• Journal of Embryo Transfer
• /
• v.16 no.1
• /
• pp.29-34
• /
• 2001

To investigate the effect of co-transfer of trophoblastic vesicle (TV) with frozen-thawed in vitro Produced (IVP) bovine embryo on pregnancy rate, IVP blastocysts were transferred to synchronized recipients. Elongated blastocysts were recovered at Day 13 to 15, and dissected more than 4 pieces to removed the embryonic disc. Throphoblastic fragments were cultured for 48 hours to make throphoblastic vesicles (TVs). TVs were cryopreserved in ethylene glycol or vitrification solution and frozen-thawed TVs were co-transferred to recipients with frozen-thawed IVP embryos. 1 The recovery rate of elongated blastocyst on Day 13 to 15 was 22.5% (18/80) and the size of recovered elongated blastocysts was 0.2∼5.0mm. 2. Eighteen elongated blastocysts were dissected into 88 pieces and 61.4% of those pieces were formed to TV (54/88) 3. The viability of frozen-thawed TV in ethylene glycol was higher than in vitrified solution (92.8% vs. 68.8%) 4. The pregnancy rate in co-transfer with frozen-thawed TV and IVP blastocyst was better than transfer only IVP blastocysts (50.0% vs. 23.1%).

• Journal of Electrochemical Science and Technology
• /
• v.12 no.4
• /
• pp.387-397
• /
• 2021

Deep eutectic solvents have been established as feasible metal electroplating solvent alternatives over traditional toxic aqueous plating baths. However, water, either added intentionally or unintentionally, can significantly influence the solvent's physical properties and performance, thereby hindering its industry application. In this study, the hygroscopicity, or the ability to absorb moisture from the environment, of synthesized ethaline (1:2 choline chloride:ethylene glycol) was investigated. The kinematic viscosity, electrical conductivity, electrochemical window, and water content of ethaline were monitored over a 2-week period. Karl Fischer titration tests showed that ethaline exposed to the atmosphere displayed significant hygroscopicity compared to its unexposed counterpart. ¹H NMR spectroscopy revealed that water vapor was readily absorbed at the surface due to the hydrophilic groups present in the ethaline molecule. Water uptake resulted in the decrease in viscosity, increase in electrical conductivity and narrowing of the electrochemical window of ethaline. Solution heating at 100℃ removed the absorbed moisture and allowed the recovery of the solvent's initial properties.

• Applied Chemistry for Engineering
• /
• v.28 no.4
• /
• pp.485-489
• /
• 2017

Polyethylene terephthalate (PET) has been widely applied in polymers and packaging industries to produce synthetic fibers, films, drink bottles or food containers. Therefore, it has become one of the major plastic wastes. In this article, glycolysis known as one of the main methods in PET chemical recycling was investigated using a glycol to break down the polymer into a monomer. Glycolysis of PET and ethylene glycol was performed in a micro-tubing reactor under various conditions. The effect of glycolysis conditions on the product distribution was investigated at experimental conditions of the EG/PET ratio of 1~4, the reaction time of 15~90 min and the reaction temperature of $250{\sim}325^{\circ}C$ with Mn and Cu catalysts. The highest yield of bis (2-hydroxyethyl) terephthalate monomer (BHET) was obtained as 89.46 wt% under the condition of the reaction temperature of $300^{\circ}C$ and the time of 30 min using 10 wt% $Cu/{\gamma}-Al_2O_3$ catalyst, with the PET and ethylene glycol ratio of 1 : 2.

• Clinical and Experimental Reproductive Medicine
• /
• v.17 no.2
• /
• pp.167-172
• /
• 1990

This study was carried out to clarify the effects of various kinds of cryoprotectants which were frequently used in freezing embryos of domestic animals on the survival of frozen-thawed mouse embryos. Mouse embryos were collected by hyperstimulation induction of ICR mouse. The samples were slowly cooled ($l^{\circ}C/min$) to temperatures between $-7^{\circ}C$ and $-30^{circ}C$ before direct transfer to liquid nitrogen ($-196^{\circ}C$) and thawed rapidly ($-500^{\circ}C$/min). As cryoprotectants, Glycerol, DMSO, Ethylene glycol and Propylene glycol were used and applied each 2 cell, 8 cell, morula in embryo stage. After normal mouse embryos developed to blastocyst by in vitro culture, we observed recovery rate and developing rate of embryos at thawing. The results obtained in these experiments were as follows : 1. The in vitro development rate from the frozen-thawed 2 cell embryos to the blastocyst were 67.7% in ethylene glycol, 65.7% in Propylene glycol, 55.2% in glycerol and 50.0% in DMSO respectively. 2. The in vitro development rate from the frozen-thawed 8 cell embryos to the blastocyst were 83.6% in DMSO, 75.7% in glycerol, 52.2% in propylene glycol respectively. 3. The in vitro development rate from the frozen-thawed morula to the blastocyst were 84.2% in glycerol, 80.0% in DMSO, 66.6% in propylene glycol and 55.2% in ethylene glycol respectively.

• Korean Chemical Engineering Research
• /
• v.46 no.2
• /
• pp.348-355
• /
• 2008

Recently, an understanding of new sources of liquid hydrocarbons such as bio-ethanol is economically very important. The present dissertation is also designed with purpose of developing the energy-saving process for the separation of bio-ethanol. In order to illustrate the predictability of proposed process for the separation of bio-ethanol, the experimental data from literatures and real plant data are used. Application of the thermodynamics of multicomponent mixtures and phase equilibria to the extractive distillation process with syntheses of heat exchanger network has enabled the development of energy-saving process for different separating agents. Developed process is capable of minimizing the energy usage and the environmental effect. This extractive process is also able to properly describe the effect of impurities, the choice of separating agent. Simulation results of extractive distillation using ethylene glycol show that impurities do not affect to extractive distillation operation and agent, ethylene glycol, was recycled without any loss. It is possible that extraction distillation has various heat network for anhydride ethanol and recovery of ethanol is maximized. Ethylene glycol as separating agent has a high boiling point to eliminate azeotropic point and on the contrary solubility of agent is low to be almost completed recovered. Proposed process is also the energy efficient process configuration in which 99.85mole% anhydride ethanol can be produced with low energy of 1.37198 (kg steam/kg anhydride ethanol).

• Journal of Embryo Transfer
• /
• v.23 no.1
• /
• pp.19-24
• /
• 2008

The purpose of this study was to compare the efficiency of slow freezing with that of vitrification method for the cryopreservation of human embryos. Human embryos were derived from in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and the mixed solution of propanedial (1.5, 1.0, 0.5M PROH) and sucrose (0.1M), ethylene glycol (7.5, 15%), dimethyl sulfoxide (7.5, 15% DMSO), sucrose (0.5, 1.0M) and SPS (Serum Protein Substitute) was used for a cryoprotectant for slow freezing and vitrification solution, respectively. Rates of recovery after thawing, morphological normality, post-thaw viability, arrest, morphological abnormality and preimplantation development were compared between two protocols. After freezing-thawing, recovery and survial rate of slow freezing was (88.6% and 73.4%), whereas vitrification was (99.2% and 96.2%) (p<0.05). The arrest rate of slow freezing was significantly lower compared with those of vitrification(8.7% vs 29.9%) (p<0.05). Preimplantation development to the 2-cell (83.8% vs 67.7%), 4-cell (69.0% vs 47.2%) and 8-cell (62.4% vs 37.8%) stages 24, 48 and 72 h after thawing, respectively, were higher in the slow freezing than the vitrification. After slow freezing and vitrification of human embryo at 2-8cell stage, the rate of recovery rate, survival rate and partial damage rate were 92.0% vs 100%, 80.4% vs 96.2% and 52.2% vs 19.0%, respectively. And partial damage rate was significantly lower than those of slow freezing method (p<0.05). These results demonstrate that a slow freezing using PROH is more efficient than a vitrification for cryopreserving the human zygotes, although the vitrification yielded better recovery, survival and partial damage of frozen-thawed 2-8 cell stage embryos than slow freezing method.

• Resources Recycling
• /
• v.3 no.1
• /
• pp.17-24
• /
• 1994

Recovery of precious metal values from petrochemical spent catalyst is important from the viewpoint of environmental protection and resource recycling. Two types of spent catalysts were used in this study. One used in the manufacture of ethylene contains 0.3% Pd in the alumina substrate. The other used in oil refining contains 0.3% Pt and 0.3% Re. Both spent catalysts are roasted to remove volatile matters as carbon and sulfur. Then, metallic Pd powder from Pd spent catalyst is obtained in the course of grinding, hydrochloric acid or aqua regia leaching and cementation with iron. For the recovery of Pt and Re from Pt-Re spent catalyst, Pt and Re are leached with either HCI or aqua regia, first. Metallic Pt powder is recovered from the leach solution by cementation with Fe powder. Re in sulfide form is precipitated by the addition of sodium sulfide to the solution obtained after Pt recovery. It is found that 6N HCI can be successfully used as leaching agent for both types of spent catalyst. 6N HCI is considered to be better than aqua regia in consideration of reagent and equipment cost.

• Journal of Food Hygiene and Safety
• /
• v.28 no.1
• /
• pp.56-62
• /
• 2013

Poly (ethylene naphthalate) (PEN), which is likely to be widely used in various application due to good barrier properties, is manufactured by condensation polymerization of 2,6-dimethylnaphthalene dicarboxylate (2,6-NDC) or 2,6-naphthalene dicarboxylic acid (2,6-NDA) with ethylene glycol. In this study, an analytical method to determine monomers in food simulants, which might migrate from PEN food contact materials into food, was developed. The HPLC-UV method was validated for 2,6-NDC and 2,6-NDA. The obtained validation parameters were selectivity, sensitivity, linearity, precision and recovery. The simultaneous HPLC method was considered the be most effective analytical method to determine 2,6-NDC and 2,6-NDA in food simulants.

• Resources Recycling
• /
• v.20 no.6
• /
• pp.50-55
• /
• 2011

Using ultrasonic irradiation, the separation and recovery of PV cell, made of silicon wafer, from PV module was carried out through selective decomposition of EVA used as an interlaminated binder. The ultrasonic cleaner of bath-type (Output: 130 W, Frequency: 40 kHz) was used as an ultrasonic apparatus in this research. With the fixed distance of 2 cm, from ultrasonic generator to PV cell, the experiment of EVA decomposition was performed in various organic solvents such as Toluene, Trichloroethylene, O-dichlorobenzene, Benzene. And also their concentrations and temperature was changed to survey the optimum conditions. However EVA can be decomposed perfectly at $55^{\circ}C$ within 160 min in 5 M of all kinds of solvent, PV cell may be recovered with being damaged or broken severely. This damage may be resulted from the swelling of EVA in the process of decomposition. Whereas, at the condition of 5 M at $65^{\circ}C$, PV cell can be recovered with the state of minor damage or crack. This implies that the decomposition rate of EVA increases with an increase of temperature, thereby EVA can be decomposed before the swelling of EVA layer. Conclusively, it is possible for PV cell to be recovered within 40 min, at $65^{\circ}C$ in 5 M, with less damage.

• Fibers and Polymers
• /
• v.2 no.3
• /
• pp.122-128
• /
• 2001

UV-curable polyurethane acrylate prepolymers were prepared from diisocyanates [isophorone diisocyanate (IPDI), 2,4-toluene diisocyanate (TDI), or 4,4'-dicyclohexylmethane diisocyanate (H$_{12}$MDI)], diols [ethylene glycol (EG), 1,4-butane diol (BD), or 1,6-hexane diol (HD)], polypropylene glycol as a polyol. UY-curable mixtures were formulated from the prepolymer (90 wt%), reactive diluent monomer trimethylol propane triacrylate (10 wt%). and photoinitiator 1-hydroxycy-clohexyl ketone (3 wt% based on prepolymer/diluent). The effects of different diisocyanates/low molecular weigh dial on the dynamic mechanical thermal properties and elastic recovery of UV-cured polyurethane acrylate films were examined. The tensile storage modulus increased a little in the order of EG > BD > HD at the same diisocyanate. Two loss modulus peaks for all samples are observed owing to the glads transition of softs segments ($T_gh$) and the glass transition temperature of hard segments ($T_gh$). For the same diisocyanate, $T_gh$, decreased, however, $T_gh$ increased, in the order of HD > BD > EG. The elastic recovery also increased in the order of HD > BD > EG at the same diisocyanate. In case of same diols, $T_gh$ increased in the order of $H_12$MDl > TDI > IPDI significantly. The ultimate elongation and elastic recovery increased in the order of TDI > IPDI > $H_12$MDl at the same diol.l.