• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1457-1458
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• 2009

The fundamental parameters controlling ink-jet printing liquids are the viscosity and surface energy. The wetting contact angle determines the spread of a liquid drop on the surface and depends on the relative surface energy. The characteristics of silver ink-jet printing were studied with control of surface energy and head temperature. Polyethylene terephthalate(PET) film and Si-wafer(ptype) were used as substrates and atmospheric plasma was treated to control the surface energy. With silver ink, the hydrophilic surface treatment could reduce the radius of droplets due to the hydrophobic nature of silver ink.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.87-92
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• 1996

This study describes a stable and simple method for the measurement of cholesteryl ester transfer protein(CETP) activities using reconstituted HDL and LDL as substrates. Apolipoproteins (apo) A-I and -B were purified from hog plasma by a new strategy without ultracentrifugation and delipidation. a simple two-step column chromatography was administered. In the first step of phenyl-sepharose CL-4B column chro-matography, hydrophobic plasma proteins were isolated. The most hydrophobic proteins bound to the column appeared to be A-I and apo-B. Contaminat proteins were efficiently eliminated from the sample by washing the column with 0.3M NaCI containing buffer after loading the plasma on the column. Two pure proteins showing each single band on SDS-PSGE of apo A-I and apo-B were individually obtained by a subsequent gel filtration column chromatography(Sephadex G-200). This two-step purification was simple and inexpensive compared to the ultracentrifugation and/or delipidation method that are most commonly used. Reconstituted hight-density lipoproteins(HDL) and low-density lipoproteins(LDL) were prepared using the purified apo A-I and-B, respectively. When these artificially prepared HDL and LDL were used in the assays for CETP as the cholesteryl ester(CE) donor and acceptor respectively, the specific transfer of CE increased up to two fold compared to that used the native HSL and LDL.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.99-102
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• 2005

Organic solvents are widely used in biotransformation systems. There are many efforts to reduce the consumption of organic solvents because of their toxicity to the environment and human health. In recent years, several groups have started to explore novel organic solvents called room temperature ionic liquids in order to substitute conventional organic solvents. In this work, lipase-catalyzed transesterification in several uni- and bi-phasic systems was studied. Two representative hydrophobic ionic liquids based on 1-butyl-3-methylimidazolum coupled with hexafluorophosphate ([BMIM][$PF_6$]) and bis[{trifluoromethylsulfonyl} imide] ([BMIM] [$Tf_{2}N$]) were employed as reaction media for the transesterification of n-butanol. The commercial lipase, Novozym 435, was used for the transesterification reaction with vinyl acetate as an acyl donor. The conversion yield was increased around $10\%$ in a water/[BMIM][$Tf_{2}N$] bi-phasic system compared with that in a water/hexane system. A higher distribution of substrates into the water phase is believed to enhance the conversion yield in a water/[BMIM][$Tf_{2}N$] system. Partition coefficients of the substrates in the water/[BMIM][$Tf_{2}N$] bi-phasic system were higher than three times that found in the water/hexane system, while n-butyl acetate showed a similar distribution in both systems. Thus, RTILs appear to be a promising substitute of organic solvents in some biotransformation systems.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1047-1052
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• 2006

A bile salt hydrolase (BSH) was purified from Lactobacillus plantarum CK 102 and its enzymatic properties were characterized. This enzyme was successfully purified using ion-exchange chromatography with Q-Excellose and hydrophobic interaction chromatography with Butyl-Excellose. The purified enzyme showed a single protein band of 37 kDa by SDS-polyacrylamide gel electrophoresis, which was similar to the molecular weight of known BSHs. The amino acid sequence of GLGLPGDLSSMSR, determined by MALDI-TOF, was identical to that of BSH of L. plantarum WCFS1. Although this BSH hydrolyzed all of the six major human bile salts, glycine-conjugated bile acid was the best substrate, based on its specificity and $K_{m}$ value. Among the various substrates, the purified enzyme maximally hydrolyzed glycocholate with apparent $K_{m}$ and $V_{max}$ values of 0.5 mM and 94 nmol/min/mg, respectively. The optimal pH of the enzyme ranged from 5.8 to 6.3. This enzyme was strongly inhibited by thiol enzyme inhibitors such as iodoacetate and periodic acid.

• Reproductive and Developmental Biology
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• v.34 no.1
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• pp.7-13
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• 2010

The binding affinity constants ($p(Od)_{50}$) and molecular docking scores (OS) between porcine odorant binding proteins pOBP (1HQP) and pPBP (1GM6) as receptor and a series of tetrahydrofuran-2-yl (A & B) analogues as substrate, and their interactions were discussed quantitatively using three-dimensional quantitative structure-activity relationship (30-QSAR) models. The statistical qualities of the optimized CoMF A models for pOBP were better than those of the CoMSIA models. The binding affinity constants and OS between substrate and receptor molecules were dependent upon steric and hydrophobic interaction. The DS constants of the substrates into the binding site of OBP (1HQP) were bigger than those of PBP (1GM6). The resulting contour maps produced by the optimized CoMFA model were used to identify the structural features relevant to the binding affinity in binding site of pOBP.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.743-746
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• 2003

We have successfully used hydrophobic direct-wafer bonding, along with H-induced layer splitting of Ge, to transfer 700nm think, single-crystal Ge films to Si substrates. Optical and electrical properties have been also observed on these samples. Triple-junction solar cell structures gown on these Ge/Si heterostructure templates show comparable photoluminescence intensity and minority carrier lifetime to a control structure grown on bulk Ge. When heavily doped p$^{+}$Ge/p$^{+}$Si wafer bonded heterostructures were bonded, ohmic interfacial properties with less than 0.3Ω$\textrm{cm}^2$ specific resistance were observed indicating low loss thermal emission and tunneling processes over and through the potential barrier. Current-voltage (I-V) characteristics in p$^{+}$Ge/pSi structures show rectifying properties for room temperature bonded structures. After annealing at 40$0^{\circ}C$, the potential barrier was reduced and the barrier height no longer blocks current flow under bias. From these observations, interfacial atomic bonding structures of hydrophobically wafer bonded Ge/Si heterostructures are suggested.ested.

• BMB Reports
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• v.36 no.2
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• pp.149-153
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• 2003

The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiocholine (BuTch) or acetylthiocholine (AcTch) substrates, and measured at 412 nm. Dibucaine, a quaternary ammonium compound, inhibited SChE to a minimum within 2 min in a reversible manner. The inhibition was very potent. It had an $IC_{50}$ of $5.3\;{\mu}M$ with BuTch or $3.8\;{\mu}M$ with AcTch. The inhibition was competitive with respect to BuTch with a $K_i$ of $1.3\;{\mu}M$ and a linear-mixed type (competitive/noncompetitive) with respect to AcTch with inhibition constants, $K_i$ and $K_I$ of 0.66 and $2.5\;{\mu}M$, respectively. Dibucaine possesses a butoxy side chain that is similar to the butryl group of BuTch and longer by an ethylene group from AcTch. This may account for the difference in inhibition behavior. It may also suggest the existence of an additional binding site, other than the anionic binding site, and of a hydrophobic nature.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.167.1-167.1
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• 2014

We report a facile method to fabricate superhydrophobic, transparent and conductive film using multi-walled carbon nanotubes (MWCNTs) which are coated by polydimethylsiloxane (PDMS). In order to prepare a film, PDMS coated MWCNTs were dispersed in solvents and the solution was drop-casted on substrates. It was demonstrated that the PDMS coating enhanced the dispersion of MWCNTs in diverse solvents such as dimethyl formamide(DMF) and acetone without the use of acids or surfactants, which are the common methods. In the case of DMF solvent, dispersion of MWCNT was improved by 40 % upon PDMS-coating of MWCNT. Enhanced dispersion of MWCNTs made it possible to fabricate transparent and conductive film homogeneously on the substrate and PDMS-coating on MWCNTs also made the surface hydrophobic. We can fabricate a uniform and multifunctional MWCNT film (transparent, conductive, superhydrophobic and flexible) which is applicable on large area without any physical damage and expensive equipment.

• Korean Journal of Materials Research
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• v.25 no.11
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• pp.622-629
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• 2015

Cu circuits were successfully fabricated on flexible PET(polyethylene terephthalate) substrates using wettability difference and electroless plating without an etching process. The wettability of Cu plating solution on PET was controlled by oxygen plasma treatment and $SiO_x$-DLC(silicon oxide containing diamond like carbon) coating by HMDSO(hexamethyldisiloxane) plasma. With an increase of the height of the nanostructures on the PET surface with the oxygen plasma treatment time, the wettability difference between the hydrophilicity and hydrophobicity increased, which allowed the etchless formation of a Cu pattern with high peel strength by selective Cu plating. When the height of the nanostructure was more than 1400 nm (60 min oxygen plasma treatment), the reduction of the critical impalement pressure with the decreasing density of the nanostructure caused the precipitation of copper in the hydrophobic region.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.496-496
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• 2011

A very simple and cost-effective method for fabrication of SiOx-incorporated diamond-like carbon (DLC) thin films at a preparation temperature of less than $200^{\circ}C$ was developed. Since DLC coating can be prepared not under vacuum but atmospheric conditions without any carrier gas flow, not only wafers but also powderic substrates can be used for DLC coating. Formation of DLC coating could result in appearance of superhydrophobic behaviors, which was sustained in a wide range of pH (1~14). DLC-coated surfaces selectively interacted with toluene in a toluene/water mixture. These results imply that our preparation method of the DLC coating can be useful in many application fields such as creating self-cleaning surfaces, and water and air purification filters.