• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.349-357
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• 1998

This study was to investigate whether the viability of Hanwoo IVM/IVF/IVC blastocysts was maintained after vitrification and thawing. In vitro produced Hanwoo blastocysts were vitrified by two-step method: equilibrated in EG20 for 3 min, and then exposed in EFS40 ［40% ethylene glycol (EG), 18% ficoll and 10.26% sucrose in mDPBS containing 10% FBS ］and vitrified in L$N_2$for 30 - 45 sec. After thawing, in vitro survival was assessed as the re-expanded and hatched rates at 24 hand 48 h, respectively. The results obtained in these experiments were summarized as follows: From the 12 replicates, 52.5% of Hanwoo blastocysts were produced in vitro at day 7 after IVF. When the effects of freezing solution to the embryo survival were examined, there is no significant toxicity in exposure (100.0, 73.8%) compared to that af control group (100.0, 87.0%). However, when embryos were vitrified, high survival (86.2, 55.4%) was obtained although it was significantly lower than those of exposure and control group (p＜0.05). When the in vitro survival of vitrified embryos according to developmental stage and culture day were examined, it showed that more advanced embryo stage exhibited a significantly higher survival rate irrespective of culture day (p＜0.05). Also, even in the same development stage, the in vitro survival of day 7 embryos (re-expanded: 75.0~87.5%, hatched: 21.4~66.7%) was higher than those of day 8 embryos(re-expanded: 58.6~78.3%, hatched: 10.3~52.2%). Therefore, these results suggested that in vitro produced Hanwoo blastocysts can be successfully cryopreserved by simple two-step vitrification method using EFS40 freezing solution, particularly at the expanded and early hatching blastocyst stage regardless of embryo culture duration (day 7 or day 8 after IVF).

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.862-870
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• 1998

This study shows the application of Ci-ELISA method for monitoring the denaturation of myosin by the frozen treatment in order to differentiate thawed beef from chilled. Hanwoo M.Semitendinosus (n=25) was treated under the two different frozen process as follows; simple frozen treatment (Exp-1) at 4 different temperatures, -10, -20, -50 and $-80^{\circ}C$, respectively, and repeated thawing-refreezing treatment (Exp-2) stored at 4 different temperatures, -10, -20, -50 and $-80^{\circ}C$, respectively. Antibodies (Abs) were produced from rabbits immunized with myosin whole molecule (MWM) isolated from beef round, heavy meromyosin S-1 (S-1) and light meromyosin (LMM) prepared by digestion of MWM. Each immunoglobulin G (IgG) was separated from antiserum. At 6 month storage, IA of anti-MWM IgG for myosin was decreased to 32.67, 32. 23, 51.52 and 34.27% in Exp-1 and to 14.82, 15.61, 25.3 and 23.7% in Exp-2 at -10, -20, -50 and $-80^{\circ}C$, respectively (P<0.05). In Exp-1, the reactivities of anti-LMM IgG were decreased to 25.12, 21.42, 49.05 and 28.96%, and those of Exp-2 were to 11.88, 9.56, 20.63 and 12.64% at -10, -20, -50 and $-80^{\circ}C$, respectively, at 6 times thawing (P<0.05). Conclusively, myosin was denaturated by freezing treatment and LMM or myosin rod part might have suffered from more extreme demage than HMM S-1, and samples at $-50^{\circ}C$ were slightly injured less than others by freezing treatment.

• Development and Reproduction
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• v.20 no.3
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• pp.219-225
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• 2016

Most of the commercial devices for vitrification are directly immersed into the warming solution (WS) for increasing of warming rate. However, the previous modified cut standard straw (MCS) which has reported is difficult to immerse into the WS. The aim of this study was to investigate whether the long cut straw (LCS) could be useful as a stable tool for vitrified-warmed human blastocysts. A total of 138 vitrified-warmed cycles were performed between November 2013 and November 2014 (exclusion criteria: women ${\geq}38$ years old, poor responder, surgical retrieval sperm, and severe male factor). The artificial shrinkage was conducted using 29-gauge needles. Ethylene glycol and dimethyl sulfoxide (7.5% and 15% (v/v)) were used as cryoprotectants. Freezing and warming were conducted using the LCS tool. The cap of LCS was removed using the forceps in the liquid nitrogen ($LN_2$) and then directly immersed into the first WS for 1 min at $37^{\circ}C$ (1 M sucrose). Only re-expanded blastocysts were transferred after it was cultured in sequential media for 18-20 h. A total of 294 blastocysts were warmed, and all were recovered (100%). Two hundred eighty-five embryos were survived (96.9%). The vitrified-warmed blastocysts of all patients were transferred without any cancellation. We were able to achieve a reasonable implantation (24.2%), following by clinical pregnancy (36.2%), which then continued to ongoing pregnancy (36.2%), and live birth (31.2%). Using LCS is achieved the acceptable rates of survival, pregnancy and live birth. Therefore, the LCS could be considered as a stable and simple tool for human embryo vitrificaton.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.234-234
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• 2017

Recent abnormal weather, especially continued rainfall during sowing season causes difficulty in proper sowing of wheat and delayed sowing after November 15 is concerned about freezing damage during winter, resulting in reduction of wheat yield. To correspond government policy of crop sufficiency improvement and produce and supply raw wheat and barley steadily, expansion of cultivation area is necessary and spring sowing of wheat is required. To obtain basic information on the improvement of spring sown wheat and barley production, comparison and path coefficients analysis was conducted for yield and yield related components from autumn and spring sown wheat and barley. Path analyses were known as very useful in clarifying the effects of yield components on grain yield formation, which were not accurately reflected in simple correlation anaylses. Most cultivated 5 wheat and 9 barley cultivars were sown on October and February at Cheon-ju province according to standard sowing method. For the spring sowing of wheat and barley, the varieties having vernalization degree I~III are seeded in the mid of February and seeding rate is 200~250kg/ha which is increased by 25% than autumn sowing. N-fertilizer of 95 kg/ha and the same amount of P, K dressed in autumn are applied at once as basal fertilizer. The magnitude of direct effect in each yield components on yield was in sequence as follows. In autumn wheat, grain number per $spike{\geq}$ the number of spike per $m^2$>1000-grain weight and in spring wheat, grain number per $ spike{\geq}the$ number of spike per $m^2$> 1000-grain weight. In autumn naked barley, 1000-grain weight> the number of spike per $m^2$, grain number per spike and in spring barely, the number of spike per $m^2$> grain number per spike > 1000-grain weight. In autumn covered barley, grain number per spike>the number of spike per $m^2$ and in spring coverd barley, the number of spike per $m^2$> grain number per spike, 1000-grain weight. In autumn malt barley, the number of spike per $m^2$>1000-grain weight and in spring malt barley, the direct effects of three yield components were similar. According to the path analysis of yield components for spring sown wheat and barley, it was suggested that adequate number of spike per $m^2$ was most important factor for yield increase.

• Archives of design research
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• v.11 no.1
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• pp.237-244
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• 1998

Rapid prototyping is an efficient method to evaluate the usability of electric home appliances. However, the use of rapid prototyping method in usability tests has not been sufficiently validated. The purpose of this study was to validate computer-generated prototypes whether they can replace real products in usability tests. The control-display panel of a refrigerator was selected for this study. Sixteen female subjects participated in a between-subjects experiment: Eight subjects of them used the real refrigerator while others used the computer-generated prototype of the refrigerator. The difference between the refrigerator and the prototype was analyzed in terms of task failure rate, task completion time, and the number of buttons pressed for three typical tasks: clock setting, selecting an operation mode for refrigerating room, and selecting an rapid freezing mode. The results of a non-parametric statistical test showed that the prototype was not significantly different from the real refrigerator. Therefore, the rapid prototyping technique can be applied to the usability tests for the simple electric home appliances such as the refrigerator.

• Korean Journal of Animal Reproduction
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• v.15 no.1
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• pp.49-57
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• 1991

This study was carried out to investigate the effect of equilibration time, precooling and straw loading method on the post-thaw survival rates of mouse embryos cryopreserved by vitrification method. The effect of the vitrification procedure on the damage of the embryos was also examined by the straining of nuclei using Hoechst 33342. The results obtained were summarized as follows; 1. The equilibration in Medium-1 for 10 minutes was considered to be the optimum equilibration time. Embryos equilibrated in Medium-1 for 10 minutes(81.0%) showed significantly(P<0.05) higher survival rates than those equilibrated for 5 minutes(40.0%) or 15 minutes(74.1%). 2. The survival rate of embryos cryopreserved using the double Medium-2 column(81.0%) was significantly(P<0.01) higher than that using the single Medium-2 column, whish was considered to be due to the double Medium-2 column method being more reliable for preventing contamination of diluent solution of 1M sucrose. 3. The survival rate of compacted morula stage embryos cryopreserved with the precooled and non-precooled Medium-2 was not significantly(P<0.05) different. 4. The number of blastomeres of embryos at late blastocyst stage after culture of mouse morulae for 24 to 28hours was significantly(P<0.05) decreased by freezing embryos using vitrification(53.3${\pm}$1.6 vs 41.4${\pm}$1.5), which was considered to be due to the damage of embryos during vitrification and the delay of embryo development by handling in vitro. 5. The vitrification procedure is considered to be a very simple and efficient method for cryopreservation of embryos at early developmental stage.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.187-192
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• 2022

The repeated monthly or weekly subculture of plant callus is labor intensive and increases the risk of somaclonal variation from the parental callus line. The most effective method for preserving plant callus is cryopreservation, which involves storage in liquid nitrogen. However, this method cannot be applied to the callus of different plant species in the same manner, so it is difficult to develop a standardized cryopreservation method. In addition, the survival rate of the frozen callus after thawing and the regeneration rate after survival are uncertain. Therefore, it is necessary to develop a method to extend the subculture interval of plant callus in an active state. In this study, active plant calli of various species without freezing was incubated at 15℃ for 4 to 12 weeks without subculture. After 12 weeks, 8 lines of plant callus grew less than 2-fold when cultured at 25℃, but at least 2 times as much when cultured at 15℃. Moreover, total antioxidant activity did not differ significantly between plant callus recovered at 25℃ after culturing at 15℃ or at 25℃. These results show that the subculture interval can be extended at a temperature of 15℃ without need for modified medium composition or additional processes. In addition, positive results in all calli of several plant species are expected to reduce labor as well as somaclonal variation by increasing the subculture.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.281-288
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• 2001

The relationships between the growths of Abies koreana W. and climatic factors were analyzed by the use of tree-ring analysis at the subalpine belt of Mt. Halla National Park. The four cores were extracted from each 21 trees at north-facing slope (1,900m a.s.1.). The site chronology was established on the periods from 1912 to 1999. The growth of A. koreana was very poor, in particular in the years of 1982, 1988 and 1996. Simple correlation was employed to analyze the relationship between the growth of A. koreana and climatic factors. The result of simple correlation indicates that the growth of A. koreana represent positive correlations both with the mean temperatures of April and previous November, and the precipitation of previous December and January. The presence of large number of frost-damaged scars in the individual trees of A. koreana implies that local freezing temperature conditions at Mt. Halla have occurred in 1964, 1965 and 1966. The correlations between the fir chronology SOI(Southern Oscillation Index) of previous January, February and November were significantly positive. The growth ratio of A. koreana demonstrates that this species is sensitive to seasonal variations. As the winter temperature rises, the growth ratio of A. koreana decreases, on the other hand, the increase of autumn temperature accelerates the growth ratio of A. koreana. The growth decline of A. koreana was observed from 51 cores out of the 54 cores, and the overall growth declines have initiated at 1978, 1982 and 1988. Distinct growth decline of A. koreana in the range of 70% is noticed at 34 cores out of the 51 cores. The decline of, A. koreana growth appears to be related to the winter temperature which has increased since mid-1970s.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.119-126
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• 1996

This study was carried out to determine the optimal condition for successful and efficient c cryopreservation of zygotes, 1-cell embryos, using EFS40 which was 40% (v/v) ethylene glycol diluted in DPBS medium containing 30% Fic-oll (w/v) and 0.3 M sucrose. After mouse zygote produced by IVF was vitrified by two freezing methods, the post-warming survival rates of 1-cell zygotes were assessed as cleavage to the 2-cell stage and development into the hatching blastocysts at 5 day. In the one-step method, when embryos were directly exposed to the vitrification solution at 25$^{\circ}C$ for 1 min., survival and development rates of zygotes were 85.5% and 31.9% In the two-step method, embryos were equilibrated with a dilute 20% EG for 1, 3, 5 min. before 1 min. exposure to EFS40, re-spectively. However, the rates of development (17.7, 3.3, 0%) were lower than that of one-step method. The highest survival rate (95.9%) was obtained by one-step method which exposes embryos in EFS40 for 30 sec. In this condition, 63. 8% of cleaved 2-cell developed into hatching blastocysts. In the cell number of Total and ICM using differential labelling technique, there are no significant differences in the cell number of Total and ICM between blastocysts devel oped in vitrified-thawed embryos (63.2${\pm}$16.9, 1 13.5${\pm}$4.0) and control balstocysts (54.0${\pm}$15.2, 1 12.3${\pm}$4.6). Therefore, these results show that mouse zygotes can be successfully cryopreserved by a simple vitrification method although developmental rates of vitrified embryos were reduced. In conclusion, this proposed vitrifi cation procedures can be useful in the cryopreservation of mouse IVF zygotes.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.243-248
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• 2017

Sea ice which is an important component of the global climate system is being actively detected by satellite because it have been distributed to polar and high-latitude region. and the sea ice detection method using satellite uses reflectance and temperature data. the sea ice detection method of Moderate-Resolution Imaging Spectroradiometer (MODIS), which is a technique utilizing Ice Surface Temperature (IST) have been utilized by many studies. In this study, we propose a simple and effective method of sea ice detection using the dynamic threshold technique with no IST calculation process. In order to specify the dynamic threshold, pixels with freezing point of MODIS IST of 273.0 K or less were extracted. For the extracted pixels, we analyzed the relationship between MODIS IST, MODIS $11{\mu}m$ channel brightness temperature($T_{11{\mu}m}$) and Brightness Temperature Difference ($BTD:T_{11{\mu}m}-T_{12{\mu}m}$). As a result of the analysis, the relationship between the three values showed a linear characteristic and the threshold value was designated by using this. In the case ofsea ice detection, if $T_{11{\mu}m}$ is below the specified threshold value, it is detected as sea ice on clear sky. And in order to estimate the performance of the proposed sea ice detection method, the accuracy was analyzed using MODIS Sea ice extent and then validation accuracy was higher than 99% in Producer Accuracy (PA).