• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.3
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• pp.163-174
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• 2014

The objective of this study is to prepare an artificial extracellular matrix (ECM) for cell culture by using polymer hydrogels. The polymer used is a cytocompatible water-soluble phospholipid polymer: poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-n-butyl methacrylate-p-nitrophenyloxycarbonyl poly(ethylene oxide) methacrylate (MEONP)] (PMBN). The hydrogels are prepared using a cross-linking reaction between PMBN and diamine compounds, which can easily react to the MEONP moiety under mild conditions. The most favorable diamine is the bis(3-aminopropyl) poly(ethylene oxide) (APEO). The effects of cross-linking density and the chemical structure of cross-linking molecules on the mechanical properties of the hydrogel are evaluated. The storage modulus of the hydrogel is tailored by tuning the PMBN concentration and the MEONP/amino group ratio. The porous structure of the hydrogel networks depends not only on these parameters but also on the reaction temperature. We prepare a hydrogel with $40-50{\mu}m$ diameter pores and more than 90 wt% swelling. The permeation of proteins through the hydrogel increases dramatically with an increase in pore size. To induce cell adhesion, the cell-attaching oligopeptide, RGDS, is immobilized onto the hydrogel using MEONP residue. Bovine pulmonary artery endothelial cells (BPAECs) are cultured on the hydrogel matrix and are able to migrate into the artificial matrix. Hence, the RGDS-modified PMBN hydrogel matrix with cross-linked APEO functions as an artificial ECM for growing cells for applications in tissue engineering.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.7
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• pp.1065-1072
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• 2000

The molecular areas and the interfacial tension behavior of ten nonionic surfactants, i.e., Span 20 and Tween 20, 40, 60. 80, 21, 61, 81, 65, & 85 are tested to assay their effects on the wetting and liquid retention properties of hydrophilic and hydrophobic fibrous materials. The molecular areas at water/air interface are derived from Gibbs’adsorption equations. The following conclusions are drawn from the results: 1) Span 20 is efficient in lowering the interfacial tension and effective in adsorption at the water/air interface, resulting in the low interfacial tension at critical micelle concentration (${\gamma}$$_{CMC}$) and a small molecular area($\omega$), 2) when the hydrophiles of the surfactants are constant, $\omega$’s increase as hydrophobe carbon numbers of the surfactants increase, 3) when the hydrophobes are constant, ${\gamma}$$_{CMC}$’s and $\omega$’s increase as the hydrophile ethylene oxide units increase, indicating effectiveness and efficiency is parallel in this case, 4) the ethylene oxide unit length as a hydrophile has greater influence on u than the hydrophobe chain length.han the hydrophobe chain length.gth.

• Journal of the Korean Wood Science and Technology
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• v.44 no.4
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• pp.526-538
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• 2016

Fumigants are used worldwide for control of biological agents that damage wooden cultural property. To establish a policy for fumigant use, biological evaluation of insects and microorganisms considering many factors is required. This study was performed to evaluate biological sensitivity and wood penetration of three fumigants applied for control of biological agents that damage wooden cultural properties in Korea. Among these, methyl bromide and ethylene oxide can control insects and fungi when exposed directly. However, they were unable to completely control biological agents within deeper parts of wood. Ethanedinitrile, which was developed as an alternative fumigant, exhibited outstanding wood penetration and biocidal efficacy. Further research involving various environmental conditions is warranted.

• Textile Coloration and Finishing
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• v.23 no.2
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• pp.140-145
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• 2011

The effects of nonionic surfactant solutions of 0.1g/dL on detergency and liquid wetting/retention properties of soiled polyester/cotton(65/35) cloth were studied. Soiled polyester/cotton(65/35) cloth (EMPA 104) and 10 different nonionic surfactants (Span 20, Tween 20, 40, 60, 80, 21, 61, 81, 65, 85) were used in the study. The water retention and liquid retention capacity values of soiled cloth were decreased compared with those of unsoiled cloth. The wetting and water retention of soiled cloth improved with addition of surfactants, whereas water retention ratio(W/H) values didnot change markedly. Generally surfactants with low surface tension and high HLB (Hydrophile-lipophile balance) were more effective in improving the wetting/retention properties of soiled cloth. Nonionic surfactants having high ethylene oxide contents of 20 moles; i.e., Tween 20, 40, 60 & 80, showed better detergency than low ethylene oxide contents of 4 moles; i.e., Tween 21, 61 & 81. As HLB values of surfactants and $cos{\theta}$ of the soiled cloth increase, the detergency values of soiled cloth increased.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2655-2660
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• 2009

A breed of cattle, i.e., Korean cattle (Hanwoo), was identified based on the DNA mobilities of their microsatellites (MSs) by capillary gel electrophoresis (CGE) with a laser-induced fluorescence (LIF) detector. The MS markers were used for the accurate identification of species-specific genes. The DNA mobilities of the MS markers of Hanwoo and Holstein were measured using a CGE system with a fused-silica capillary (inner diameter of 75 ${\mu}m$, outer diameter of 365 ${\mu}m$, and total length of 50 cm). The capillary was dynamically coated with 1.0% (w/v) polyvinylpyrrolidone ($M_r$ = 1,000,000) and then filled with a mixture of 1.3% (w/v) poly(ethylene oxide) ($M_r$ = 600,000) and 1.9% (w/v) poly(ethylene oxide) (Mr = 8,000,000) as a sieving gel matrix. The species-specific genes of Hanwoo and Holstein were clearly distinguished within 33 min. This CGE assay technique is expected to be a useful analytical method for the fast and accurate identification of breeds of cattle.

• Macromolecular Research
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• v.11 no.5
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• pp.341-346
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• 2003

A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.205-208
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• 1994

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. PEO-$LiClO_4$ electrolyte with plasticizer is very unstable. Passivation phenomena in polymer electrolyte cell was described by the SPL model. The time dependance of the impedance indicates that a passivation layer grows rapidly on the Li surface. However, the growing of passivation layer on the Li surface can be restrained by addition of zeolite to the PEO electrolyte. It suggested that addition of zeoliteto to the PEO-$LiClO_4$ electrolyte effectively controls the formation of a passivation layer on Li electrode.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.123-128
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• 1989

Calorimetric study in conjunction with Fourier-transform infrared (FTIR) spectroscopic study was carried out on the blends of poly(ethylene oxide) (PEO) with isotactic, atactic and syndiotactic poly(methyl methacrylate) (i-, a-, and s-PMMA). From the differential scanning calorimetric (DSC) measurements, the three types of blends show a depression of the melting temperatures. This indicates that PEO is compatible with i-, a-, and s-PMMA. But the largest melting point depressions of PEO are always found in the blends with s-PMMA. For PEO/a-PMMA and PEO/s-PMMA, the degree of crystallinity as a function of composition deviates substantially from that of the ideal blend in which no interaction between the components exists. The FTIR spectra of all three types of blends are recorded. In order to observe the microstructural changes of PEO in blends, we analyzed the spectra using digital weighted subtraction and addition techniques. It was concluded that the microstructures of PEO are strongly perturbed by the PMMA's. Among these blends PEO microstructure in PEO/s-PMMA blends is most greatly influenced. It indicates that the blending is most preferred with s-PMMA than a- and i-PMMA. It can be explained on the basis of the molecular structure of PMMA's.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.962-967
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• 1998

Block copolymers consisting of poly(rbenzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part were synthesized and characterized. Polymeric micelles of the block copolymers (abbreviated GEG) were prepared by a dialysis method. The GEG block copolymers were associated in water to form polymeric micelles, and the critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymers. Transmission electron microscopy (TEM) observations revealed polymeric micelles of spherical shapes. From dynamic light scattering (DLS) study, sizes of polymeric micelles of GEG-1, GEG-2, and GEG-3 copolymer were 106.5±59.2 nm, 79.4±46.0 nm, and 37.9±13.3 nm, respectively. The drug loading contents of GEG-1, GEG-2 and GEG-3 polymeric micelles were 12.6, 11.9, and 11.0 wt %, respectively. These results indicated that the drugloading contents were dependent on PBLG chain length in the copolymer; the longer the PBLG chain length, the more the drug-loading contents. Release of norfloxacin (NFX) from the nanoparticles was slower in higher loading contents of NFX than in lower loading contents due to the hydrophobic interaction between PBLG core and NFX.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.283-287
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• 1986

E.O. and gamma irradiation treatment on the sterilization of ground samples of 5 different types of spices(red and black pepper, onion, garlic and ginger) were investigated. Populations of mesophilic bacteria, mesophilic spores, acid tolerant bacteria and fungi in various samples were $10^4-10^6/g,\;10^3-10^5/g,\;10^3-10^5/g\;and\;10^3-10^4/g$, respectively. Coliforms and osmophilic molds were found only in red and black pepper as $10^3-10^4/g$. A radiation dose of 5 to 7 kGy proved sufficient to redure the viable cell count of the total bacteria and fungi to the level of $10^3/g$ and they were sterilized completely by radiation dose of 10 kGy or more. Coliforms, mesophilic spores and acid tolerant bacteria were sterilized at 5,7 and 10 kGy, respectively. In the mean time $D_{10}$ values of each spices ranged from 1.38 to 2.88 kGy. Comparison of E.O. and gamma irradiation treatment showed that E.O. treatment was less effective than radiation in controlling microbial contamination in spices.