporter, the ability of phloretin, cytochalasin B and D-fructose to inhibit 2-deoxy-D-glucose (2dGlc) transport was examined by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. The 2dGlc transport in the Sf21 cells was very potently inhibited by phloretin, the aglucone of phlorizin with a $K_i$ similar to the value of about $2{\mu}M$ reported for inhibition of glucose transport in human erythrocytes. However, the Sf21 cell transport system was found to differ from the human transport protein in being much less sensitive to inhibition by cytochalasin B (apparent $K_i$ approximately $10\;{\mu}M$). In contrast, It is reported that the inhibitor binds the human erythrocyte counterpart with a $K_d$ of approximately $0.12\;{\mu}M$. Interestingly, the Sf21 glucose transport system also appeared to have high affinity for D-fructose with a $K_i$ of approximately 5mM, contrasting the reported $K_m$ of the human erythrocyte transport protein for the ketose of 1.5M.

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Effects of transport stress on physiological responses and milk production in lactating dairy cows

  • Hong, Heeok;Lee, Eunchae;Lee, In Hyung;Lee, Sang-Rak
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.3
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    • pp.442-451
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    • 2019
  • Objective: This study was conducted to investigate the effect of transport stress on physiological and hematological responses and milk performance in lactating dairy cows. Methods: Ten lactating dairy cows were randomly divided into 2 groups. The treatment group (TG) was transported 200 km for 4 h by truck, and the control group (NTG) was restrained by stanchion for 4 h in Konkuk University farm. Blood and milk samples were collected at 24 h pre-transport; 1, 2, and 4 h during transport; and 2, 24, and 48 h post-transport. Milk yields were measured at 24 h pre-transport, 0 h during transport, and 24, 48, and 72 h post-transport. Results: Leukocyte, neutrophil, and monocyte numbers in the TG were significantly higher than those of the NTG at each experimental time point. Lymphocyte numbers in the TG were significantly (p<0.05) higher than those of the NTG at 48 h post-transport. Additionally, the neutrophil:lymphocyte ratio of the TG was 45% and 46% higher than that of the NTG at 4 h during transport and 2 h post-transport, respectively. There were no significant differences in erythrocyte numbers, hemoglobin concentrations, platelet numbers, and hematocrit percentages between two groups. Cortisol levels in the TG were significantly (p<0.05) higher than those in the NTG. Milk yields in the TG were lower than those in the NTG. The somatic cell count (SCC) of the TG was significantly (p<0.05) higher than that of the NTG at 1 and 2 h during transport; that of the TG increased dramatically at 1 h during transport and gradually decreased subsequently. Conclusion: Transport stress increased blood parameters including leucocyte, neutrophil, and monocyte numbers by increased cortisol levels, but did not affect erythrocytes, hemoglobin and hematocrit levels. Additionally, transport resulted in a decrease in milk yield and reduced milk quality owing to an increase in milk SCC.

A Study on the Meaning and Main Features of Transport Documents under the Rotterdam Rules (로테르담규칙상 운송서류의 의의 및 주요 특징에 관한 연구)

  • YANG, Jung-Ho
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.69
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    • pp.303-326
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    • 2016
  • The Rotterdam Rules regulate both transport documents and the legal effect of the choice of document much more comprehensively than the existing maritime convention to bring international harmonization of issues relating to transport documents. The Rotterdam Rules use the generic term 'transport documents' rather than referring to specific title such as bills of lading, sea waybills. The generic term 'transport documents' allow four types of transport documents to be identified as follows. 1. negotiable 2. negotiable which dispense with surrender 3. non-negotiable which require surrender 4. non-negotiable. Each types of transport documents has its requirements to be satisfied. Also, the choice of transport documents affects legal effect. Thus parties to the contract of carriage not only need to know how the document will be classified at the time it is issued but also consider what the documents will bring legal consequences.

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DMT Transport System Analysis for Rail Logistics Efficiency (철도물류 효율화를 위한 DMT수송시스템 현황분석)

  • Shin, Seung-Kwon;Kim, Seog-Won;Seo, Sung-Il
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1668-1673
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    • 2007
  • In light of the growing traffic congestion problem and congestion cost, the container transport by railway has to be increased. The freight transport by railway can have decided advantages over trucks in terms of energy efficiency, emissions and cost for certain freight movements, just as transportation in the metropolitan region can have great advantages over driving truck. But the freight transport by truck should gain significant mobility benefits from a freight railway system. Thus, the DMT(Dual Mode Trailer) transport system which is coupled railway transport advantages with load transport advantages has been developed and used in the european countries. The DMT transport will therefore serve the areas required by transport organizers. This paper describes the various DMT transport systems and its strength and weakness.

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Empirical Study of Multimodal Transport Route Choice Model in Freight Transport between Korea and Mongolia

  • Ganbat, Enkhtsetseg;Kim, Hwan-Seong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2015.10a
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    • pp.241-242
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    • 2015
  • According to globalization of world economy on distribution and sales, logistics and transportation parts are play important role. Especially, it important to know and study how to choose right transport route and which is the key factor of route choice model in multimodal transport system. Thus this study aims to consider 4 main factors: cost, delivery time, freight, and logistics service factors additionally dividing into 13 sub factors and object is forwarders between Mongolia and Korean freight transport. The survey is based on AHP through interview with company officials. The paper provides empirical insights about current status of Mongolian forwarders and difference of the important factors between transportation modes. Result shows that time factor is role factor to choose transport route and then cost factors. Additionally, this study shows 2 different route choose factors between air transport and shipping transport forwarders.

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A Study on Problems Arising from Application of the Retterdam Rules under International Multimodal Transport Contracts (국제복합운송계약에서 로테르담 규칙의 적용상 문제점에 관한 연구)

  • Yang, Jung-Ho
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.46
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    • pp.181-210
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    • 2010
  • The continuing advance of multimodal transport with the importance for efficient and effective logistics management emphasizes the need for uniform legal approach to international multimodal transport. However, the current fragmented instrument regulating such transport is being an obstacle to development of multimodal transport as it aggravates confusion and uncertainty. The Rotterdam rules, which was adopted in December 2008 by UNCITRAL, expands its scope of application to door-to-door transport. However, the new rules has some problems in its application to multimodal transport operation as it has been conceived not to regulate general multimodal carriage but to regulate contract of carriage by sea that extends its services to the transport by other modes. This article examines conflict of conventions in the Rotterdam Rules. The applicability of the Rotterdam Rules in international multimodal transport contract and possibility of potential conflict with other transport conventions are analyzed with some hypothetical cases. Furthermore, problems arising from application of the Rotterdam Rules under international multimodal transport Contracts are indicated in the chapter IV.

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Handling of IP Version for Interworking IP Transport and ATM Transport Mechanisms in a Radio Access Network (무선접속망에서 IP 전송 방식과 ATM 전송 방식간의 상호연동을 위한 IP 버전 처리)

  • Lee, Wan-Yeon
    • The KIPS Transactions:PartC
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    • v.9C no.5
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    • pp.627-636
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    • 2002
  • In this paper, we investigate the interworking method between three transport mechanisms, that is, ATM transport, IP$_v$4 transport and Ip$_v$6transport, where these mechanisms are wholly used in a Mobile RAN (Radio Access Network). The proposed interworking method, called Triple Capable Node, is to implement three transport mechanisms simultaneously in a single node so that the node can communicate directly to other nodes having various transport mechanisms by using one of three transport mechanisms. In addition, we propose a dynamic algorithm which selects one among multiple transport mechanisms at run time in order to achieve better communication performance.

A Study on Prediction of Sediment and Riverbed Variation According to Sediment Transportation Functions (유사량 산정공식에 따른 유사 및 하상변동 예측에 관한 연구)

  • Go, Su Hyeon;Song, In Ryeol;Kim, Chang Seok
    • Journal of Environmental Science International
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    • v.13 no.3
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    • pp.263-277
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    • 2004
  • The purpose of this study is to analyze the characteristics of riverbed variation due to the sediment protection weir located on the estuary of the main stream of Taehwa river using I-D finite difference model, HEC-6 model, and the followings are the results of estimating sediment transport rate, amount of scour or deposition, and accumulated amount of deposit according to before and after of the sediment protection weir removal with various flow rates in the channel. Ackers-White transport function produced the greatest sediment transport rate while Meyer-Peter showed the smallest sediment transport rate at the most down stream area of the watershed through the sediment transport rate analyses for various flow rates according to the existence or nonexistence of the sediment protection weir. Toffaleti's and Colby transport function were closest to the average value, and the difference among the results of the sediment transport functions showed up to 8~9 times. Duboy's transport function produced the greatest riverbed variation while Toffaleti's showed the smallest variation through the riverbed variation analyses according to the existence or nonexistence of the sediment protection weir. Yang's was closest to the average value, and the difference among the results of the riverbed variation analyses ranged from 1.4 times to 11 times. It is thought that a sediment transport function must be selected very carefully with respect to the criteria of sediment yield estimation because the analysis results of the sediment transport rate and riverbed variation according to flow rates showed significant differences among the sediment transport functions, and the differences of sediment transport rate and riverbed variation according to the various sediment transport functions decreased as the flow rate increased.

Study on the selection of transport route for import-export container cargo based on the environmental cost (환경비용을 고려한 수출입컨테이너 화물의 운송경로 선택에 관한 연구)

  • 김상현;고창두
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2003.05a
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    • pp.304-310
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    • 2003
  • In this paper, we investigate the selection of transport route for import-export container cargo based on the sacrifice model and environmental cost of transport route. At first, sacrifice model. environmental cost of transport, the transportation and the transport share of import-export container cargo are investigated briefly. And next, the transport time and cost, the environmental cost which is caused by cargo transport are investigated for the transport of import-export container cargo from Pusan Port to Seoul. And also we calculate the sacrifice of each route by using the sacrifice model including the environmental cost. Finally we decide the transport route of import-export container cargo by using the sacrifice of each transport route. From the research results, we confirm that the road transport share decreases and the coastal transport share increases when the environmental coast of transport is considered.

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