• Title/Summary/Keyword: Buffer Solution

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Addition of $B_2O_3$ precursors and their effect on texture and surface roughness of $La_2Zr_2O_7$ buffer layers

  • Kim, Young-Kuk;Yoo, Jai-Moo;Chung, Kook-Chae;Shin, Pyung-Woo
    • Progress in Superconductivity and Cryogenics
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    • v.10 no.2
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    • pp.20-23
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    • 2008
  • [ $La_2Zr_2O_7$] (LZO) buffer layers were deposited on biaxially textured Ni-W substrates by chemical solution deposition method (CSD). In this study, the effect of $B_2O_3$ addition on texture and surface roughness of LZO films was investigated. The alkoxide-based precursor solution was employed to synthesize the precursor solution of LZO and the solution was coated on biaxially textured Ni-W substrates and subsequently annealed at $900^{\circ}C$ for crystallization. The pure LZO film without $B_2O_3$ addition showed a (222) reflection in the X-ray diffraction (XRD) profile. The intensity of (222) reflection was enhanced and more rough surface was obtained after further repetition of coating. Contrary to this, the LZO film prepared by $B_2O_3$ added precursor solution shows well-developed (400) reflection peak in the XRD profile and excellent biaxial texture (${\Delta}{\theta}=4.3^{\circ}$, ${\Delta}{\phi}=6.8^{\circ}$). The surface roughness of LZO films were also improved by addition of $B_2O_3$ even after multicoating ($R_{rms}{\sim}3.1nm$). It was shown that the LZO film with smooth surface and biaxial texture was grown on the biaxially textured Ni-W substrates with addition of $B_2O_3$ in the precursor solution.

Molecular Association of Glucose Transporter in the Plasma Membrane of Rat Adipocyte

  • Hah, Jong-Sik
    • The Korean Journal of Physiology
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    • v.25 no.2
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    • pp.115-123
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    • 1991
  • Molecular association of glucose transporters with the other proteins in the plasma membrane was assessed by gel electrophoresis and immunoblot techniques. Approximately $31.5{\pm}5.1%$ of GLUT-4, $64.8{\pm}2.7%$ of clathrin, 48.7% of total protein in the plasma membrane (PM) were found insoluble upon extraction with 1% Tx-100. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the Tx-100 insoluble PM fraction contained about 4 major polypeptides with apparent molecular weight of above 200, 100-120, 80 and 30-35 KDa that were readily removed upon wash with a high pH buffer which is known to remove clathrin and 0.5 M Tris-buffer which is known to remove assembly proteins (AP). Immunoblotting of GLUT4 and clathrin against specific antibodies showed that GLUT-4 and clathrin were co-solubilized up to 84.6% and 82.7% respectively by wash with a high pH buffer and 1% Tx-100. When the membrane was pre-washed with a high pH buffer and 0.5 M Tris solution, GLUT4 and clathrin were not solubilized further suggesting that GLUT4 molecules are in molecular association with clathrin, AP and/or other extrinsic membrane proteins in plasma membrane and the formation of clathrin-coated structures might be involved in insulin stimulated glucose transporter translocation mechanism.

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An Implementation of a High Speed Elasticity Buffer (초고속 신축버퍼의 구현)

  • Hong, You-Pyo;Yang, Gi-Joo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.8C
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    • pp.801-805
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    • 2009
  • The importance of high-speed networking is ever increasing to better support multimedia application such as video conferencing. It is crucial to synchronize the network so that the delay between computers on the network is minimized. In high-speed LAN, for example, most computers use clocks with almost same frequency to minimize the delay for data transmission. However, because of the deviation of transmitter's and receiver's clock frequency and phase difference there can be a metastability problem. Elasticity buffer is to provide a solution for this situation and this paper presents an implementation is a high-speed elasticity buffer.

Receiver-centric Buffer Blocking-aware Multipath Data Distribution in MPTCP-based Heterogeneous Wireless Networks

  • Cao, Yuanlong;Liu, Qinghua;Zuo, Yi;Ke, Fenfen;Wang, Hao;Huang, Minghe
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.10
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    • pp.4642-4660
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    • 2016
  • One major concern of applying Multipath TCP (MPTCP) to data delivery in heterogeneous wireless networks is that the utilization of asymmetric paths with diverse networking-related parameters may cause severe packet reordering and receive buffer blocking (RB2LOC). Although many efforts are devoting to addressing MPTCP's packet reordering problems, their sender-controlled solutions do not consider balancing overhead between an MPTCP sender and receiver, and their fully MPTCP mode cannot make MPTCP achieve a desired performance. This paper proposes a novel receiver-centric buffer blocking-aware data scheduling strategy for MPTCP (dubbed MPTCP-rec) necessitating the following aims: (1) alleviating MPTCP's packet reordering and RB2LOC problems, (2) improving the MPTCP performance, and (3) balancing load between the MPTCP sender and receiver. Simulation results show that the proposed MPTCP-rec solution outperforms the existing MPTCP solutions in terms of data delivery performance in heterogeneous wireless networks.

Preparation and Rheological Properties of Chitin and Chitosan -2. Effects of shear rate, temperature, concentration and salts on the viscosity of chitosan solution- (갑각류 외피의 유효이용을 위한 Chitin 및 Chitosan의 제조와 물성학적 특성에 관한 연구 -2. Chitosan 용액의 점도에 미치는 전단속도, 온도, 농도 및 염의 영향-)

  • LEE Keun-Tai;PARK Seong-Min;BAIK Oon-Doo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.28 no.4
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    • pp.397-400
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    • 1995
  • Effects of rheological parameters, such as shear rate, temperature, concerntration, salts on the apparent viscosity of chitosan(deacetylation degree: $84\%$, Mw: 267,000) dissolved in acetate buffer(pH 4.5) were investigated. Rheologiral properties of chitosan solution from cuticle of red snow crab (Chinonecetes japonicus) are as follows. $0.5\%$ chitosan in 0.1M acetate buffer (pH 4.5) solution showed Bingham flow having hysteresis loop. It's flow equation was $\sigma=0.757+19.6_\gamma(r^2=0.99)$. The viscosity of chitosan solution is exponentially increased with its concentration, and showed Arrhenius dependence with respect to the temperature $(10^{\circ}C-40^{\circ}C).$ When various salts were added to chitosan solution, the viscosity decreased as the concentration of counterion increased. But the type ot counterions itself does not have any significant effects on the viscosity.

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Compositional Effects of $CaO-SiO_2-P_2O_5$ Bioactive Cement on Hardening and Hydroxyapatite Formation ($CaO-SiO_2-P_2O_5$계 바이오 시멘트 유리의 조성이 경화 및 Hydroxyapatite 형성에 미치는 영향)

  • 박상종;김철영
    • Journal of the Korean Ceramic Society
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    • v.31 no.5
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    • pp.505-512
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    • 1994
  • It has been reported that a biocement obtained by mixing CaO-SiO2-P2O5 glass powder and ammonium phosphate solution has biocompatibility as well as high strength. However, the compositional dependence on its hardening and hydroxyapatite formation phenomena has not been studied. Therefore, the main objective of this work is to study the effects of P2O5, MgO in CaO-SiO2 system glass on the hardening and hydroxyapatite formation. When more than 50 mole% of CaO containing CaO-SiO2 glasses was reacted with ammonium phosphate solution, CaNH4PO4.H2O crystal was formed, but the glass with less than 50 mol% of CaO formed (NH4)2HPO4 and NH4H2PO4 crystals which are derived from ammonium phosphate solution without reacting with the glasses. As the amount of P2O5 in CaO-SiO2-P2O5 glass system was increased, the formation of CaNH4PO4.H2O crystal was enhanced. When those hardened samples were reacted with tris-buffer solution, hydroxyapatite was obtained only for the sample with CaNH4PO4.H2O. While the substitution of MgO for CaO decreased the formation of CaNH4PO4.H2O crystal. MgNH4PO4.H2O crystla was formed in high MgO containing glass, which did not react with tris-buffer solution.

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Enhancement of Cultivation Efficiency of Bifidobacterium longum Using Calcium Carbonate Buffer System (Calcium Carbonate Buffer System을 이용한 Bifidobacterium longum의 배양 효율 증대에 관한 연구)

  • Lee, Ki-Yong;Hwang, In-Bum;Heo, Tae-Ryeon
    • Korean Journal of Food Science and Technology
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    • v.29 no.1
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    • pp.126-132
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    • 1997
  • Calcium carbonate ($CaCO_3$) immobilized with alginate was studied as buffer system to enhance the cultivation efficiency of Bifidobacterium longum (ATCC 15707) which is inhibited at low pH. To test the bufferring effect of the immobilized $CaCO_3$ beads, pH value in each modified trypticase-proteose peptone-yeast (TPY) broth which is adjusted to pH 4.0 with acetic acid, lactic acid and complex solution of acetic and lactic acid, 3:2 (M:M) was tested by concentration of $CaCO_3$ bead and reaction time. The bufferring effect of $CaCO_3$ bead became higher with increasing the amount of $CaCO_3$ bead in the acidic solution. The growth rate of bifidobacteria and bufferring effect were examined in relation to the amount of $CaCO_3$ bead and concentration of glucose in the modified TPY media. The growth rate of bifidobacteria and bufferring effect were increased with increasing the amount of $CaCO_3$ bead and concentration of glucose. Also, the exponential time of bifidobacteria became longer with increasing the amount of $CaCO_3$ bead and concentration of glucose in the modified TPY media. When we observed the growth rate of bifidobacteria by the method of pH-controlled culture and $CaCO_3$ buffer system, the $CaCO_3$ buffer system was more effective than that of pH-controlled culture. Therefore, this $CaCO_3$ buffer system may be useful as a method to enhance of the cultivation efficiency of bifidobacteria.

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Optimization of CdS buffer layers for $Cu_2ZnSnSe_4$ thin-film applications ($Cu_2ZnSnSe_4$ 태양전지의 적용을 위한 최적화 된 CdS 버퍼층 연구)

  • Kim, Gee-Yeong;Jeong, Ah-Reum;Jo, William
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.400-403
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    • 2012
  • $Cu_2ZnSnSe_4$(CZTSe) is emerged as a promising material for thin-film solar cells because of non-toxic, inexpensive and earth abundant more than $Cu(In,Ga)Se_2$ materials. For fabricating compound semiconductor thin-film solar cells, CdS is widely used for a buffer layer which fabricated by a chemical bath deposition method (CBD). Through the experiment, we controlled deposition temperature and mol ratio of solution conditions to find the proper grain 크기 and exact composition. The optimum CdS layers were characterized in terms of surface morphology by using a scanning electron microscope (SEM) and atomic force microscope (AFM). The optimized CdS layer process was applied on CZTSe thin-films. The thickness of buffer layer related with device performance of solar cells which controlled by deposition time. Local surface potential of CdS/CZTSe thin-films was investigated by Kelvin probe force microscopy (KPFM). From these results, we can deduce local electric properties with different thickness of buffer layer on CZTSe thin-films. Therefore, we investigated the effect of CdS buffer layer thickness on the CZTSe thin-films for decreasing device losses. From this study, we can suggest buffer layer thickness which contributes to efficiencies and device performance of CZTSe thin-film solar cells.

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Effect of Ammonia and pH on the Degradation of Aflatoxin $B_1$ during the Storage of Korean Soy Sauce(Kanjang) (간장 저장중 암모니아와 pH가 Aflatoxin $B_1$의 파괴에 미치는 영향)

  • Park, Kun-Young;Lee, Eun-Suk
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.18 no.1
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    • pp.115-122
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    • 1989
  • The mechanisms of aflatoxin $B_1(AFB_1)$ degradation by ammonia and alkaline pH during the storage of Korean soy sauces were studied. In the 0.05%, 0.1% and 0.5% of ammonia solutions, almost all of $AFB_1$(96-100%) was degraded after 2 to 24 hrs of incubation at $30^{\circ}C$. Increased levels of ammonia in both home made soy sauce(HMSS) and commercial soy sauce(CSS) caused slow increases in pH. The pH change was higher in CSS than in HMSS. The degradations of $AFB_1$ were not observed in the samples of HMSS, CSS, distilled water and 20 % of NaCl solution during the storage, however, when the pHs of the samples were adjusted to 10, the toxin was completely removed in all samples. $AFB_1$ was stable at pH 5 and 7 in bath buffer solutions and buffer solutions+0.2% ammonia, however, $AFB_1$ was degraded completely at pHs more than 9. $AFB_1$ was not degraded even at high concentrations of ammonia(0.2-1.0%) when the pH was maintained at 7 in the buffer solution. It indicated that ammonia content in the system was not important but the higher pH was the reason to degrade $AFB_1$. When the pHs of HMSS, CSS, buffersolution and buffer solution + 0.2% ammonia were adjusted to 5 and then reacted with $AFB_1$ for 5 days, the toxin was stable in all samples. However, when the pHs of the samples were adjusted to 7, about 60-70 % of $AFB_1$ was degraded in HMSS and CSS after 5 days of incubation during which the pH was not changed, but $AFB_1$ in the buffer solution and buffer solution + 0.2% ammonia was not degraded at all in the same conditions.

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Preparation and Evaluation of Bupivacaine-loaded Microspheres by Solvent Extraction Method

  • Kim, Min-Soo;Hwang, Sung-Joo
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.299.2-300
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    • 2003
  • Various bupivacaine-Ioaded microspheres were prepared with poly (d,l-Iactide) (PLA) by solvent extraction method. The internal solution of polymer(PLA R104) and drug in glacial acetic acid was introduced into the external phase of polyvinylpyrrolidone (PVP K-30) in polyethyleneglycol (PEG), and emulsified to be an oil-in-oil (o/o) emulsion. The o/o emulsion was poured to the buffer solution. (omitted)

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