• Journal of Navigation and Port Research
• /
• v.37 no.2
• /
• pp.129-135
• /
• 2013

Recently, waste water treatment system is developed in small and middle size to get more economic advantage. Freeze concentration system has high thermodynamic efficiency and low energy consumption, can re-use purified water and cold energy obtained from ice. This study was experimentally performed to investigate pollution containment in frozen layer by cooling wall temperature, air-bubble flow methods, initial ice-lining thickness of frozen layer in NaCl aqueous solution and the representative heavy metals, Pb and Cr aqueous solution. As the result, a decrease in the cooling wall temperature bring a higher growth rate of ice front and the more solute was involved in frozen layer. The method to inject directly air-bubble into ice-liquid interface through ring shape nozzle gave high purity of ice compared to indirect method. Ice lining in 5mm thickness resulted in frozen layer with higher purity than 1mm thickness.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2006.06a
• /
• pp.51-52
• /
• 2006

This study was progressed on the freezing behavior of waste water in relation to freeze concentration method useful to waste water treatment system of small and middle size and which can re-use purified water. The object of this experiment is comparing a pollutant contain of the frozen layer and of an aqueous solution by cooling wall temperature, a flow field effect and a initial thickness of frozen layer.

• Journal of the Korea Concrete Institute
• /
• v.17 no.3 s.87
• /
• pp.455-464
• /
• 2005

Today the application of antiwashout underwater concrete to the construction sites is increasing steadily, while its reliability is in issue. Particularly, antiwashout underwater concrete is known to have very weak durability on frost attack, and hence Japan society of civil engineers(JSCE) regulated that not to use of antiwashout underwater concrete where the freezing and thawing is suspected. This study aims the improvement of the freezing and thawing resistance for antiwashout underwater concrete. From the results of fundamental test, FA20 and SG50 showed good performance in fluidity and long term compressive strength than control concrete. Meanwhile, MK10 marked the highest compressive strength through the whole curing age but a defect on fluidity was discovered. The results from the repeated freezing and thawing test show that the large volumes of air entrapped by cellulose based antiwashout underwater admixture gave bad effects to frost durability and hence not much benefits were confirmed from the use of mineral admixtures. However there were some increasing effects on frost durability of MK10 and SG50 by securing $6{\pm}0.5\%$ of entraining air. In the meantime, there was a increasing tendency of frost durability by increasing blame's fineness of ground granulated blast furnace slag.

• Korean Journal of Animal Reproduction
• /
• v.24 no.3
• /
• pp.263-268
• /
• 2000

The development of single blastomeres isolated from 2-, 4- and 8-cell mouse embryos and the ability of such blastomeres to survive slow freezing were studied. Of 223, 60 and 188 single blastomeres isolated from 2-, 4- and 8-cell mouse embryos, respectively, 111 blastomeres (49.8%) from 2-cell embryos, 12 blastomeres (20.0%) from 4-cell embryos and blastomeres (16.5) from 8-cell embryos developed into blastocysts after culture for 96 hrs. The recovery rate was 54.2% (65/120), 46.4% (13/28) and 24.3% (17/70) of blastomeres derived from 2-, 4- and 8-cell embryos following freezing and thawing and the survival of frozen-thawed blastomeres was 27.1% (16/59), 36.4% (4/11) and 17.6% (3/17), and respectively. The apparently six normal fetuses were obtained from frozen-thawed blastomere from 2-cell embryos after transferring into the recipients. These results indicate that mouse btastomeres isolated from preimplatation stage embryos can survive storage in liquid nitrogen following slow freezing.

• Journal of Embryo Transfer
• /
• v.18 no.1
• /
• pp.1-14
• /
• 2003

This study was conducted to investigate that the immature and mature oocytes of porcine can be cryopreserved by vitrification. Oocytes were centrifuged to polarize the cytoplasmic lipid droplets. The lipids were removed from cytoplasm by micromanipulation. Delipated oocytes were centrifuged after being preincubated with cytochalasin B(CB) fer 10 min, and lipid droplets were removed. Centrifuged oocytes were treated with CB and centrifuged to polorize lipid droplets but not delipated and control oocytes is not-treatment. Oocytes of three types were vitrified in electron microscope(EM) grids. The results of survival, maturation and cleavage rates were as follows. 1 The survival rates of immature oocytes were 15.1%, 0% and 0% in the Delipated, Centrifuged and Control after vitrification, respectively, and its rate of Delipated wassignificantly higher than Centrifuged and Control(P<.01). 2. The survival rates of mature oocytes were 12.21%, 0% and 0% in the Delipated, Centrifuged and Control after vitrification, respectively, and its rate of Delipated was significantly higher than Centrifuged and Control(P<.01). 3 The maturation rates of immature oocytes were 37.5% and 68.9% for metaphase II in the Delipated after vitrification and Non-vitrification, respectively, and its rate of Non-vitrification was significantly higher than Delipated after vitrification(P<.01). 4. The cleavage rates of immature oocytes were 12.5%, 0%, 0% and 56.1% in the Delipated, Centrifuged, Control after vitrification and Non-vitrification, respectively. It's rate of Delipated was higher than Centrifuged and Control, but there were no significant difference, and its rate of Non-vitrification was significantly higher than Delipated, Centrifuged and Control(P<.05). 5 The cleavage rates of mature oocytes were 25.0%, 0%, 0% and 67.9% in the Delipated, Centrifuged, Control after vitrification and Non-vitrification, respectively. It's rate of Delipated was higher than Centrifuged and Control, but there were no significant difference, and its rate of Non-vitrification was significantly higher than Delipated, Centrifuged and Control(P<.05).

• Korean Journal of Animal Reproduction
• /
• v.17 no.4
• /
• pp.339-346
• /
• 1994

An understanding of the structure and function of mammalian spermatozoa requires the iso-lation of these components. In this study, frozen-thawed bovine spermatozoa were treated by physical treatments (vortexing, 26 gauge needle, strained 26 gauge needles and freezing-thawing) or chemical treatments (trypsin, dithiothreitol, sodium dodecylsulfate and $\beta$-mercaptoethanoJ) to yield free heads and tails. The most effective treatment was repeated pumping of sperm suspension through a strained 26 gauge needle conneted to a syringe. Spermatozoa by this treatment were mainly broken at the junction of the head and the tail, resulting in 90-100% yields. Also, sperm head surface did not modify during strained 26 gauge needle treatment when either spermatozoa or sperm heads were incubated in 250${\mu}\textrm{g}$/ml of FITC-UEA 1 for 1 h at room temperature to detect the modification of sperm surface components. Other physical treatments were less efficient for the breakdown of spermatozoa. The effects of chemical treatments on bovine spermatozoa are not noticeable. Dissected sperm heads and tails should be fractional leading to nearly pure components by sucrose gradient centrifugation at 1,000 rpm for 15 min. The result suggest that the established method may be useful for the biochemical study of spermatozoal components, and the understanding of oocyte activation mechanism either by spermatozoal components during fertilization or microinjection of isolated components.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.5
• /
• pp.441-445
• /
• 2001

For the developement of probiotics, three strains haying psychorophilic and salt tolerant characteristics were isolated from Kimchi. Among the isolated strains, MGl9, MG89 and MG208 were identified as Lactobacillus brevis, Enterococcus faecium and Lactobacillus plantarum, respectively. The relationship between cryoprotectant and the viability of freeze dried strains has been studied. The most effective cryoprotectant for MGl9 was found to be 10% skim milk contained 1% soluble starch haying the survival rate of 71.4%. In MG89, 10% skim milk contained 1% sucrose and 10% skim milk contained l% fructose in MG208 were showed effective cryoprotectant having the survival rate 68.9% and 64.7%. respectively These results suggest that these isolated strains can play an important role as probiotics in aquaculture.

• Development and Reproduction
• /
• v.15 no.4
• /
• pp.281-289
• /
• 2011

The objective of this study was to investigate the effective cryoprotectants for the cryopreservation of porcine mesenechymal stem cells (pMSCs). In order to understand the effectiveness of various cryoprotectants on pMSCs, we studied the most commonly used cryoprotectants; dimethyl sulfoxide (DMSO), ethylene glycol (EG), DMSO and EG. pMSCs were isolated from bone marrow matrix of piglet (2 month) and characterized by alkaline phopshatase (AP) activity, colony forming, and differentiation to adipocyte. In slow cooling cryopreservation, the pMSCs were exposed to cell medium containing Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% DMSO, 1.5M EG and 5% DMSO/0.75M EG, respectively, and freezed to $-1^{\circ}C$/min from $25^{\circ}C$ up to $-80^{\circ}C$ in a cryo-container. The proportion of viable cells and the growing rates in fresh pMSCs were significantly (P<0.05) higher than those of other groups, but did not differ between the cryopreserved groups. The expression of Sox-2 and Nanog gene was increased by extending culture time in cryopreserved groups. The expression of Bax gene in cryopreserved groups was similar with fresh pMSCs. Moreover, the gene expression of adipocyte-specific marker as well as chondrogenic/osteogenic factors in cryopreserved groups was similarly to fresh pMSCs. Taken together, our results suggested that all these cryoprotectants of 10% DMSO, 1.5M EG and 5% DMSO/0.75M EG could be used for cryopreservation of the pMSCs.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2006.05a
• /
• pp.137-138
• /
• 2006

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2006.05a
• /
• pp.139-140
• /
• 2006