• Clinical and Experimental Reproductive Medicine
• /
• v.51 no.1
• /
• pp.42-47
• /
• 2024

Objective: This study evaluated the effects of temperature and storage time on the quality and DNA integrity of freeze-dried sperm from individuals with normozoospermia. Methods: Normal sperm samples from 15 men aged 24 to 40 years were studied. Each sample was divided into six groups: fresh, freezing (frozen in liquid nitrogen), freeze-dried then preserved at room temperature for 1 month (FD-1m-RT), freeze-dried then preserved at room temperature for 2 months (FD-2m-RT), freeze-dried then preserved at 4 ℃ for 1 month (FD-1m-4 ℃), and freeze-dried then preserved at 4 ℃ for 2 months (FD-2m-4 ℃). The morphology, progressive motility, vitality, and DNA integrity of the sperm were evaluated in all groups. Results: In all freeze-dried groups, sperm cells were immotile after rehydration. The freeze-dried groups also showed significantly less sperm vitality than the fresh and frozen groups. Significantly more morphological sperm abnormalities were found in the freeze-dried groups, but freeze-drying did not lead to a significantly higher DNA fragmentation index (DFI). The DFI was significantly higher in the FD-2m-RT group than in the other freeze-dried groups. Conclusion: The freeze-drying method preserved the integrity of sperm DNA. The temperature and duration of storage were also identified as factors that influenced the DFI. Accordingly, more research is needed on ways to improve sperm quality in the freeze-drying process.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.3
• /
• pp.909-914
• /
• 2024

This study suggests a quantitative evaluation of transfer learning, which is widely used in various AI fields, including image recognition for robot vision. Quantitative and qualitative analyses of results applying transfer learning are presented, but transfer learning itself is not discussed. Therefore, this study proposes a quantitative evaluation of transfer learning itself based on MNIST, a handwritten digit database. For the reference network, the change in recognition accuracy according to the depth of the transfer learning frozen layer and the ratio of transfer learning data and pre-training data is tracked. It is observed that when freezing up to the first layer and the ratio of transfer learning data is more than 3%, the recognition accuracy of more than 90% can be stably maintained. The transfer learning quantitative evaluation method of this study can be used to implement transfer learning optimized according to the network structure and type of data in the future, and will expand the scope of the use of robot vision and image analysis AI in various environments.

• Korean Journal of Animal Reproduction
• /
• v.22 no.4
• /
• pp.349-357
• /
• 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 Poultry Science
• /
• v.40 no.3
• /
• pp.171-178
• /
• 2013

The purpose of this study was to evaluate the sperm viability, normal acrosome and mitochondrial activity in the frozen-thawed fowl semen by different cryoprotectants. The experiment was carried out on 10 sexually adult roosters of Ogye. The semen was collected twice a week and pooled semen was diluted 1:1 EK extender containing no cryoprotectant at $5^{\circ}C$. After equilibration for 30 minutes, diluted chicken semen was diluted 1:1 extender containing either 7% dimethylacetamide (DMA), 7% dimethylformamide (DMF) or 7.5% methylacetamide (MA) at final concentration and was put in 0.5 mL plastic straws and frozen for 30 minutes by exposure to liquid nitrogen vapor 4 cm above the surface of liquid nitrogen, followed by plunging into liquid nitrogen. Frozen semen was thawed in water bath at $5^{\circ}C$ for 2 minutes. For cytometric analysis, the frozen-thawed semen was diluted with EK extender to a final concentration of 90 million spermatozoa per mL. Sperm membrane integrity was evaluated as SYBR-14 and propidium iodide (PI). Acrosome integrity was assessed with fluorescein isothiocyanate-labeled PSA and PI. The percentage of mitochondrial function was estimated by using Rhodamine123 (R123) and PI. In conclusion, freezing rooster semen by using 7% DMF as cryoprotectant was significantly highest in rates of survival and mitochondrial function while its rate of damage of acrosome was significantly lowest. As a result, DMF is the cryoprotectant that has the lowest influences on sperm membranes and acrosome integrity. Therefore it could be used for freezing method of animal genetic conservation method for poultry diversity.

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

• Korean Journal of Animal Reproduction
• /
• v.23 no.2
• /
• pp.141-148
• /
• 1999

This study was to test whether the viability of bovine hatched blastocysts (HBs) can be maintained after vitrification and thawing. The HBs were produced in vitro at Day 9 and Day 10 after IVF, and they were classified to small (S-HBs; ø$\leq$300 ${\mu}{\textrm}{m}$) and large(L-HBs; ø＞300 ${\mu}{\textrm}{m}$) on the basis of embryo diameter using eyepiece micrometer. As freezing solution, we used EFS35 which consisted of 35% ethylene glycol (EG), 18% ficoll, 0.3 M sucrose and 10% FBS added in mDPBS. Vitrification was taken by two-step method, the HBs were equilibrated in 10% EG for 5 minutes and then shortly exposed in EFS35 and plunged into L$N_2$for 30~45 sec. After thawing, the survival rates were assessed by the re-expansion of the blastocoel during 2 h and 16 h of culture. The results obtained in these experiments were summarized as follows; 1) When the blastocysts(40.8%) recovered at Day 8 after IVF were further cultured for 24 h(Day 9 after IVF) and 48 h(Day 10 after IVF), the rates of HBs were 20.5% and 6.7%, respectively. Also, the total cell number of HBs on Day 9 was significantly higher than that of HBs on Day 10 (p＜0.01). 2) When the effects of freezing solution to the survival of Day 9 L-HBs were examined, the rate of vitrified group (75.7%) was significantly lower than 100% of control and exposed group(p＜0.05). 3) When the survival rates of vitrified HBs according to size and developmental age were examined, the data of L-HBs (75.5%) and S-HBs(63.6%) on Day 9 were slightly higher than those of L-HBs(64.3%) and S-HBs(60.7%) on Day 10. 4) Also, when the in vitro survival of Day 9 HBs was evaluated under different culture condition after thawing, the result in culture medium only (79.3%) was significantly higher than 43.2% in co-culture group (p＜0.05). These results demonstrated that bovine HBs can be successfully cryopreserved by two-step vitrification method using EFS35.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.200.2-200.2
• /
• 2010

This study was carried out in order to reduce the amount of underground water which is used in the water curtain system for retaining heat. To proceed to the research, two plastic green houses of water curtain system were installed. One was equipped of internal small tunnel for keeping warm air in the interior of the house. Then the internal small tunnel for keeping warm air was fitted with PVC duct of 50cm in diameter filled with subsurface water. Storing surplus solar energy in the water filled in PVC duct was the method used to this house. Another was installed with FCU in the middle of the house, and was fitted a circulation motor in water tank for heat storage which was operated from 10 a.m. to 4 p.m. in order to interchange heat with FCU. The latter was installed with four FCUs which has a capacity of 8000kcal per hour. Consequently about 5 degrees celsius could be maintained in the interior of the internal small tunnel for keeping warm air with the external temperature of more than minus 5 degrees celsius. It appeared that the alteration of an internal temperature of the house was flexible depending on the sunlight during daytime. It happened that to prevent the water from freezing, mixing antifreezing liquid in the flowing water of FCU or changing the operating method of FCU was a suitable measure. Also, in order to use the surplus solar thermal energy on plastic green house of water curtain system efficiently, storing the surplus heat during daytime simultaneously finding a method of using water curtain systematic underground water happened to be important. As a result of this research, when the house's interior temperature is below zero the operation of FCU appeared to be impossible. Therefore when supposed that the amount of water used in the house is 150~200ton for stable operation of FCU, using the system mentioned in the above research happened to be appropriate of reducing the amount of subsurface water from 80% to 100% when maintaining the interior of internal small tunnel's temperature for keeping warm air of 5 degrees celsius at the extreme temperature of minus 5 degrees celsius.

• Journal of the Korean Geosynthetics Society
• /
• v.15 no.3
• /
• pp.57-66
• /
• 2016

In this study, to prevent possible collapse caused by hydraulic or mechanical instability, liquid nitrogen injection method is developed and implemented at the tip of drilling auger of steel pipe propulsion tunneling. In this study, 1/5-scale model auger and sand chamber were manufactured. The prototype diameter of steel pile (or casing) is assumed about 1,000 mm. For the frictional sandy soils and plastic weathered soils, liquid nitrogen injection methods were tested varying water contents of the soils. For the induced hydraulic instability, the ground near the drilling auger was frozen within approximately 5 minutes preventing mechanical collapse and water infiltration. Securing stability of steel pile propulsion tunneling using liquid nitrogen was much more effective for which the water content of the soil somewhat exceeds the optimum water content.

• Clinical and Experimental Reproductive Medicine
• /
• v.19 no.2
• /
• pp.143-152
• /
• 1992

The present experiments were focussed to modify a short slow-cooling protocol used for freezing of early stage embryo(Testart et al., 1986) and also to apply the modified method for the cryopreservation of hamster oocytes with Zona or without. The protocol was modified by changing the 4-step equilibration into 1-step and the 1-step thawing into 2-step. The oocytes were added in 1.5M PROH and 0.1M Sucrose, seeded at $-7^{\circ}C$, slow cooled($0.3^{\circ}C$/min) to $-30^{\circ}C$ before plunging to $-196^{\circ}C$. The oocytes were thawed at $23-25^{\circ}C$ air(20sec/150sec) and/or 33-35 water(10sec). The survival of the frozen-thawed oocytes was determined by morphologic criteria and their fertilizing ability was also estimated by Sperm Penetration Assay(SPA) system(Chang et al, 1990) using fertile men semen sample. One-step equilibration showed slightly higher survival rate(83.9% vs. 71.0%) and fertilization rate(83.9% vs. 71.0%) compared with four-step(p>0.05). And two-step thawing(air & water exposing) of oocytes frozen after 1-step equilibration showed significantly higher survival rate(96.3%) than one-step thawing at air(85.2%) or water(65.0%) only(p<0.05). Therefore, by the modified method(l-step equilibration & 2-step thawing), Zona-intact(ZI) and Zona-free(ZF) oocytes were frozen and thawed. ZI-oocytes showed significantly higher survival rate(95.4%, 308/323 vs. 67.6%, 240/355) than ZF-oocytes(P<0.01). But the survival of ZF-oocytes was as high as ZI-oocytes in fourteen of twenty-four replicates. ZI-oocytes was also significantly higher fertilization rate($92.4{\pm}8.9%$ vs. $63.7{\pm}18.5%$) and higher mean number of penetrated sperm($6.2{\pm}4.2$ vs. $3.9{\\pm}3.3$) than ZF-oocytes, but not higher than control(fresh oocytes;$99.3{\pm}2.4%$, $8.4{\pm}4.2$)(P<0.001). Conclusively, this modified method will contribute to freeze effectively the hamster oocytes for simplifing of the logical consideration of performing SPA and also to freeze the human and other animal oocytes.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.5
• /
• pp.76-87
• /
• 2014

Today the energy consumption of ICT networks is about 10% of the worldwide power consumption and is predicted to increase remarkably in the near future. For this reason, this paper studies energy saving strategies assuring the network-level QoS. In the strategies, the energy consumption of NIC(network interface card) on both endpoint of links decreases by selecting links and making them sleep when the total traffic volume of the IP network is lower than a threshold. In this paper, we propose a heuristic routing algorithm based on so-called delegating/delegated routers, and evaluate its characteristics using computer simulation considering network-level QoS. The selection of sleep links is determined in terms of the number of traffic paths (called min_used path) or the amount of traffics(called min_used traffic) through those kinks. To our experiment, the min_used traffic method shows a little better energy saving but the increased path length compared to the min_used path method. Those two methods have better energy saving characteristics than the random method. This paper confirms that the delegating/delegated router-based routing algorithm results in energy saving effects and sustains network-level QoS in IP networks.