• Tribology and Lubricants
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• v.21 no.3
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• pp.107-113
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• 2005

Micro/nano adhesion and friction properties of self-assembled monolayers (SAMs) with different head- and end-group were experimentally studied according to the coating methods. Various kinds of SAM having different spacer chains (C10 and C18), head-group and end-group were deposited onto Si-wafer by dipping and chemical vapour deposition (CVD) methods under atmospheric pressure, where the deposited SAM resulted in the hydrophobic nature. The adhesion and friction properties between tip and SAM surfaces under nano scale applied load were measured using an atomic force microscope (AFM) and also those under micro scale applied load were measured using a ball-on-flat type micro-tribotester. Surface roughness and water contact angles were measured with SPM (scanning probe microscope) and contact anglemeter respectively. Results showed that water contact angles of SAMs with the end-group of fluorine show higher relatively than those of hydrogen. SAMs with the end-group of fluorine show lower nano-adhesion but higher micro/nanofriction than those with hydrogen. Water contact angles of SAMs coated by CVD method show high values compared to those by dipping method. SAMs coated by CVD method show the increase of nano-adhesion but the decrease of nano-friction. Nano-adhesion and friction mechanism of SAMs with different end-group was proposed in a view of size of fluorocarbon molecule.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1668-1675
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• 2004

The effect of pH on surface hydrophobicity, sulfhydryl group, infrared spectrum, SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) pattern and enthalpy was investigated in recovered protein from mackerel and frozen blackspotted croaker by alkaline processing. Hydrophobic residue in myofibrillar protein exposed to the surface of protein, and hydrophobic interaction were the highest around 6$0^{\circ}C$. The surface hydrophobicity was different between myofibrillar protein and myofibrillar protein including sarcoplasmic protein (recovered protein). The peak at 1636 c $m^{-l}$ was increased with pH, and the recovered protein was unfolded in alkali pH. Difference of surface and total sulfhydryl group at pH 7.0 and 10 was comparative high, and decrease of surface sulfhydryl group indicated formation of S-S bonds. Mackerel and frozen blackspotted croaker in alkaline pH showed bands of polymerized myosin heavy chain on SDS-PAGE pattern. The transition temperatures of recovered protein were 33.1, 44.3 and 65.5$^{\circ}C$. Gelation of recovered protein from alkali processing was estimated by increase of $\beta$-sheet structure by pH treatment, S-S bonds by oxidation of surface sulfhydryl group in heating, polymerization of myosin heavy chain in order.r.

• Textile Coloration and Finishing
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• v.20 no.2
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• pp.59-65
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• 2008

The tannin acid and the enzymes have been used in order to improve the ruggedness in laundry and the absorption of dyes and pigments in the textile industry for several years. The enzyme processing on the protein fiber minimizes the damage of the entire fiber and improves the dyeability by effectively modifying only the hydrophobic surface. This study tried out the structural observation by applying the Castanea crenata sieb. et. zucc. containing abundant tannin to the hair dyeing as the natural dyeing pigment along with Protease of Rhizopus sp. The dyeability was improved as compared to the dyeing using only the synthetic tanning and iron mordant. When the depth of pigment was higher in accordance with the surface observation, the enzyme dissolution had impact on dyeing and so the keratin layer on the hair surface. Accordingly, it was found that the appropriate depth was between 0.01 and 0.03%. It was estimated that 0.1% protease would treated within 30min. Consequently, it would cause the good reaction with the functional group of tannin pigment.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.795-800
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• 1994

The detergencies of these new functional anionic surfactants, sodium monoglycerol ${\alpha}$-sulfonated alkanoates, were investigated and compared with those of two commercial surfactants, that is, sodium ${\alpha}$-sulfonated alkanoic acid methyl ester and sodium alkyl benzene sulfonate. According to the variation of the hydrophobic alkyl chain length, the order of detergency was shown to be $C_{16}$>$C_{18}$>$C_{14}$>$C_{12}$. From the comparision experiment for the detergency and the various fundamental properties of two other surfactants, it was found that sodium monoglycerol ${\alpha}$-sulfonated hexadecanonate has the most outstanding characteristics of detergency. Possibly this result shows light on its industrial application as a nonpolluting detergent.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.801-807
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• 1994

Lactose substituted styrene monomer, N-(p-vinylbenzyl)-D-lactonamide(VLA) was prepared by coupling the lactose lactone with p-vinylbenzylamine. The carboxyl group of biotin was activated with N-hydroxysuccinimide in the presence of N, N'-dicyclohexylcarbodiimide. Subsquently, biotin substituted styrene monomer, N-(p-vinylbenzyl)-biotinamide(VBA) was prepared by amidation of the activated biotin with p-vinylbenzylamine. Poly(vinylbenzylactonamide-co-vinylbenzylbiotinamide), p(VLA-co-VBA) were synthesized through radical polymerization from the synthetic monomers(VLA-VBA) by using various mole ratio. The percentages of yield were 67~71%. The copolymers were found amphlphilic which had hydrophilic lactose, hydrophobic vinylbenzyl and biotin site within the structure. IR and $^{13}C-NMR$ analysis on the monomers and copolymer were carried out.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.294-300
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• 2010

The Iro protein is a member of the HiPIP family with the [$Fe_4S_4$] cluster for electron transfer. Many reports proposed that the conserved aromatic residues might be responsible for the stability of the iron-sulfur cluster in HiPIP. In this study, Tyr10 was found to be a critical residue for the stability of the [$Fe_4S_4$] cluster, according to site-directed mutagenesis results. Tyr10, Phe26, and Phe48 were essential for the stability of the [$Fe_4S_4$] cluster under acidic condition. Trp44 was not involved in the stability of the [$Fe_4S_4$] cluster. Molecular structure modeling for the mutant Tyr10 proteins revealed that the aromatic group of Tyr10 may form a hydrophobic barrier to protect the [$Fe_4S_4$] cluster from solvent.

• Journal of Environmental Science International
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• v.28 no.2
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• pp.183-189
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• 2019

Curcumin ($C_{21}H_{20}O_6$) is a hydrophobic polyphenol found in turmeric. Although curcumin has been used as a natural medicine, its major limitation is related to poor absorption from the gut. Therefore, we developed a method for preparation of Curcumin Nanospheres (CN) to improve the aqueous-phase solubility of curcumin and investigate the functional role of CN in promoting feed efficiency and odor reduction in mice. CN showed inhibitory effects on actate dehydrogenase (LDH) cytotoxicity induced by ecotoxic substance toluene in gut epithelial HCT116 cells. In addition, the weights of internal organs (liver, heart, kidneys, and spleen) and the levels of serum Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), and LDH did not show significant differences between mice administered oral CN for two weeks and compared to the control group. Interestingly, CN not only reduced hydrogen sulfide ($H_2S$) and ammonia ($NH_3$) levels and fecal odor, but also improved feed efficiency in mice. These results demonstrate that oral nano-delivery of anti-ecotoxicological CN is a functional system to deliver curcumin to the gut to improve feed efficiency and reduce fecal odor in mice.

• 한국해양학회지
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• v.29 no.2
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• pp.171-182
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• 1994

Dissolved free amino acid (DFAA) dissolved hydrolyzable amino acid (DHAA) and D/L amino acid racemic ratio in the dissolved organic compounds were studied to investigate the biogeochemical characteristics of dissolved organic compound in the Yellow Sea. Concentration of total DFAA ranged from 0.06 uM to 0.26 uM in the study area. DFAA composition showed that aspiratae, glutamate, serine, glycine and alanine were predominant. According to characteristics of functional group of amino acid, these belonged to hydroponic group. C-18 short column cartridge (Sep-Pak) activated by methanol was used to extract organic macromolecules in the seawater. In operational scheme, macromolecules were divided into two fractions. Geomacromolecule fraction eluted with 50% methanol was used to extract organic macromolecules in the seawater. In operational scheme, macromolecules were divided into two fractions. Geomacromolecule fraction eluted with 50% methanol was moderately hydrophilic and showed characteristics of humic substance in the seawater. Biomacromolecule fraction eluted with 100% methanol was hydrophobic and most abundant in the surface seawater samples. DHAA was much higher than DFAA in this study area. DHAA ranged from 2.05 uM to 6.19 uM in the B-fraction and from 8.13 uM to 24.46 uM in the G-fraction. DHAA was higher in the surface water than in the bottom water where the vertical stratification developed well. The result of HPLC analysis of D/L amino acid showed that low racemic ratio was found in the B-fraction. It implies that the B-fraction is relatively younger than the G-fraction and freshly derived from biosphere.

• Molecules and Cells
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• v.39 no.3
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• pp.217-228
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• 2016

To generate a biobetter that has improved therapeutic activity, we constructed scFv libraries via random mutagenesis of several residues of CDR-H3 and -L3 of hu4D5. The scFv clones were isolated from the phage display libraries by stringent panning, and their antiproliferative activity against HER2-positive cancer cells was evaluated as a primary selection criterion. Consequently, we selected AH06 as a biobetter antibody that had a 7.2-fold increase in anti-proliferative activity ($IC_{50}$: 0.81 nM) against the gastric cancer cell line NCI-N87 and a 7.4-fold increase in binding affinity ($K_D$: 60 pM) to HER2 compared to hu4D5. The binding energy calculation and molecular modeling suggest that the substitution of residues of CDR-H3 to W98, F100c, A101 and L102 could stabilize binding of the antibody to HER2 and there could be direct hydrophobic interactions between the aromatic ring of W98 and the aliphatic group of I613 within HER2 domain IV as well as the heavy and light chain hydrophobic interactions by residues F100c, A101 and L102 of CDR-H3. Therefore, we speculate that two such interactions were exerted by the residues W98 and F100c. A101 and L102 may have a synergistic effect on the increase in the binding affinity to HER2. AH06 specifically binds to domain IV of HER2, and it decreased the phosphorylation level of HER2 and AKT. Above all, it highly increased the overall level of p27 compared to hu4D5 in the gastric cancer cell line NCIN82, suggesting that AH06 could potentially be a more efficient therapeutic agent than hu4D5.

• Polymer(Korea)
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• v.36 no.6
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• pp.795-802
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• 2012

Surface modification of a hydrophobic acrylic polymer film has been performed through simple chemical treatment to give a reactive surface. 2-Triphenylstannylthioethyl acrylate was polymerized under UV-illumination with various contents of a comonomer. When the polymer film was treated with fluoride ion, thiol functional group (SH) was generated on the film surface, which was observed through infrared absorption spectroscopy. The surface was functionalized by thiol addition reaction to acrylic chromophores. The SH content on the surface was controlled with a comonomer, tris(hydroxymethyl)ethane triacrylate, and examined with UV-Vis absorbance of the chromophore attached film. Similarly, a polymer film from 2-tributylstannylthioethyl acrylate was prepared. Destannylation from the triphenylstannyl and tributylstannyl surface completed after 30 and 5 min, respectively. The SH-exposed surface was modified with an isocyanate attached chromophore within 10 min, while acrylic chromophore required 24 h.