• Title/Summary/Keyword: carrier transport

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Choline and basic amine drugs efflux from brain to blood across the blood-brain barrier

  • Lee, Na-Young;Kang, Young-Sook
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2003.11a
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    • pp.107-107
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    • 2003
  • The purpose of this study is to examine that the efflux transport system for choline from brain to blood is present at the blood-brain barrier (BBB) using brain efflux index (BEI) method. [$^3$H]Choline was microinjected into parietal cortex area 2 (Par2) region of rat brain, and was eliminated from the brain with an apparent elimination half life of 45 min. The BBB efflux clearance of [$^3$H]choline was 0.12 $m\ell$/min/g brain, which was calculated from the efflux rate constant (1.5${\times}$10$\^$-2/ min$\^$-1/) and the distribution volume in the brain slice (8.1 $m\ell$/g brain). This process was saturable and significantly inhibited by various organic cationic compounds including hemicholinium-3, tetraethylammonium chloride (TEA) and verapamil, by antioxidant, ${\alpha}$-phenyl-n-tert-butyl nitrone (PBN), and by Alzheimer's disease therapeutics, such as acetyl $\ell$-carnitine and tacrine. In conclusion, this finding is the first direct in vivo evidence that choline is transported from brain to the blood across the BBB via a carrier-mediated efflux transport process.

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Spray Characteristics of a Coal Slurry with Liquid Carbon Dioxide (고압 저등급탄-이산화탄소 슬러리 분무특성에 관한 연구)

  • KIM, CHANGYEON;KIM, HAKDUCK;SONG, JUHUN
    • Journal of Hydrogen and New Energy
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    • v.26 no.4
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    • pp.357-362
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    • 2015
  • There is potential method to utilize the liquid carbon dioxide ($LCO_2$) in coal gasification plants. The $LCO_2$ could be used to effectively transport coal particles instead of conventional carrier such as liquid water ($H_2O$) particularly in wet-fed gasifier. However, there is a lack of fundamental study on the atomization behavior of $LCO_2$ coal slurry under high pressure condition. In this study, the flashing spray characteristics of a coal mixture with $LCO_2$ was examined during a throttling process by using a flow visualization system. The spray of coal water slurry which is in the Rayleigh-type break up mode was significantly different. This difference indicates that the coal water slurry did not effectively transport the coal, as compared to $LCO_2$ coal slurry.

Cr (VI) separation by PolyHIPE membrane immobilized with Aliquat 336 by solvent-nonsolvent method

  • Chen, Jyh-Herng;Mai, Le Thi Tuyet;Hsu, Kai-Chung
    • Membrane and Water Treatment
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    • v.8 no.6
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    • pp.575-590
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    • 2017
  • PolyHIPEs membrane prepared with styrene (St), divinylbenzene (DVB), and ethylhexyl acrylate (EHA) can yield a unique pore structure provided by large voids highly interconnected by many small window throats. With the advantageous pore structure, PolyHIPE presents a potential as a support for carrier facilitated transport membrane. Tricaprylmethylammonium chloride (Aliquat 336) can be efficiently incorporated into the PolyHIPE membrane by a two-step solvent-nonsolvent method to obtain an Aliquat 336-immobilized PolyHIPE membrane with good stability. The study of Cr (VI) transport through Aliquat 336-immobilized PolyHIPE membrane indicates that the membrane has high initial flux and maxima stripping flux ($J_f^o=15.01({\mu}mol/m^2s)$, $J_s^{max}=6.15({\mu}mol/m^2s)$). The reusability study shows that the Aliquat 336-immobilized PolyHIPE membrane can maintain high Cr(VI) recovery efficiency even after 15 cycles of operations. The developed membrane was also used in the separation of Cr (VI) from other anions (i.e., $SO_4{^{2-}}$ and $NO_3{^-}$) and other cations (i.e., Ni (II), Mg (II) and Cu (II)) with good selectivity.

Electronic Structure of Organic/organic Interface Depending on Heteroepitaxial Growth Using Templating Layer

  • Lim, Hee Seon;Kim, Sehun;Kim, Jeong Won
    • Applied Science and Convergence Technology
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    • v.23 no.6
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    • pp.351-356
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    • 2014
  • The electronic structure at organic-organic interface gives essential information on device performance such as charge transport and mobility. Especially, the molecular orientation of organic material can affect the electronic structure at interface and ultimately the device performance in organic photovoltaics. The molecular orientation is examined by the change in ionization potential (IP) for metal phthalocyanines (MPc, M=Zn, Cu)/fullerene ($C_{60}$) interfaces on ITO by adding the CuI templating layer through ultraviolet photoelectron spectroscopy measurement. On CuPc/$C_{60}$ bilayer, the addition of CuI templating layer represents the noticeable change in IP, while it hardly affects the electronic structure of ZnPc/$C_{60}$ bilayer. The CuPc molecules on CuI represent relatively lying down orientation with intermolecular ${\pi}-{\pi}$ overlap being aligned in vertical direction. Consequently, in organic photovoltaics consisting of CuPc and $C_{60}$ as donor and acceptor, respectively, the carrier transport along the direction is enhanced by the insertion of CuI templaing layer. In addition, optical absorption in CuPc molecules is increased due to aligned transition matrix elements. Overall the lying down orientation of CuPc on CuI will improve photovoltaic efficiency.

Hall Effect of $FeSi_2$ Thin Film by Temperture ($FeSi_2$ 박막 홀 효과의 온도의존성)

  • Lee, Woo-Sun;Kim, Hyung-Gon;Kim, Nam-Oh;Chung, Hun-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.230-233
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    • 2001
  • FeSi2/Si Layer were grown using FeSi2, Si wafer by the chemical transport reactio nmethod. The directoptical energy gap was found to be 0.871eV at 300 K. The Hall effect is a physical effect arising in matter carrying electric current inthe presence of a magnetic field. The effect is named after the American physicist E. H. Hall, who discovered it in 1879. IN this paper, we study electrical properties of FeSi2/Si layer. And then we measured Hall coefficient Hall mobility, carrier density and Hall voltage according to variation magnetic field and temperature, Because of important part for it applicationVarious phase of silicide is formed at the metal-Si interface when transition metal contacts to Si. Silicides belong to metallic or semiconducting according to their electrical and optical properties. Metallic silicides are used as gate electrodes or interconnections in VLSI devices. Semiconducting silicides can be used as a new material for IR detectors because of their narrow energy band gap.

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Hall Effect of $FeSi_2$ Thin Film by Magnetic Field ($FeSi_2$ 박막 홀 효과의 자계의존성)

  • Lee, Woo-Sun;Kim, Hyung-Gon;Kim, Nam-Oh;Seo, Yong-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.234-237
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    • 2001
  • FeSi2/Si Layer were grown using FeSi2, Si wafer by the chemical transport reactio nmethod. The directoptical energy gap was found to be 0.871eV at 300 K. The Hall effect is a physical effect arising in matter carrying electric current inthe presence of a magnetic field. The effect is named after the American physicist E. H. Hall, who discovered it in 1879. IN this paper, we study electrical properties of FeSi2/Si layer. And then we measured Hall coefficient Hall mobility,carrier density and Hall voltage according to variation magnetic field and temperature, Because of important part for it applicationVarious phase of silicide is formed at the metal-Si interface when transition metal contacts to Si. Silicides belong to metallic or semiconducting according to their electrical and optical properties. Metallic silicides are used as gate electrodes or interconnections in VLSI devices. Semiconducting silicides can be used as a new material for IR detectors because of their narrow energy band gap.

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Effects of Ethanol on $Na^+-dependent$ Solute Uptake in Rabbit Renal Brush-Border Membrane Vesicles

  • Kim, Yong-Keun;Ko, Sun-Hee;Woo, Jae-Suk;Jung, Jin-Sup;Lee, Sang-Ho
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.2
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    • pp.191-198
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    • 1999
  • This study was undertaken to examine the effect of ethanol on $Na^+-dependent$ transport systems (glucose, phosphate, and dicarboxylate) in renal brush-border membrane vesicles (BBMV). Ethanol inhibited $Na^+-dependent$ uptakes of glucose, phosphate, and succinate in a dose-dependent manner, but not the uptakes of $Na^+-dependent.$ The $H^+/TEA$ antiport was reduced by 8% ethanol. Kinetic analysis showed that ethanol caused a decrease in $V_{max}$ of three transport systems, leaving $K_m$ values unchanged. Ethanol decreased phlorizin binding, which was closely correlated with the decrease in $V_{max}$ of $Na^+-glucose$ uptake. These results indicate that ethanol inhibits $Na^+-dependent$ uptakes of glucose, phosphate, and dicaboxylate and that the reduction in $V_{max}$ of $Na^+-glucose$ uptake is caused by a decrease in the number of active carrier proteins in the membrane.

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Estimation of Total Electron Content in the Ionosphere over the Korean Peninsula using Permanent GPS Stations Operated by Ministry of Land, Transport and Maritime Affairs (국토해양부 GPS 상시관측소를 활용한 한반도 전리층의 총전자수 추정)

  • Kim, Kyeong-Hui;Park, Kwan-Dong
    • Journal of Korean Society for Geospatial Information Science
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    • v.17 no.1
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    • pp.149-155
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    • 2009
  • To quantitatively analyze the positioning error due to the ionosphere over the Korean peninsula, we created 2-dimensional ionosphere map using 44 permanent Global Positioning System(GPS) stations operated by Ministry of Land, Transport, and Maritime Affairs. We estimated Vertical Total Electron Content(VTEC) in a fine rectangular grids of $0.1^{\circ}{\times}0.1^{\circ}$ resolution. The observables we used were phase-leveled pseudoranges which are linear combinations of pseudoranges and carrier phases. VTECs were computed for five days during January 25-29, 2003 using the data from 45 permanent stations. In comparison with the Global Ionosphere Map of the Center for Orbit Determination in Europe, RMS differences were at the level of 8 TECU(TEC Unit).

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Optimization of ship inner shell to improve the safety of seagoing transport ship

  • Yu, Yan-Yun;Lin, Yan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.3
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    • pp.454-467
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    • 2013
  • A practical Ship Inner Shell Optimization Method (SISOM), the purpose of which is to improve the safety of the seagoing transport ship by decreasing the maximum Still Water Bending Moment (SWBM) of the hull girder under all typical loading conditions, is presented in this paper. The objective of SISOM is to make the maximum SWBM minimum, and the section areas of the inner shell are taken as optimization variables. The main requirements of the ship performances, such as cargo hold capacity, propeller and rudder immersion, bridge visibility, damage stability and prevention of pollution etc., are taken as constraints. The penalty function method is used in SISOM to change the above nonlinear constraint problem into an unconstrained one, which is then solved by applying the steepest descent method. After optimization, the optimal section area distribution of the inner shell is obtained, and the shape of inner shell is adjusted according to the optimal section area. SISOM is applied to a product oil tanker and a bulk carrier, and the maximum SWBM of the two ships is significantly decreased by changing the shape of inner shell plate slightly. The two examples prove that SISOM is highly efficient and valuable to engineering practice.

A new method for ship inner shell optimization based on parametric technique

  • Yu, Yan-Yun;Lin, Yan;Chen, Ming;Li, Kai
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.1
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    • pp.142-156
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    • 2015
  • A new method for ship Inner Shell optimization, which is called Parametric Inner Shell Optimization Method (PISOM), is presented in this paper in order to improve both hull performance and design efficiency of transport ship. The foundation of PISOM is the parametric Inner Shell Plate (ISP) model, which is a fully-associative model driven by dimensions. A method to create parametric ISP model is proposed, including geometric primitives, geometric constraints, geometric constraint solving etc. The standard optimization procedure of ship ISP optimization based on parametric ISP model is put forward, and an efficient optimization approach for typical transport ship is developed based on this procedure. This approach takes the section area of ISP and the other dominant parameters as variables, while all the design requirements such as propeller immersion, fore bottom wave slap, bridge visibility, longitudinal strength etc, are made constraints. The optimization objective is maximum volume of cargo oil tanker/cargo hold, and the genetic algorithm is used to solve this optimization model. This method is applied to the optimization of a product oil tanker and a bulk carrier, and it is proved to be effective, highly efficient, and engineering practical.