• 제목/요약/키워드: Transport

검색결과 15,422건 처리시간 0.043초

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

  • 정연복;한건;노정렬
    • Journal of Pharmaceutical Investigation
    • /
    • 제22권4호
    • /
    • pp.289-300
    • /
    • 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.

  • PDF

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

  • 박용안
    • 한국항만경제학회지
    • /
    • 제27권2호
    • /
    • pp.163-182
    • /
    • 2011
  • 이 연구는 동북아 지역의 국제복합운송의 현황과 전망을 분석하고 지역내 통과운송 협약의 필요성과 추진방안을 검토하였다. 이 연구에 따르면, 동북아 국가들간 교역확대와 경제협력 긴밀화에 따라 국제복합운송과 통과운송이 지역내 혹은 지역과 타 경제권간 활발하게 전개되어 왔으며, 향후에는 더욱 확산될 것으로 보인다. 동북아 주요 국가들인 중국, 러시아 등은 육상운송에서 국제복합운송 경로를 주도하기 위해, 내륙 국가들과 통과운송 협약을 체결하는 등 역내 물류협력을 강화하여 왔다. 이 연구는 동북아 국가들의 국제복합운송과 통과운송에 대한 수요증가, 물류기기와 장비의 확보와 운영, 새로이 부각되는 환경문제 등을 동북아 국가들이 공동적으로 대처할 것을 지적하는 한편 유엔해양법 협약에 기초한 통과운송에 대한 지역적 국제협약의 필요성을 제시한다.

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

  • 이지행;최흥식
    • Ecology and Resilient Infrastructure
    • /
    • 제5권4호
    • /
    • pp.276-284
    • /
    • 2018
  • 하단배출 형태의 연직수문을 대상으로 퇴적토 배출특성에 따른 두부침식 거리비, 퇴적토 이동거리와 이동량을 분석하기 위해 수리 모형실험과 차원해석을 수행하였다. Froude 수와 배출특성의 상관관계를 도식화하고, 퇴적토 배출특성을 지배하는 무차원 매개변수에 의한 다중회귀식을 제안하였다. 두부침식거리, 퇴적토 이동거리와 이동량에 대한 각 다중회귀 분석식의 결정계수는 각각 0.618, 0.632, 0.866으로 높게 나타났다. 개발한 퇴적토 배출특성식의 사용성을 평가하기 위해 실제 측정값과 회귀분석식에 의해 계산된 값의 95%의 예측 신뢰구간 분석을 수행하였고, 두부침식거리, 퇴적토 이동거리와 이동량에 대한 예측의 정확도 분석차원의 NSE (Nash-Sutcliffe Efficiency), RMSE (root mean square)와 MAPE (mean absolute percentage error)는 적절한 것으로 판단되었다.

Modeling and Trends of Road Transport Development in Eastern European Countries

  • Viktoriia Harkava;Olena Pylypenko;Oleksandr Haisha;Armen Aramyan;Volodymyr Kairov
    • International Journal of Computer Science & Network Security
    • /
    • 제24권3호
    • /
    • pp.189-195
    • /
    • 2024
  • Road transport occupies the largest share in domestic and international transport. It is of key importance for the development of the economy, forasmuch as it provides the livelihood of the population, the development of the national economy, the possibility of establishing foreign economic relations. The purpose of the research is as follows: analysis of the current state of functioning of the road transport sector in Eastern Europe and identification of key problems and trends in its development. Research methods: Methods of grouping, comparison and generalization, correlation analisys have been used to identify the dynamics of the main indicators of road transport in Eastern Europe. The method of correlation-regression analysis has been applied to determine the impact of increasing the length of roads on the turnover of the road freight transport and the number of employed population in this area. Results. It has been found that the increase in the employed population by 96% and increase in revenues from transportation and storage of goods, postal and courier services (turnover of the road freight transport - in the original language) in the field of road transport by 82% is explained by the change in transport infrastructure capacity by increasing length of highways. According to the correlation analysis, it has been revealed that there is a high direct dependence between the length of roads and increased revenues from transportation and storage of goods in the field of road transport, as well as between the length of roads and increasing employment in this area.

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

  • 염정호;고대하;김준연;김남송
    • 한국환경보건학회지
    • /
    • 제26권4호
    • /
    • pp.88-96
    • /
    • 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.

  • PDF

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

  • Wiegmans, Bart W.
    • International Journal of Railway
    • /
    • 제2권2호
    • /
    • pp.80-92
    • /
    • 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.

  • PDF

Transport Coefficients across Charged Mosaic Membrane

  • Yang, Wong-Kang
    • Bulletin of the Korean Chemical Society
    • /
    • 제25권5호
    • /
    • pp.665-667
    • /
    • 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.

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

  • 허윤정
    • Journal of Plant Biology
    • /
    • 제34권4호
    • /
    • pp.297-302
    • /
    • 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.

  • PDF

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

  • 박홍순
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2004년도 추계학술대회 논문집
    • /
    • pp.1671-1676
    • /
    • 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.

  • PDF

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

  • 박동진;정영기
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
    • /
    • pp.355-358
    • /
    • 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.

  • PDF