• Polymer(Korea)
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• v.39 no.2
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• pp.281-286
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• 2015

UV-cured acrylic copolymer pressure sensitive adhesive (PSA) having different amounts of crosslinking agents were prepared and adhesion properties were investigated. 0.01 wt% of MMT clay was dispersed in 2-ethylhexyl acrylate (2-EHA)/acrylic acid (AA) monomer mixture containing 0, 0.05, 0.1 and 0.3 wt% 1,6-hexandiol diacrylate (HDDA) for crosslinking. It was investigated that the curing behavior and surface chemistry of PSAs were merely affected by the presence of MMT clays. On the other hand, adhesive properties were influenced by the MMT addition; a cohesive failure was restrained due to improved molecular elasticity even in uncrosslinked acrylic PSAs. However, it was also appeared that combination of 0.3 wt% crosslinking agent and MMT loading might result in the damage of adhesion properties of PSAs possibly due to the lack of chain flexibility. In our studies, it is suggested that the 2-EHA/AA PSAs incorporating 0.01 wt% of MMT and crosslinked with 0.05 wt% of HDDA exhibited the balanced adhesion properties without severe cohesive failure during strip.

• Elastomers and Composites
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• v.49 no.3
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• pp.239-244
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• 2014

Reaction between silica and silane coupling agent without solvent was investigated using transmission mode Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Bis[3-(triethoxysilylpropyl) tetrasulfide] (TESPT) was used as a silane coupling agent. After removing the unreacted TESPT, formation of chemical bonds was analyzed using FTIR and content of reacted TESPT was determined using TGA. Content of the coupling agent bonded to silica increased with increase in the coupling agent content, but the oligomers were formed by condensation reaction between coupling agents when the coupling agent was used to excess. In order to identify bonds formed among silica, coupling agent, and rubber, a silica-coupling agent-BR model composite was prepared by reaction of the modified silica with liquid BR of low molecular weight and chemical bond formation of silica-coupling agent-BR was investigated. Unreacted rubber was removed with solvent and analysis was performed using FTIR and TGA. BR was reacted with the coupling agent of the modified silica to form chemical bonds. Polarity of silica surface was strikingly reduced and particle size of silica was increased by chemical bond formation of silica-coupling agent-BR.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.275-275
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• 2013

Formation and characterization of self-assembled monolayers (SAMs) on various surfaces are the essential basis for many other applications, including molecular switches, biosensors, microfluidics, and fundamental studies in surfaces and interfaces. To improve the performance at these applications, it is a key to control the quantity of each molecule in various mixed SAMs on the surface. In this study, using mixed SAM of carbamate-based hydroquinone (HQ)-PhBr and11-mercaptoundecanol, the quantitative mass spectrometric method of mixed SAM was developed based on comparison study with XPS and FT-IR methods. In addition, our method was applied to another mixed SAM of biotinylated PEG alkane thiol and 11-mercaptoundecanol for verification purpose. Time-of-flight secondary mass spectrometry (ToF-SIMS) analysis was performed to identify and quantify each molecule of mixed SAM along with principal component analysis (PCA). Since there is no matrix effect in the X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared (FT-IR) techniques, we compared ToF-SIMS results with XPS and FT-IR results. Because PCA results from ToF-SIMS analysis are well matched with XPS and FT-IR results from both mixed SAMs, we are expecting that our method will be useful to identify and quantify each molecule in various mixed SAMs.

• Food Science of Animal Resources
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• v.34 no.6
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• pp.769-776
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• 2014

The goat placenta was fermented by Bacillus subtilis and the optimal fermentation parameters of strongest antioxidant capacity of peptides were obtained using response surface methodology (RSM). The effects of fermentation time, initial pH value and glucose content on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity of the goat peptides were well fitted to a quadric equation with high determination coefficients. According to the data analysis of design expert, the strongest DPPH radical scavenging capacity value was obtained with the following conditions: content of glucose was 2.23%, initial pH value was 7.00 and fermentation time was 32.15 h. The DPPH radical scavenging capacity commonly referring antioxidant activity showed a concentration dependency and increased with increasing peptide concentration. The effects of temperature and pH were assessed to determine the stability of antioxidant peptides prepared from goat placenta. Antioxidant peptides showed good stabilities when temperature was lower than $70^{\circ}C$. However, the antioxidant peptides lost antioxidant activities rapidly under alkaline and excessive acid condition. Ultrafiltration technique was performed to separate fermentation broth with different Mw (molecular weight). It was found that peptides in the range of < 3 KDa mainly accounted for the antioxidant activities.

• Membrane Journal
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• v.9 no.4
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• pp.202-208
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• 1999

The car washing effluent containing various oils and detergent was treated by ultrafiltration membranes. Dead-end type stirred cell (Amicon 8050) with 10, 30 and lOOk dalton membranes was used to determine permeation and rejection characteristics for the car washing effluent. In case of low molecular weight cut-off membranes, the effect of membrane fouling was weak under the applied pressures. However, the permeation flux for YM100 membrane(look dalton) may be affected by oil layer formation on the membrane surface as well as oil particle plugging for a part of membrane pores due to compressible and deformable oil properties. Oil and particle rejections in the permeates were over 95%, but detergent was passed easily through the membranes. Hence, the permeates containing detergent can be recycled to the system, and may reduce water pollution. Also, the car washing effluent was treated continuously by a capillary type ultrafiltration membrane of MWCO 50k dalton. The experimental data were fitted suitably to the cake filtration model.

• The Journal of Pediatrics of Korean Medicine
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• v.21 no.1
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• pp.139-154
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• 2007

Objectives : The author intended to investigate Seonbangpaedoktang (SBPT) significantly affect in vivo and in vitro mucin secretion from airway epithelial cells. Methods : In vivo experiment, the author induced hypersecretion of airway mucin, hyperplasia of tracheal goblet cells and the increase in intraepithelial mucosubstances. Effects of orally-administered SBPT during 1 week on in vivo mucin secretion and hyperplasia of tracheal goblet cells were assessed. For in vitro experiment, confluent hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled and chased in the presence of SBPT to assess the effect of the agent on 3H-mucin secretion. Total elution profiles of control spent media and treatment sample through Sepharose CL-4B column were analysed. Possible cytotoxicity of the agent was assessed by measuring LDH release. Also, the effect of SBPT on contractility of isolated tracheal smooth muscle was investigated. Results : SBPT inhibited hypersecretion of in vivo mucin and inhibited the increase of number of goblet cells ; SBPT did not affect in vitro mucin secretion and the secretion of the other releasable glycoproteins with less molecular weight than mucin from cultured HTSE cells, without significant effect on LDH release; SBPT did not affect Ach-induced contraction of isolated tracheal smooth muscle. Conclusions : SBPT can inihibit hypersecretion of in vivo mucin and the author suggest that the effect SBPT with their components should investigate further.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.48.1-48.1
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• 2009

In recent years, many candidates for extra-solar planet have been discovered from various measurement techniques. Fueled by such discoveries, new space missions for direct detection of earth-like planets have been proposed and actively studied. TPF instrument is a fair example of such scientific endeavors. One of the many technical problems that space missions such as TPF would need to solve is deconvolution of the collapsed (i.e. spatially and temporally) spectral signal arriving at the detector surface and the deconvolution computation may fall into a local minimum solution, instead of the global minimum solution, in the optimization process, yielding mis-interpretation of the spectral signal from the potential earth-like planets. To this extend, observational and theoretical understanding on the spectral bio-signal from the Earth serves as the key reference datum for the accurate interpretation of the planetary bio-signatures from other star systems. In this study, we present ray tracing computational model for the on-going simulation study on the Earth bio-signatures. A multi-layered atmospheric model and sea ice variation model were added to the existing target Earth model and a hypothetical space instrument (called AmonRa) observed the spectral bio-signals of the model Earth from the L1 halo orbit. The resulting spectrums of the Earth show well known "red-edge" spectrums as well as key molecular absorption lines important to harbor life forms. The model details, computational process and the resulting bio-signatures are presented together with implications to the future study direction.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1282-1292
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• 2018

The exopolysaccharide (EPS) produced by Bacillus amyloliquefaciens GSBa-1 was isolated and purified by ethanol precipitation, and DEAE-cellulose and Sepharose CL-6B chromatographies. The molecular mass of the purified EPS was determined to be 54 kDa. Monosaccharide analysis showed that the EPS was composed of predominantly glucose, and it was further confirmed by NMR spectroscopy to be ${\alpha}-glucan$ that consisted of a trisaccharide repeating unit with possible presence of two ${\alpha}-(1{\rightarrow}3)$ and one ${\alpha}-(1{\rightarrow}6)$ glucosidic linkages. Microstructural analysis showed that the EPS appeared as ellipsoid or globose with a smooth surface. The EPS had a degradation temperature at $240^{\circ}C$. Furthermore, the EPS had strong DPPH and hydroxyl radical scavenging activities, and moderate superoxidant anion scavenging and metal ion-chelating activities. This is the first characterization of a glucan produced by B. amyloliquefaciens with strong antioxidant activity. The results of this study suggest the potential of the EPS from B. amyloliquefaciens GSBa-1 to serve as a natural antioxidant for application in functional products.

• Journal of the Korean Chemical Society
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• v.9 no.4
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• pp.185-189
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• 1965

Korean acid clays and silica gel were put into action on benzene solution of dye, such as aniline yellow, o-nitro aniline and oil orange, and then the adsorptivity of dye in nonaqueous solution was measured, with the result that adsorptivity was greater with silica than acid clays and it had no relation to acidity. And when chemical compounds, such as amine, alcohol, halogen derivative, were added to each dye solution by 10%(in volume), the change of the adsorptivity of dye by solid acid(that is, the interfered adsorption rate) decreased in order of amine > alcohol > halogen derivative, and in homologue the smaller the molecular weight, the larger was the effect. So adsorption in nonaqueous solution was a selective adsorption of chemical compounds which contained negative groups such as amine and hydroxyl radicals, and it had no relation to surface tension and showed inverted phenomenon of Traube series. It is guessed that the inverted phenomenon (the interfered adsorption phenomenon) was due to the polar chemical adsorption between active $SiO_2$ which was an origin of solid acid and the adsorbed substances, considering that the order of inversion was nearly in accord with dipole moment of added solvents. The results of this study led to find adsorption mechanism and inverted phenomenon of Traube series in nonaqueous solution.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3676-3680
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• 2012

An Epstein-Barr virus (EBV)-based plasmid contains the EBV nuclear antigen 1 (EBNA1) gene and EBV replication origin (oriP) sequence. Since EBNA1 (the only EBV-encoded protein) is combined with oriP, it is replicated simultaneously with chromosomal DNA in human, primate, and canine cells and is faithfully segregated at a stable copy number upon cell division. Consequently, it can be used to stably express gene inserts over a prolonged time in target cells. We have previously shown that the polyamidoamine (PAMAM) dendrimer can be surface-modified with L-arginine. Arginine is present at a high frequency in the transactivator of transcription (Tat) sequences of human immunodeficiency virus (HIV). It presents high membrane permeability and permits effective transfer of DNA inside the cells. In this study, we constructed two kinds of recombinant DNA by inserting the luciferase gene and enhanced green fluorescence protein (eGFP) gene as reporter genes into the pCEP4 plasmid vector. We measured dynamic light scattering (DLS) and zeta potential after preparing PAMAM-based cationic polymer/EBV-based plasmid complexes. We performed transfection of HEK 293 cell lines with the polyplexes, and monitored luciferase activity and green fluorescence protein (GFP) expression. Our results show that PAMAM-based cationic polymer/EBV plasmid complexes provide enhanced and sustained gene expression.