• Clinical and Experimental Reproductive Medicine
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• v.38 no.1
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• pp.24-30
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• 2011

Objective: The objectives of this study were to analyze efficacy of immature and mature mouse oocytes after vitrification and warming by applying various combinations of cryoprotectants (CPAs) and/or super-rapid cooling using slush nitrogen ($SN_2$). Methods: Four-week old ICR female mice were superovulated for GV- and MII-stage oocytes. Experimental groups were divided into two groups. Ethylene glycol (EG) only group: pre-equilibrated with 1.5 M EG for 2.5 minutes and then equilibrated with 5.5 M EG and 1.0 M sucrose for 20 seconds. EG+dimethylsulfoxide (DMSO) group: pre-equilibrated with 1.3 M EG+1.1 M DMSO for 2.5 minutes and equilibrated with 2.7 M EG+2.1 M DMSO+0.5 M sucrose for 20 seconds. The oocytes were loaded onto grids and plunged into $SN_2$or liquid nitrogen ($LN_2$). Stored oocytes were warmed by a five-step method, and then their survival, maturation, cleavage, and developmental rates were observed. Results: The EG only and EG+DMSO groups showed no significant difference in survival of immature oocytes vitrified after warming. However, maturation and cleavage rates after conventional insemination were greater in the EG only group than in the EG+DMSO group. In mature oocytes, survival, cleavage, and blastocyst formation rates after warming showed no significant difference when EG only or EG+DMSO was applied. Furthermore, cleavage and blastocyst formation rates of MII oocytes vitrified using $SN_2$ were increased in both the EG only and EG+DMSO groups. Conclusion: A combination of CPAs in oocyte cryopreservation could be formulated according to the oocyte stage. In addition, $SN_2$ may improve the efficiency of vitrification by reducing cryoinjury.

• Macromolecular Research
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• v.13 no.5
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• pp.373-384
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• 2005

Novel pH-sensitive moieties containing an s-triazine ring were synthesized with sulfonamide and secondary amino groups. The synthesized pH-sensitive moieties were used for the synthesis of a pH-sensitive amphiphilic ABA triblock copolymer. The pH-sensitive triblock copolymer was composed of diblock copolymers, methoxy poly(ethylene glycol)-poly ($\varepsilon$-caprolactone-co-D,L-lactide) (MPEG-PCLA), and pH-sensitive moiety. These copolymers could be dissolved molecularly in both acidic and basic aqueous media at room temperature due to secondary amino and sulfonamide groups. The synthesized s-triazine rings containing pH-sensitive compounds were characterized by ${^1}H-NMR,\;{^13}C-NMR$, and LC/MSD spectral data. The synthesized diblock and triblock copolymers were also characterized by ${^1}H-NMR$ and GPC analyses. The critical micelle concentrations at various pH conditions were determined by fluorescence technique using pyrene as a probe. Furthermore, the micellization and demicellization study of the triblock copolymer was done with pH-sensitive groups. The sensitivity towards pH change was further established by acid-base titration.

• Textile Coloration and Finishing
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• v.34 no.1
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• pp.10-19
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• 2022

Humectants are chemical compounds which added to water based pigment inks for DTP (Digital Textile Printing) to prevent evaporation of water. The humectants usually have diol or triol type chemical structures and their -OH groups have possibility to react with functional groups of the binder polymers, such as ester, carboxylic acid, and urethane groups, acting as a crosslinking agent. The crosslinking reactions between polymer binders and humectants in inks can affect touch of the printed fabrics. In this regard, this study aims to investigate effect of chemical structures and added amounts of humectants in pigment ink on touch of dyed fabrics by using 1,6-hexanediol, ethylene glycol, diethylene glycol, and 1,4-buthanediol with various amounts added to the mixture of a black pigment and a polyurethane type binder. Then, color, rubbing strength, touch of the fabrics dyed with the prepared pigment inks were evaluated.

• Journal of Food Hygiene and Safety
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• v.5 no.1
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• pp.13-19
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• 1990

The microbial populations of exportable ginseng leaf tea were $3.6{\times}10^{5}/g$ in mesophilic aerobic bacteria, $2.1{\times}10^{3}/g$ in mesophilic aerobic spores, $1.6{\times}10^{4}/g$ in yeast, $1.9{\times}10^{4}/g$ in molds and $1.2{\times}10^{4}/g$ in coliforms, respectively, which are higher levels than the legaJIy permissible loads of microorganisms for ginseng powders in Korea. In a comparative study of the decontaminating effects on microorganisms, ethylene oxide fumigation and 5 kGy irradiation could decrease microorganisms below the detectable level. And there is no growth of microorgllnisms after three months of storage at $30{\pm}1^{circ}C$. The decimal reduction doses (Dw value) for microorganisms contaminated were 0.70 kGy in coliforms, 0.75 kGy in total bacteria, 0.85 kGy in molds. and 0.95 kGy in yeast, respectively. In the organoleptic test for ginseng leaf tea, the irradiated samples showed no significant difference from the control group in overall flavor, taste, color and acceptability. However the extracts of ethylene oxide fumigated sample were significantly different in color and taste from other groups even after three months storage.

• Polymer(Korea)
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• v.36 no.1
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• pp.111-116
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• 2012

A functionalization of mesoporous materials with organosilane was carried out via a post-synthesis grafting method and $(n-BuCp)_2ZrCl_2$/methylaluminoxane (MAO) as subsequently immobilized on the functionalized mesoporous materials for ethylene polymerization. Organosilanes having amine, cyano or imidazoline group such as $N$-[(3-trimethoxysilyl)propyl]ethylenediamine (2NS), 4-(triethoxysilyl)butyronitrile (1NCy), 1-(3-triethoxysilylpropyl)-2-imidazoline (2NIm) were used for the surface functionalization of mesoporous materials. In the SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ catalyst preparation, the amount of MAO in feed increased with an decrease in the Zr content of the supported catalyst, and Al content in the supported catalyst increased. The ethylene homopolymerization activity of SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ dramatically increased as the amount of MAO in feed increased. Furthermore, when the immobilization time was 6 hrs, SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ showed the highest activity. The activities of supported 2NS-, 1NCy-, 2NIm-functionalized catalysts decreased in the following order, SBA-15/2NS/ > SBA-15/2NIm/ > SBA-15/1NCy/$(n-BuCp)_2ZrCl_2$. 2NS and 2NIm which have two amine groups per silane molecule were shown to interact with $(n-BuCp)_2ZrCl_2$ strongly compared to 1NCy which has one amine group. Thus, the activities increased with an increase in the nitrogen and the Zr content of the supported catalysts.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.2
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• pp.121-129
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• 2001

Objective: The aim of this study is to compare the efficiency of a method for the cryopreservation of mouse blastocyst.. Methods: Mouse embryos were obtained at 2-cell stage and cultured to blastocyst stage in T6 medium supplemented with 10% fetal bovine serum. Morphologically normal blastocysts were collected and randomly divided to one control and four experimental groups. In control group, blastocysts were cultured in vitro continuously for additional two days. In group 2, blastocysts were exposed to vitrification solution (ethylene glycol) only without cryopreservation (exposure only group). In group 3, 4 and 5, blastocysts were cryopreserved by slow-freezing procedure with glycerol (slow-fteezing group) or by vitrification procedure using EM grids (EM grids group) and cryoloop (cryoloop group), respectively. Frozen blastocysts were thawed and cultured for additional two days. Twenty four hours after thawing, some blastocysts were fixed and stained with Hoechst 33342 (bisbenzimide) and the number of nuclei in each blastocysts were counted to confirm the survival of bias to cysts in experimental groups. Results: Survival rate and hatching rate of the blastocysts in slow-freezing group (24 h: 72.4% and 66.0%, 48 h: 63.2% and 64.6%) and EM grids group (24 h: survival rate 77.3%, 48 h: 70.1% and 71.4%) were significantly lower ($X^2$-test p<0.05) than those of control group (24 h: 93.4% and 86.0%, 48 h: 88.5% and 90.7%). In contrast, the survival rate and hatching rate of the blastocysts in cryoloop group (24 h: 84.1% and 84.1%,48 h 79.3% and 87.7%) is well compared with those in the control group. The mean (${\pm}SD$) cell number of blastocyst in the exposure only ($89.2{\pm}11.5$), EM grids ($85.0{\pm}10.3$) and cryoloop ($89.0{\pm}11.0$) groups, except slow-freezing group ($79.0{\pm}10.0$), were not significantly different from that of control group ($93.1{\pm}13.9$) 24 h after thawing (Student's t-test). Conclusion: This study demonstrates that higher survival rate of vitrified-thawed mouse blastocyst can be obtained using cryoloop as the embryo container at freezing rather than slow-freezing or vitrification using EM grids. The results of this study suggest that vitrification using cryoloop (with ethylene glycol) may be a preferable procedure for mouse blastocyst cryopreservation and could be applied to the human blastocyst cryopreservation.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.556-564
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• 2018

In this study, polyethylene oxide (PEO)/polyethylene-co-vinyl acetate (EVA)/multi-walled carbon nanotube (MWCNT)-COOH composite membranes were prepared by adding 1, 2, 3, and 5 wt% of MWCNT-COOH to PEO/EVA respectively. The gas permeation properties of $N_2$, $O_2$ and $CO_2$ at $30^{\circ}C$ and 4~8 bar pressure were investigated. In each PEO/EVA/MWCNT-COOH composite membranes, the permeability of $CO_2$ increased with increasing the pressure, but the permeability of $N_2$ and $O_2$ were independent of the feeding pressure. As the MWCNT-COOH content increased, the $CO_2$ permeability increased and then decreased above 2 wt% MWCNT-COOH content. The 2 wt% MWCNT-COOH composite membrane exhibited a $CO_2/N_2$ selectivity of 77.8 and a $CO_2$ permeability of 84 barrer at 8 bar. The high $CO_2/N_2$ selectivity and $CO_2$ permeability were due to the high affinity between the quadrupolar $CO_2$, polar ether groups of PEO, and the polar ester groups of EVA. Additionally, the strong affinity between $CO_2$ and the -COOH groups on the MWCNT surface contributed to the high permeability of $CO_2$.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.2
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• pp.117-124
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• 2007

Objective: The aim of this study was to compare the efficacy of slow freezing with vitrification method for cryopreservation of mouse pronuclear stage embryos. Methods: Mouse pronuclear embryos obtained from superovulated mice and classified into 2 groups of slow freezing and vitrification. Slow freezing solution consisted of 1.5 M PROH, 0.1 M sucrose, while vitrification solution consisted of 40% ethylene glycol, 18% Ficoll and 0.5 M sucrose diluted in Dulbecco's phosphate-buffered saline supplemented with 10% SSS. Recovery and survival rates after thawing and development rates to hatching balstocyst stage were compared between two groups. Results: After freezing and thawing, recovery rate of slow freezing group was 93.8%, whereas vitrification group was 66.5% (p<0.01). Survival rate of recovered embryos were similar between two groups as 83.2% in slow freezing and 87.6% in vitrification. Embryo development rates to 2-cell stage after 24 hrs (77.0% vs 59.1%), 4-cell after 48 hrs (72.6% vs 53.3%), blastocyst after 96 hrs (53.1% vs 40.1%) of thawing were significantly higher in vitrification group than those of slow freezing group, respectively. Conclusion: The vitrification method may provide better developmental competence of frozen-thawed embryos than that of slow freezing method for cryopreservation of mouse pronuclear stage embryos.

• Polymer(Korea)
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• v.28 no.4
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• pp.314-320
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• 2004

Soluble aromatic polyimides bearing 4-(4-oxyalkyleneoxystyryl)- pyridines (ethylene and hexylene) as photoreactive side groups were synthesized and characterized. The photoreactive polymers were soluble in various polar organic solvents and their films were easily formed by solution casting. The photoreactivities of the polymers in the film state were approximately 64% at an exposure energy of 1.5 J/$\textrm{cm}^2$. Transmittances of the polymer films were about 85% after annealing at 20$0^{\circ}C$. Therefore, these polymers can be evaluated to be photoreactive polyimides with good transparency and solubility. The dichroic ratios of the polymers with ethylene and hexylene groups as the alkylene spacers were 0.023 and 0.026, respectively. The order parameters of 4'-pentyl-4-bipheny1carbonitrile as a liquid crystal (LC) in the film cells of the former and latter polymers were 0.50 and 0.52, respectively. These results indicate that the polymers show the effect of alkylene spacer on the photoalignments. The LC in the film cells of the polymers was perpendicularly oriented to the electric vector of the linear polarized UV light (LPUVL).

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.797-804
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• 2006

The present study was undertaken to investigate the post-thawed survivability of bovine embryo depending on different dose of ethylene glycol and sucrose. Ovaries were collected at local slaughterhouse and the cumulus-oocyte-complexes aspirated from ovaries were in vitro matured, fertilized and cultured at 39°C in an atmosphere of 5% CO2 incubator. For conventional slow-freezing, d 7 or 8 expanded blastocysts were collected. Embryos were equilibrated in 1.5 M and 1.8 M ethylene glycol(EG) with 0.1 M and 0.3 M sucrose in Dulbecco's phosphate-buffered saline(D-PBS) supplemented with 0.5% bovine serum albumin. Embryos were then loaded individually into 0.25ml-straw and placed directly into cooling chamber of programmable freezer precooled to 󰠏7°C, after 2 min, the straw was seeded, maintained at 󰠏7°C for 8 min, and then cooled to 󰠏35°C at 0.3°C/min, plunged and stored in liquid nitrogen for at least 3 days. For thawing, the straw containing embryos were warmed in air for 10 sec and exposed to 37°C water for 20 sec. Straws were then removed from 37°C water. Rates of blastocyst survive and hatching were evaluated at 24 to 72 h post-warming. No difference of the survivability was shown between 1.5 M and 1.8 M EG (71 and 70%, respectively). Addition of 0.1 M sucrose to 1.5 M and 1.8 M ethylene glycol in the freezing solution did not differ significantly embryo survival (74 and 77%, respectively), whereas survival rates was higher(89%) in freezing solution contained 0.3M sucrose to 1.8M EG compared with 0.3M sucrose to 1.5M EG group(71%). However, there was no difference in the overall total cell number between the two groups (122±1.8 vs 131±1.4, respectively). In conclusion, the results suggest that 0.3 M sucrose in 1.8 M EG may be optimal condition for freezing and thawing methods with in vitro produced embryos and may be applied to on-farm conditions for embryo transfer.