• Journal of Embryo Transfer
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• v.9 no.2
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• pp.173-180
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• 1994

The present experirnents on cryopreservation were carried out to investigate effect of solution toxicity, equilibration time and cell stages on the post-thaw survival of mouse morulae and blastocyst embryos cryopreserved by vitrification in EFS solution. The mouse embryos were exposed to the EFS solution in one step at room temperature, kept in the EFS solution during different period for toxicity test, vitrified in liquid nitrogen and thawed rapidly. After the mouse morulae embryos were exposed to EFS solution for 2 and 5 ruin. at room temperature and then they were washed in 0.5 M sucrose solution and basal mediurn(D-PBS + 10% FCS), they were cultured to examined cryoprotectant toxicity induced injury during exposure, most of embryos developed to expanded blastocysts(100 and 90.0%). However, when the exposure time was extended to 10 and 20 min, these development rates dropped dramatically in 10 ruin. (75.0%) and 20 ruin. (4.5%), respectively. When the compacted morulae were vitrified in EFS solution after equilibration for 2 and 5 min, the embryos have developed to normal blastocyst following thawing, washing and culture processes was 89.3 and 89.6%. However, when the exposure time was expanded to 10 ruin, this survival rate dropped to 68.8%. When the blastocyst were vitrified in EFS solution after equilibration for 2, 5 and 10 minutes, the survival rate of embryos which developed to normal blastocyst following thawing and culture processing were 58.5, 46.7 and 22.4%, respectively. The optimal time of equilibration of mouse morula and blastocysts in EFS solution seemed o be 2 and 5 ruin.

• Analytical Science and Technology
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• v.29 no.5
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• pp.225-233
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• 2016

The chemical engrafting of polymers on particle surface, plays an important role on selective partitioning of micro/nano-particles in the separated layers of liquid media, such as aqueous two phase systems (ATPSs). Three polymers, dextran, poly (ethylene glycol) and albumin were chosen and chemically conjugated to the polystyrene (PS) magnetic microparticle surface. The attachment of long-chained polymer chains which may switch the partition behavior, can be simply performed by S_N2 substitution of various polymers having primary amine functional groups, with p-toluenesulfonyl (tosyl)-activated polystyrene magnetic micro-particles. The surface modification of microparticle was probed by infrared microscopy. The distinctive peak represents N-H stretching vibration mode for microparticles after the reaction and it is common for all three polymers examined. The locations of main peaks are similar for all micro-particles but different and distinguishable in fingerprint region.

• Journal of Embryo Transfer
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• v.11 no.1
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• pp.41-50
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• 1996

This experiment was carried out to investigate the ovarian responses of the ovulation point, ovarian weight and size, the number of ovarian follicles and collected embryos, and to study the effects of the developmental stages (oocytes, 2-4 cell. 8-16 cell and morulae), additional levels of Ficoll (0, 15, 30%) on the survival rate (FDA-test) of rat embryos frozen in vitrification solution (20% glycerol + 10% ethylene glycol + 10% sucrose). Sunanarized results was as follows; 1. The mean ovulation point per head was 7, and the weight of ovaries was 0.03g. The size of ovary was 5.9 mm(L) and 4.6 mm(W), and the number of ovarian follicles over and below 2 mm was 4.7 and 8.7, respectively. The number of the collected embryos per head was 5.5 (79%). 2. 2. The FDA score of embryos frozen in 20 G 10 E 10 S without Ficoll was 2.8 (oocyte), 2.6 (2-4 cell), 3.9 (8-16 cell) and 3.6 (morula), respectively. However, there were no significant differences among treatments. 3. The FDA score of embryos frozen in 20 G 10 E 10 S with 15% Ficoll was 3.4 (oocyte), 4.0 (2-4 cell), 4.7 (8-16 cell) and 4.8 (morulae), respectively (P>0.05). 4. The FDA score of embryos frozen in 20 G 10 E 10 S with 30 % Ficoll was 3.7 (oocyte), 3.2 (2-4 cell), 4.4 (8-16 cell) and 4.4 (morulae), respectively (P>0.05). 5. As shown in the above results, the higher survival rate was obtained in the treatment of 15% Ficoll than that of 30%. And the survival rate (FDA-test)of the oocytes and 2-4 cell stages of the rat embryos was lower than that of 8~16 cell and morulae stages. It was considered that 8-16 cell and morulae could be available for the successful freezing by vitrification of rat embryos with 15% Ficoll except for oocytes.

• Journal of Embryo Transfer
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• v.27 no.4
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• pp.259-264
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• 2012

Solution of glycerol, ethylene glycol, sucrose, dextrose (GESD) and cryotop methods were carried out to investigate the survivability on vitrification of embryos. Embryos cultured in vitro were vitrified by GESD of 10 or 8 step and cryotop methods of 6 step, from cryopreservation step to frozen-thawed and culture step. Survival rate and ICM, TE cells of embryos were investigated after frozen-thawed 24 h. As a results, cryotop method was significantly (p<0.05) higher ($85.76{\pm}5.3$ vs. $66.71{\pm}2.4$, $44.80{\pm}2.1%$) than GESD 10 or 8 step methods on survivability. Also, In ICM cell number, cryotop method was significantly (p<0.05) higher to $45.67{\pm}4.7$ cells than GESD 8 step method. TE cell number was significantly (p<0.05) highest to $111.00{\pm}11.0$ cells in cryotop method. On the other hand, survival rate, TE and total cell number were all the significantly (p<0.05) high, except ICM in GESD 10 step method between GESD 10 step method and GESD 8 step method. In conclusion cryotop method was to be most effective, but it is considered necessary to study vitrification method for step-by-step freezing and thawing process.

• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.85-93
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• 1988

Solvolyses of t-butylhalides (X = Cl, Br, I) in quasi isodielectric solvent system, MeOH-nitromethane, MeOH-nitrobenzene and MeOH-ethyleneglycol have been studied kinetically. Methanolyses for t-butylhalides in MeOH-NM and MeOH-NB show rate maxima at 40~100 % (v/v) MeOH. The rate maxima observed have been interpreted as a result of cooperative enhancement of polarity-polarizability and hydrogen bonddonor ability of solvents. The influences of polarity-polarizability and hydrogen bonddonor ability on reactivities of substrates have been discussed in terms of Y value changes. The solvolysis rates for t-butylhalides in E.G. are more than 20 fold faster than those in MeOH and this was attributed to the solvent structure of E.G.

• Polymer(Korea)
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• v.35 no.5
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• pp.458-466
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• 2011

In the mixed system of supercritical carbon dioxide/organic solvents, poly(vinyl alcohol)(PVA) film of high degree of hydrolysis could be dyed with a dichroic dye of C. I. direct black 22(DB22) and as a result, high durability was obtained. Especially, as a dye dispersant in a supercritical fluid phase, a mixed solvent system of ethylene glycol: dimethyl sulfoxide=4 : 6 weight ratio was investigated. Then the optimum pressure for dyeing could be reduced down to 200 bar. Using this supercritical fluid system, the maximum dyeing appeared as the transmittance of less than 1% and the waste amount was reduced to the level of 1/10. After 500% drawing of this PVA film, both the polarizing efficiency of 94% and the single piece transmittance of 30% were obtained. The limitation of DB22 and further improvements were also discussed.

• Macromolecular Research
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• v.17 no.7
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• pp.458-463
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• 2009

Polyurethane (PU) is widely used as a cardiovascular biomaterial due to its good mechanical properties and hemocompatibility, but it is not adhesive to endothelial cells (ECs). Cell adhesive peptides, GRGDS and YIGSR, were found to promote adhesion and spreading of ECs and showed a synergistic effect when both of them were used. In this study, a surface modification was designed to fabricate an EC-active PU surface capable of promoting endothelialization using the peptides and poly(ethylene glycol) (PEG) spacer, The modified PU surfaces were characterized in vitro. The density of the grafted PEG on the PU surface was measured by acid-base back titration to the terminal-free isocyanate groups. The successful immobilization of pep tides was confirmed by amino acid analysis, following hydrolysis, and contact angle measurement. The uniform distribution of peptides on the surface was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). To evaluate the EC adhesive property, cell viability test using human umbilical vein EC (HUVEC) was investigated in vitro and enhanced endothelialization was characterized by the introduction of cell adhesive peptides, GRGDS and YIGSR, and PEG spacer. Therefore, GRGDS and YIGSR co-immobilized PU surfaces can be applied to an EC-specific vascular graft with long-term patency by endothelialization.

• Korean Journal of Plant Resources
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• v.19 no.3
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• pp.385-391
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• 2006

In vitro-grown axillary buds of Melia aredarach were successfully cryopreserved by vitrification. On the MS medium supplemented with BA 1 mg/L, multiple shoots were developed within $4{\sim}5$ weeks. Plantlets of Melia azedarach were cold-hardened at $10^{\circ}C$ for a 16-hr photo-period for 6 weeks. Excised axillary shoot-tips from hardened plantlets were precultured on a solidified Murashige & Skoog agar medium (MS) supplemented with 0.7 M sucrose for 1 day at $25^{\circ}C$. Axillary shoot-tip meristems wert dehydrated using a highly concentrated vitrification solution (PVS2) for 60 min at $0^{\circ}C$ prior to a direct plunge into liquid nitrogen (LN). The PVS2 vitrification solution consisted of 30% glycerol (w/v), 15% ethylene glycol (w/v), 15% DMSO (w/v) in MS medium containing 0.4M sucrose. After short-term warming in a water bath at $40^{\circ}C$, the meristems were transferred into 2 ml of MS medium containing 1.2M sucrose for 15 min and then planted on solidified MS culture medium. Successfully vitrified and warmed meristems resumed growth within 2 weeks and directly developed shoots without intermediary callus formation. The survival rate of cold-hardened plantlets for 3 and 4 weeks was 90%. We did not find any difference in PCR-band patterns between control and cryopreserved plants. This method appears to be a promising technique for cryopreserving axillary shoot-tips from in vitro-grown plantlets of Medicinal plants.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.3-8
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• 1986

The investigation of the effect of solvent structure on the first-order solvolysis of cis-$[Co(en)_2ClNO_2]^+$ion has been extended to water + co-solvent mixtures where the co-solvents are glycerol, ethylene glycol, isopropyl alcohol and t-butyl alcohol. Rates of solvolysis have been evaluated by spectrophotometric method at temperature 25∼30$^{\circ}$C. The polarity of solvent has influence on the variation of rate constant. The non-linear plot of the rate constant in log scale versus $\frac{D-1}{2D+1}$ implies that change in solvent structure with composition plays an important role in determining the variation of rate constant. The linearity of the plot of the rate constant in log scale versus the Grundwald-Winstein Y factor confirms that the solvolysis is an Id-type process with considerable extension of the metal chloride bond in the transition state. In the Kivinen equation the slope of the plot of log k versus $log(H_2O)$ suggests that the solvolysis is also an Id-type process. The application of free energy cycle shows that the effect of solvent structure is greater in the transition state than in the initial state.

• Korean Journal of Materials Research
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• v.24 no.2
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• pp.73-80
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• 2014

Ink-jet printing technology has been widely attractive due to its facility for direct and fine printing on various substrates. Recent studies have focused on expanding the application of ink-jet printing technology from general consumer use and design companies to the prototype production of precision parts and parts manufacturing. The use of ink-jet printing technology in decorated tableware, tiles, and other ceramic products also has many advantages. The printing process is fast and can be adaptable to various kinds of objects because there is no direct contact point between the printer and the substrates to be printed. For application to ceramic product decoration, inks containing highly dispersed inorganic nano-pigments are required. Here we report the synthesis and characterization of blue $CoAl_2O_4$ nanopigment for ink-jet printing. Blue ceramic ink based on the obtained $CoAl_2O_4$ pigment was prepared by dissolving $CoAl_2O_4$ pigment in a mixed solution of ethylene glycol and ethanol with volume ratios of 7:3 and 8:2, respectively, to obtain the appropriate viscosity for ink-jet printing. The ink solution contained 15 wt% of $CoAl_2O_4$ pigment and Cetyltrimethyl ammonium bromide(CTAB) and Sodium dodecyl sulfate(SDS) as dispersive agents. The prepared blue ceramic ink was stably jetted and formed a sphere-shaped droplet from an ink-jet printer.