• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.393-402
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• 2021

In this study, a mixed matrix membrane was prepared by putting the zeolitic imidazolate framework-7 (ZIF-7) synthesized in Pebax-1657 and Pebax-2533, which are representative poly(ether-b-amide), and the permeability properties of single gas such as N₂ and CO₂ were investigated. From the gas permeation results, in the case of N₂, both the Pebax-1657/ZIF-7 and Pebax-2533/ZIF-7 mixed matrix membranes showed a similar phenomenon in which the permeability decreased with the incorporation of ZIF-7. For CO₂ permeability, the tendency was slightly different depending on the type of polymer. In the Pebax-1657/ZIF-7 mixed membrane, the CO₂ permeability decreased in the range of 0~3 wt% of ZIF-7, and increased at higher contents. The CO₂ permeability of the Pebax-2533/ZIF-7 mixed matrix membrane gradually decreased without increasing the permeability in the range of 0~5 wt% of ZIF-7. Regarding CO₂/N₂ selectivity, both mixed films showed a tendency to increase with increasing the ZIF-7 content. In particular, Pebax-2533/ZIF-7 5 wt% showed the best gas permeation performance compared to other mixed matrix membrane. This is thought to be because ZIF-7 shows better compatibility with Pebax-2533 than that of Pebax-1657 and also better CO₂ selective property.

• Membrane Journal
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• v.24 no.5
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• pp.409-415
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• 2014

This study is aimed to separate propylene and propane using membrane process instead of NCC(Naphtha Cracking Center) $C_3$ splitter. Membrane process is a low energy consumption and eco-friendly process while $C_3$ splitter requires high energy consumption in petrochemical processes. In this study, high performance facilitated transport membrane (FTM) is used for propylene/propane separation. FTM module was prepared on top of porous polyetherimide hollow fiber using PVP/$AgBF_4$/TCNQ. We developed simulation program predicting the membrane separation properties under operation conditions. Separation properties of FTM module for propylene and propane were obtained from the simulation program based on the pure gas permeation data. Based on these results, it is predicted that an one-stage membrane process provides 99.5% of propylene at permeate side from a binary gas mixture of 95/5 vol% $C_3H_6$ / vol% $C_3H_8$ supplied as a feed gas.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1744-1754
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• 2014

The hepatitis C virus (HCV) RNA genome is replicated by an RNA replicase complex (RC) consisting of cellular proteins and viral nonstructural (NS) proteins, including NS5B, an RNA-dependent RNA polymerase (RdRp) and key enzyme for viral RNA genome replication. The HCV RC is known to be associated with an intracellular membrane structure, but the cellular components of the RC and their roles in the formation of the HCV RC have not been well characterized. In this study, we took a proteomic approach to identify stomatin, a member of the integral proteins of lipid rafts, as a cellular protein interacting with HCV NS5B. Co-immunoprecipitation and co-localization studies confirmed the interaction between stomatin and NS5B. We demonstrated that the subcellular fraction containing viral NS proteins and stomatin displays RdRp activity. Membrane flotation assays with the HCV genome replication-competent subcellular fraction revealed that the HCV RdRp and stomatin are associated with the lipid raft-like domain of membranous structures. Stomatin silencing by RNA interference led to the release of NS5B from the detergent-resistant membrane, thereby inhibiting HCV replication in both HCV subgenomic replicon-harboring cells and HCV-infected cells. Our results identify stomatin as a cellular protein that plays a role in the formation of an enzymatically active HCV RC on a detergent-resistant membrane structure.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3849-3856
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• 2015

Background: Cholangiocarcinoma (CCA), or bile duct cancer, is incurable with a high mortality rate due to a lack of effective early diagnosis and treatment. Identifying cytoplasmic membrane proteins of invasive CCA that facilitate cancer progression would contribute toward the development of novel tumor markers and effective chemotherapy. Materials and Methods: An invasive CCA cell line (KKU-100) was stimulated using TNF-${\alpha}$ and then biotinylated and purified for mass spectrometry analysis. Novel proteins expressed were selected and their mRNAs expression levels were determined by real-time RT-PCR. In addition, the expression of ALCAM was selected for further observation by Western blot analysis, immunofluorescent imaging, and antibody neutralization assay. Results: After comparing the proteomics profile of TNF-${\alpha}$ induced invasive with non-treated control cells, over-expression of seven novel proteins was observed in the cytoplasmic membrane of TNF-${\alpha}$ stimulated CCA cells. Among these, ALCAM is a novel candidate which showed significant higher mRNA- and protein levels. Immunofluorescent assay also supported that ALCAM was expressed on the cell membrane of the cancer, with increasing intensity associated with TNF-${\alpha}$. Conclusions: This study indicated that ALCAM may be a novel protein candidate expressed on cytoplasmic membranes of invasive CCA cells that could be used as a biomarker for development of diagnosis, prognosis, and drug or antibody-based targeted therapies in the future.

• Membrane Journal
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• v.24 no.3
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• pp.185-193
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• 2014

PDMS (polydimethylsiloxane)-HNT (halloysite nanotube) composite membranes were prepared with different amounts tendency of HNT 5, 10, 20 and 30 wt% and rubbery polymer PDMS. The characteristics of these membranes were studied by FT-IR, XRD, TGA, and SEM. Gas permeation experiment were performed under condition of $25^{\circ}C$ and $3kg/cm^2$. Gas permeability of $N_2$, $H_2$, $CH_4$, and $CO_2$ and selectivity were investigated by increasing the amount of HNT contents in the PDMS. In $H_2$, $N_2$, $CH_4$, and $CO_2$ gases, as increasing HNT contents from 0 to 30 wt%, decreasing value of the permeability were observed. The selectivity of ($CO_2/N_2$) was shown in the range of 14 to 44 and the range of selectivity of ($CO_2/CH_4$) was 3.0 to 7.0.

• Membrane Journal
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• v.23 no.1
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• pp.80-91
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• 2013

Metal-templated condensation of cyclohexanedione dioxime and phenylboronic acid in the presence of Fe(II) sulfate heptahydrate proceeds cleanly in methanol to furnish the Fe(II) clathrochelate. An organic/inorganic hybrid membranes composed of Fe(II) clathrochelate and polyethersulfone was prepared by using phase inversion method. For membrane preparation, the Fe(II) clathrochelate was highly soluble (3~5 g/L) in DMF, NMP, and DMAc, which meets the requirements for the solubility of metal complexes in polar aprotic solvent used in membrane preparation. It was stable even in the presence of strong acids, such as trifluorosactic acid (pKa = 0.3). It was characterized by UV-vis spectroscopy, and their stability in solution phase studied in the presence of (i) strong acids or (ii) competing chelates. Organic/inorganic hybrid membranes were prepared with polyethersulfone, polyvinylpyrrolidone, p-toluenesulfonic acid, Fe(II) clathrochelate and DMF by using nonsolvent induced phase inversion method. The addition of Fe(II) clathrochelate leads increase of surface pore density, mean pore size and flux. We can obtain highly asymmetric membranes by addition of Fe(II) clathrochelate.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.164-169
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• 2008

In this study, the facilitated transport membranes, poly (ether ether)ketone (SPEEK)-Ag salts layers on top of polycarbonate supports membrane, were prepared and tested for the separation of propylene/propane. SPEEK was synthesised using PEEK and $H_2SO_4$. Experiments were porformed at room temperature and feed pressures up to 30 psig. The SPEEK-Ag salt membranes showed good selectivity for propane over propylene. With increasing the concentration of SPEEK in MeOH, 5~20 wt%, the thickness of SPEEK membrane on the polycarbonate increased. The selectivity and permeance of SPEKK-Ag membrane for propylene/propane were changed by membrane thickness and concentration of Ag salts.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.475-478
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• 2010

Fluorinated polymeric membranes were prepared by direct surface modification of PDMS with fluorine gas ($50{\sim}2000\;{\mu}mol/mol$ in nitrogen). The formed fluorinated polymeric membranes were characterized by FT-IR spectroscopy, GC (Gas chromatography), atomic force microscopy, and scanning electron microscopy. Direct fluorination resulted in the change of permeability and selectivity of various gases (pure gases such as $CO_2$, $O_2$, $N_2$, $C_2H_4$, mixture of He, Ne, Kr, Xe) through PDMS membranes. Fluorination resulted in the maximum 50% increase of selectivity through PDMS membrane.

• Journal of the Korean Magnetic Resonance Society
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• v.18 no.2
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• pp.58-62
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• 2014

Human transmembrane proteins (hTMPs) are closely related to transport, channel formation, signaling, cell to cell interaction, so they are the crucial target of modern medicinal drugs. In order to study the structure and function of these hTMPs, it is important to prepare reasonable amounts of proteins. However, their preparation is seriously difficult and time-consuming due to insufficient yields and low solubility of hTMPs. We tried to produce large amounts of Syndecan-4 transmembrane domain (Syd4-TM) that is related to the healing wounds and tumor for a long time. In this study, we performed the structure determination of Syd4-TM combining the Polarity Index at Slanted Angle (PISA) wheel pattern analysis based on $^{15}N-^1H$ 2D SAMPI-4 solid-state NMR of expressed Syd4-TM and Molecular Dynamics (MD) simulation using Discovery Studio 3.1.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.4
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• pp.129-137
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• 2016

Transmembrane(TM) proteins are closely related to transport, channel formation, signaling, cell to cell interaction, so they are the crucial target of modern medicinal drugs. In order to study the structure and function of these TM proteins, it is important to prepare reasonable amounts of proteins. However, their preparation is seriously difficult and time-consuming due to insufficient yields and low solubility of TM proteins. We tried to produce large amounts of Syndecan-4 containing TM domain(SDC4-TM) that is related to the wound healing and tumor. Also, mutated SDC4-TM was studied to investigate structural change by modification of dimerization motif. We performed the structure determination by the Polarity Index at Slanted Angle (PISA) wheel pattern analysis based on $^{15}N-^1H$ 2D SAMPI-4 solid-state NMR of SDC4-TM and computational modeling using Discovery Studio 2016.