• Membrane Journal
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• v.31 no.1
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• pp.61-66
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• 2021

This study was a study on an facilitated transport membrane to replace the cryogenic separation method currently used in olefin/paraffin separation. Cost reduction is also a very important factor to commercialize facilitated transport membranes. However, AgBF4, which has been studied a lot, is a relatively expensive silver salt. To replace this, a PEBAX-2533/ AgCF3SO3/Al(NO3)3 composite film was prepared using relatively inexpensive AgCF3SO3. It was analyzed through SEM, FT-IR, and RAMAN. Through this study, it was confirmed that the polymer matrix affects the long-term stability.

• BMB Reports
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• v.54 no.3
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• pp.157-163
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• 2021

The transient interactions between cellular components, particularly on membrane surfaces, are critical in the proper function of many biochemical reactions. For example, many signaling pathways involve dimerization, oligomerization, or other types of clustering of signaling proteins as a key step in the signaling cascade. However, it is often experimentally challenging to directly observe and characterize the molecular mechanisms such interactions-the greatest difficulty lies in the fact that living cells have an unknown number of background processes that may or may not participate in the molecular process of interest, and as a consequence, it is usually impossible to definitively correlate an observation to a well-defined cellular mechanism. One of the experimental methods that can quantitatively capture these interactions is through membrane reconstitution, whereby a lipid bilayer is fabricated to mimic the membrane environment, and the biological components of interest are systematically introduced, without unknown background processes. This configuration allows the extensive use of fluorescence techniques, particularly fluorescence fluctuation spectroscopy and single-molecule fluorescence microscopy. In this review, we describe how the equilibrium diffusion of two proteins, K-Ras4B and the PH domain of Bruton's tyrosine kinase (Btk), on fluid lipid membranes can be used to determine the kinetics of homodimerization reactions.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.551-556
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• 2022

The desalinated water obtained by the water treatment process based on the membrane is attracting a lot of attention as a promising technology that can solve the global water shortage problem. Reverse osmosis membrane-based desalination, one of the most widely used desalination processes, is a technology that desalinates abundant seawater on Earth, thus having great potential in the desalination industry. To improve the performance of the desalination process, it is necessary to understand the reverse osmosis mechanism of the membrane at the atomic/molecular level. In this review, we introduce molecular simulation, which plays an important role in material research today, and the roles of computational simulation at the atomic/molecular level in the development of reverse osmosis membranes.

• Journal of the Korean Magnetic Resonance Society
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• v.2 no.2
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• pp.120-130
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• 1998

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.215-225
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• 2015

Recently, the importance of energy saving and alternative energy is significantly increasing due to energy depletion and the phase change material (PCM) research for saving energy is also actively investigating. In this research, the membrane emulsification using SPG membrane was used to make various microencapsulated phase change material (MPCM) particles which were comprised of $Rubitherms^{(R)}$ (RT-21 and RT-24) core and silica coating. We investigated the pressure of the dispersion phase, the concentration of surfactant, and the ratio of $Rubitherm^{(R)}$ and silica to prepare various MPCM particles. The DSC and TGA were used to examine the heat stability and latent heat properties. Also, PSA, SEM, and optical microscopy were used to confirm the size of $Rubitherm^{(R)}$ particles and the thickness of silica shell. The average of particle size was $7-8{\mu}m$. And, FT-IR was also used to enforce the qualitative analysis. Finally, the MPCM particles obtained from membrane emulsification showed monodispersed size distribution and the heat stability and latent heat were kept up to 80% compared to pure $Rubitherm^{(R)}$. So, it can be effectively used for wallpaper, buildings and interior products for energy saving as PCMs.

• Journal of Applied Biological Chemistry
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• v.59 no.3
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• pp.221-225
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• 2016

Tolaasin is a pore-forming peptide toxin produced by Pseudomonas tolaasii and causes a brown blotch disease by disrupting membrane structures of cultivated mushrooms. The mechanism and characteristics of tolaasin pore formation are not known in detail; however, tolaasin pores have been demonstrated in the artificial lipid bilayer. Since the tolaasin pore appeared less frequently and unstable in lipid bilayer, a mismatch between the length of tolaasin pore and the thickness of lipid membrane had been suggested. Therefore, tolaasin-induced hemolyses were measured by the additions of phospholipids composed of various fatty acids with different carbon numbers. When phosphatidylethanolamines made with two decanoic acids (C10:0, 1,2-didecanoyl-sn-glycero-3-phosphoethanolamine; DDPE), myristic acids (C14:0, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine), and stearic acids (C18:0, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine) were added to the buffer containing RBCs and tolaasin peptides, DDPE facilitated the tolaasin-induced hemolysis while the other two phospholipids showed no effects. At various concentrations of DDPE, the tolaasin-induced hemolysis was stimulated as a dose-dependent manner. The phospholipids composed of mediumchain fatty acids stabilize the tolaasin pore probably by binding between the pore structure and membrane phospholipids and making the membrane thickness thinner around the pore. These results showed that tolaasin molecules make more stable pores in the membrane made with phospholipids composed of medium length fatty acids, suggesting that the length of tolaasin pore is a little shorter than the thickness of RBC membrane.

• Analytical Science and Technology
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• v.9 no.3
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• pp.270-278
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• 1996

Response mechanism for the chloride-selective membrane doped with 5, 10, 15, 20-tetraphenyl(porphyrinato)manganase(III) chloride(Mn(TPP)Cl) in PVC/DOS matrix is proposed by examining the visible spectra of the corresponding optode membrane. The visible spectra of Mn(TPP)Cl-doped membrane placed in aqueous solution show that the chloride ligand is easily replaced with water molecule. When other halogen ions, such as $F^-$, $Br^-$ and $I^-$, are added to the sample solution, they replace the water ligand, exhibiting distinctive change in the Soret band of Mn(TPP). On the other hand, bulky anions, such as SCN and salicylate, do not form a bond with the central metal. These results suggests that the potentiometric response of Mn(TPP)-based membrane results either from the ligand exchange (water with halides) at the central metal or from the counter ion exchange (chlorides with bulky lipophilic anions) around the positively charged porphyrin molecule in membrane phase. It was also noted that both hydration enthalpies of anions and their binding constants to Mn(TPP) play critical role in determining the potentiometric selectivity pattern of the membrane.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.298-303
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• 1999

In order to characterize the effects of heavy metal ions on the microsomal ATPase activities, microsomes were prepared from the roots of tomato plant and the activity of microsomal ATPase was measured by an enzyme-coupled assay. $Hg^{2+}$ inhibited the activity of microsomal ATPase in a dose-dependent manner, while $Gd^{3+}$, $Fe^{3+}$, $La^{3+}$, $Zn^{2+}$, and $Pb^{2+}$ inhibited not only the ATPase activity but also the activities of enzymes used in the assay. However, $Cs^+$ and $Ba^{2+}$ showed no significant effect. $Hg^{2+}$ inhibited the activities of both plasma membrane and vacuolar membrane $H^+-ATPases$. In the dose-response to $Hg^{2+}$, the activities of both microsomal $H^+-ATPases$ were severely inhibited at the concentration of $Hg^{2+}$ above $10\;{\mu}M$ and were completely inhibited at 1 mM $Hg^{2+}$. Apparent Ki values of $Hg^{2+}$ on the inhibitions of plasma membrane and vacuolar membrane $H^+-ATPases$ were $80\;{\mu}M$ and $58\;{\mu}M$, respectively. The $Hg^{2+}$-induced inhibitions were reversible since the addition of dithiothreitol completely reversed the inhibitory effects of $Hg^{2+}$. These results suggest that the inhibitory effects of $Hg^{2+}$ on both plasma, membrane and vacuolar membrane $H^+-ATPases$ are nonselective and reversible.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.130-141
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• 1994

A continuous two-stage membrane (1st-SCMR, MWCO 10,000; 2nd-SCMR, MWCO 5,000) reactor was developed and optimized for the production of fish skin gelatin hydrolysate with different molecular size distribution profiles using trypsin and pronase E. The optimum operating conditions in the 1st-step membrane reactor using trypsin were: temperature, $55^{\circ}C$ ; pH 9.0; enzyme concentration, 0.1 mg/ml; flux, 6.14 ml/min; reaction volume, 600 ml; and the ratio of substrate to trypsin, 100 (w/w). After operating for 1 hr under the above conditions, 79% of total amount of initial gelatin was hydrolysed. In the 2nd-step using pronase E under optimum operating conditions[temperature, $50^{\circ}C$ ; pH 8.0; enzyme concentration, 0.3 mg/ml; flux, 6.14 ml/min; reaction volume, 600 ml; and the ratio of substrate to pronase E, 33 (w/w)], the 1st-step hydrolysate was hydrolysed above 80%. Total enzyme leakages in the 1st-step and 2nd-step membrane reactors were about 11.5% at $55^{\circ}C$ for 5hrs and 9.0% at $50^{\circ}C$ for 4 hrs, respectively. However, there was no apparent correlation between enzyme leakage and substrate hydrolysis. The membrane has a significant effect on activity lose of trypsin and pronase E activity for 1 hr of the membrane reactors operation. The loss of initial activity of enzymes were 34% and 18% in the 1st-step and 2nd-step membrane reactor, whereas were 23% and 10% after operating time 3 hr in the 1st-step and 2nd-step membrane reactor lacking the membrane, respectively. The productivities of 1st-step and 2nd-step membrane reactor for 8 times of volume replacement were 334 mg and 250 mg per mg enzyme, respectively.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1080-1086
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• 1993