• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.267-271
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• 2015

This study aimed to determine the optimal freezing temperature for preserving mulberries. Mulberries were frozen at -20, -45, and $-70^{\circ}C$ immediately after harvesting. After 24 h, frozen mulberries were stored at $-20^{\circ}C$ for two months and then thawed at $4^{\circ}C$ and room temperature. Frozen and thawed mulberries did not differ significantly in color and pH from fresh mulberries. However, the content of anthocyanidin and sugar, and the hardness of mulberry significantly decreased after feeze-thawing. Drip loss of the thawed berries increased as the freezing temperature decreased. A comparison among cross-section images of mulberries frozen at different temperatures did not show any significant differences. However, after thawing at $4^{\circ}C$ or room temperature, the total number of aerobic bacteria found in mulberry decreased more than ten times. Consequently, the freezing temperature showed no significant effect on the overall quality of the mulberry.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.520-527
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• 2020

Hwangtoh is the rich resource that accounts for about 15.0% of the domestic soil, and can be used as the admixture of concrete with Pozzolan characteristics if activated by rapidly freezing after burning with high temperature. In this study, the mortar curbs containing active hwangtoh were produced, based on the mixture for the mortar curbs sold on the market. The substitution rate of active hwangtoh were considered 10.0% and 25.0%, and the test items were selected to compressive and flexural strength tests, freezing/thawing resistance tests, accelerated carbonation tests, and accelerated chloride diffusion tests. In the results of the mechanical performance, it was showed that the highest strength was evaluated in OPC mixture, and the increase in strength was small by the increase of age, which was believed to be due to the fact that most of the strength in each mixture was created in three days of steam curing. The results of the freezing/thawing tests for 28 aged days showed the reduction rate of compressive strength was 85.0% or higher for all specimen, meeting the criteria presented. The accelerated carbonation tests were carried out on the specimen at 28 days of age, and the results showed that the mortar with active hwangtoh had lower carbonation resistance performance than mortar with OPC. The passed charge of each mixture was assessed in accordance with ASTM C 1202 on 28 and 91 aged days. The OPC mixture had "Low" rate and the mortar with active hwangtoh had "Moderate" rate. So it was thought that the mortar with active hwangtoh had appropriate resistance performance for chloride attack.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.95-102
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• 1997

The studies on the carried out to investigate the effective concentration of cryoprotectant agents and sucrose by one-step straw method of bovine embryos. The follicular oocytes were cultured in TCM-199 medium containing 10 IU/ml PMSG(Sigma, USA), 10 IU/ml hCG(Sigma, USA), 1$\mu\textrm{g}$/ml $\beta$-estradiol(Sigma, USA) and 10% FCS for 24~48 hrs in incubator with 5% CO2 in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 12~18 hrs with motile capacitated sperm by preincubation of heparin. The bovine embryos following dehydration by cryoprotective agents and various concentrations of sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water. Survival and in vitro developmental rate was defined as devellpmental rate on in vitro culture or FDA-test. The results are smmarized as followes : 1. The high in vitro developmental rates of bovine frozen embryos after rapidly thawed in freezing medium was attained 2.0M glycerol, 2.0M DMSO, 1M or 2.0M propanediol. 2. The high in vitro developmental rates of bovine frozen embryos after rapidly thawed in freezing medium was obtained single cryoprotectant(6.7~17.4%) than mixed cryoprotectants(6.7~16.7%). 3. In vitro developmental rate of bovine embryos after rapid frozen-thawing in the freezing medium added 0.25M and 0.50M sucrose were higher cleavage rate than those of sucrose concentration of 0.75M and 1.00M. 4. The freezing methods on in vitro developemental rates of bovine embryos was attained slow freezing method(9.70~15.6%) higher than rapid freezing method(9.4~13.3%).

• Journal of Embryo Transfer
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• v.6 no.1
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• pp.13-24
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• 1991

The objective of this experiment was to study some possibilities to simplify freezing, thawing and transfer procedure of one-step straw method comparing with the conventional methods using bovine embryos. The previous work are also designed to investigate the thawing effect by development stage and its quality using the embryos. Results obtained were summarized as follows: 1. A total of 87 embryos from 14 donor cows were frozen-thawed and an average of frozen embryo/donor was 6.2. 2. The survival rates of morula stage(65.4%) were higher than those of blastocyst stage(57.l%) and vice versa in rate of morphological recovery (80% vs 95.4%). However. no significant difference was denoted between them. 3. In difference between the groups of good quality and poor quality. good quality was resulted in a significantly higher embryo survival rate(75%) and recovery rates(95%) than poor quality(P<0.0l). 4. In effects of non-permeable sugar dilution in added to l.0M glycerol. higher survival rates were orderd in sucrose. lactose, raffinose and xylose. But lactose-raffinose, sucrose-trehalose and xylose in added to 2.OM glycerol. 5. The highest survival rates were obtained by direct plunge into the liquid nitrogen with 3.OM concentration both of glycerol and trehalose. 6. The survival rates in vitro condition of one-step and direct plunge methods(75%-87.5%) were significantly higher than those of multiple steps (21.4-52.6%) in in vitro (P<0.0l). However, the results of single-step were critical in comparing to other steps of final pregnant conformation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.3
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• pp.39-46
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• 1990

This paper was analized the thermal conductivity of polystylene (TENSAR- GEOGRID) embeding into the subbase through frost penetration depth, frost heave, change of bearing capacity, and soil moisture movement due to freezing, thawing and icing actions, and their results were as follows : 1.The change of temperature into the sub-base was much increased by the Tensar-Geogrid insertion, and the frost penetration and frost heave were decreased as the thinner of the insulation thickness but the thawing velocity of melting period was appeared to be faster in case of non-insulated. 2.The frost heave had a close relationship with the thickness of insulations which was reasonably included anti-frost effects. 3.The moisture content during the freezing period of upper layer of the insulation insertion was increased by 15 per cent but it was returned to initial state of the thawing period, and at the down layer temporarily increased by 10 per cent and returned to the original state at once. 4.The insulation was acted as a function of distribution of surcharge, and the settlement of the sub-base was about 1.5 mm under 15 tonnage of load and which was included within the allowable limits. 5.The sliding resistance due to the icing which was induced by the insulation insertion into the sub-base was appeared as more 40 per cent than noninsulation area, so that the insulations should be restricted on the place such as mountains, curved and cross area which were required the braking power under the traffics.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.791-796
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• 2014

Cryopreservation of epididymal sperm is an effective technique to preserve genetic materials of domestic cats and wild felids when they unexpectedly die. However, this technique inevitably causes detrimental changes of cryopreserved-thawed spermatozoa, for example, by physical damage and excessive oxidative stress. L-carnitine is an antioxidant that has been used to improve sperm motility in humans and domestic animals. This study aimed to investigate the effects of L-carnitine on cat epididymal sperm quality following cryopreservation and thawing. After routine castration, cauda epididymides were collected from 60 cat testes. The epididymal spermatozoa from 3 cauda epididymides were pooled as 1 replicate. Spermatozoa samples (16 replicates) were examined for spermatozoa quality and then randomly divided into 4 groups: 0 mM L-carnitine (control), 12.5 mM, 25 mM and 50 mM L-carnitine. The sperm aliquots were then equilibrated and conventionally frozen. After thawing, sperm motility, plasma membrane integrity, DNA integrity and acrosome integrity were evaluated. The 25 mM L-carnitine significantly improved sperm motility compared with a control group (p<0.05), although this was not significantly different among other concentrations. In conclusion, supplementation of 25 mM L-carnitine in freezing extender improves cauda epididymal spermatozoa motility. The effects of L-carnitine on the levels of oxidative stress during freezing and thawing remains to be examined.

• Journal of Embryo Transfer
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• v.27 no.1
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• pp.45-50
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• 2012

The objective of this study is to estimate the effect of adding TES to LEY and FGE freezing extender for the sperm viability, acrosomal morphology and DNA fragmentation from miniature pig sperm, we evaluated sperm characteristics in TFGE, TLE and LEY with various thawing condition ($37^{\circ}C$ for 20 sec, 45 sec and $75^{\circ}C$ for 5 sec, respectively), and in different concentration of glycerol at 1%, 1.5%, 3%. The sperm viability and normal acrosome intact(NAI) in TFGE (Viability : $60.3{\pm}2.4$, NAI : $58.6{\pm}2.2%$), TLE ($61.3{\pm}2.4$, $62.2{\pm}2.2%$) extender significantly(p<0.05) increased than that in LEY ($50.2{\pm}2.4$, $54.5{\pm}2.2%$) extender thawed at $75^{\circ}C$ for 5 sec. According to the results from glycerol concentration, the viability and NAI of miniature pig sperm in 1.5% glycerol TLE ($66.1{\pm}3.2$, $66.2{\pm}1.0%$) was highest among the experimental groups. In accordance with this, DNA fragmentation rates was the lowest in TLE ($43.3{\pm}0.5%$) while that in LEY ($63.5{\pm}2.3%$) is the highest. Therefore, these results suggest that TLE extender method for freezing- thawing of miniature pig sperm increased the viability after thawing.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.73-79
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• 2011

Based on the results of Part 1 of our two-parts paper, the possibility on field applicability of CMDS(Coal Mine Drainage Sludge) mixed with bentonite and cement as a liner in landfill sites was investigated. The optimum moisture content that met the landfill liner condition was obtained when the ratio of CMDS: bentonite: cement was 1: 0.5: 0.3 in a lab-scale. The relative compaction was measured in 90.1%, which results for construction field have been generally acceptable. In this study, a large-scale Lysimeter($1.0m{\times}1.5m{\times}2.0m$) was used to simulate the effects of the layer on the freeze/thaw by -20 average temperature. The mixture after freezing/thawing showed compressive strength more than $5kg/cm^2$, which was satisfied with EPA standards. Initial permeability of CMDS was $7.10{\times}10^{-7}cm/s$ and permeability its mixture after freezing/thawing was increased to $9.80{\times}10^{-7}cm/s$. The change of temperature in the layers rises and falls with linear and temperature gradient keep maintain the present state. Moisture contents in the layers have not been radically changed. Through the leaching test determined by KSLT method, it was found that heavy metals excluding Zn and Ni were not leached out or leached out less than the standards during 7 cycles of freezing/thawing process. Since it shows the increased permeability about 1.5 times and slight change in moisture content, but it was satisfied with EPA standar through 7 cycles of freezing/thawing process, this mixture can be applied as a liner in landfill final cover system.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.311-323
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• 1994

This study was conducted to observe seasonal and individual changes in semen characteristics and sperm freezability, and sperm penetration into zona-free hamster eggs in Korean native goats. Buck response and change in semen characteristics to electrical stimulations was evaluated for four seasons throughout 2 years and percentage of motile sperm and normal apical ridge acrosome was investigated after equilibration and thawing for 4 seasons with 5 bucks. Sperm penetration rate was evaluated for 4 bucks. 1. Probe insertion at depth of 7cm and repeated stimulation for 3 sec was more effective(P<0.05) in buck response and semen collection than those of other conditions. 2. Semen characteristics from electrojaculation was signficantly(P<0.005) higher in spring and fall for semen volume, in spring and summer for sperm concentration and in fall for sperm motility than those in other seasons, respectively. However, there were no differences in total sperm among seasons. 3. Buck response to electrical stimulation showed significant difference(P<0.05) among individuals in all 3 seasons except winter. Significant individual difference in semen volume was only in spring and summer, but there was no indivudual difference in sperm concentration and total sperm in all season. 4. Washing of semen before freezing treatment was greatly(P<0.05) beneficial to sperm motility after thawing, no matter whether ejaculates exhibit egg yolk coagulation or not. 5. Sperm motility after glycerol equilibration was significantly(P<0.05) low in summer semen and motility after thawing was greatly(P<0.05) higher in winter semen than in other seasons. Freezability of unwashed sperm was significantly difference among bucks, but a yearly freezability of washed sperm after chilling and thawing were no differences among bucks and percentage of normal apical ridge acrosome were not different among seasons and bucks. 6. There was no significant difference in sperm motility after thawing between egg yolk levels in summer, although 20% level gave more higher motility than 5% level. 7. In summer, 3.2% glycerol and 3-h equilibration gave greatest percentage(P<0.05) of sperm motility and normal apical ridge acrosome after thawing. 8. Sperm penetration rate into zona-free hamster eggs was not different between bucks and seasons. Overall, it is concluded that to obtain maximum sperm output and successive semen freezing by electrojaculation method, buck selection with good response in all season could be basically considered and that seasonal effect on sperm freezability was more greater than that of individual bucks.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.29-33
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• 2021

Purpose Plasma renin activity (PRA) test is important for the diagnosis of primary aldosteronism. PRA is an easily deformed substance in vitro and affected by temperature changes. Laboratory of ASAN medical center has consistently found that there was a difference between the initial and re-experimental results. We compared and analyzed the differences in PRA test results according to the sample storage status. Materials and Methods The measurement of PRA was performed by using the radioimmunoassay. From August to September 2020, 43 PRA re-test samples were tested with different sample storage condition. The first group was re-examined by freezing the plasma-separated samples at -18℃, and the second group was re-examined with refrigerated EDTA sample. Also, additional tests were conducted on 13 PRA samples to verify the effect on thawing temperature differences in plasma-separated samples. The same samples were divided into two parts and stored frozen at -18℃, respectively, and thawing samples in room temperature and those in refrigerator were were conducted. Each result was compared and analyzed based on the initial experimental results. Results The results of re-examination after frozen storing plasma separation samples showed a lower correlation than the results of re-examination with EDTA plasma samples in refrigerator. When calculating the percentage based on the initial test results, the average percentage of each was 404.9% and 133.8%. The correlation coefficient was also R=0.8501 and R=0.9966, respectively, showing a higher correlation between plasma in the refrigerated sample EDTA tube. In comparison experiments with differences in thawing temperature, average percentage of the results of initial test and room temperature thawing was 94.3% and the average percentage of the results of refrigerated thawing was 88.0%. After again freezing the sample, the average percentage of the second room temperature thawing result is 107.5%, and the second refrigerated thawing group is 112.7%. Both groups showed an increase from first thawing. Conclusion A comparative analysis of retesting according to differences in sample storage methods in PRA tests showed a higher correlation between the results of retesting of the refrigerated EDTA plasma. And repeated freezing and melting of plasma separation samples, regardless of temperature during defrosting, has been shown to affect results. Therefore, retest of PRA should re-collect plasma from original EDTA plasma to increase reproducibility.