• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.104-104
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• 2002

This study was performed to find out the optimal larval stage among trochophore, D-shaped and umbo stage larvae and the desirable protective additive such as fructose, glucose, sucrose and trehalose with cryoprotectant for cryopreservation of surf clam, Spisula sachalinensis larvae. Dimethyl sulfoxide and ethylene glycol were used as cryoprotectant and each cryoprotectant was made to 2.0 M with previous protective additives. The larvae were immersed in the preparations waited for 15 minutes to reach equilibration, and then frozen in a program freezer (-35$^{\circ}C$) and liquid nitrogen (-196$^{\circ}C$). The freezing rate of 1.0$^{\circ}C$ /min. was used for cryopreservation of trochophores before seeding temperature (-12$^{\circ}C$). The survival rate of frozen-thawed larvae increased as larval developing and that of umbo stage larvae was the highest as 96.1 ${\pm}$ 1.0%. The presence of lower concentration of disaccharides as sucrose or trehalose significantly enhanced survival rate when mixed with cryoprotectants (P<0.05). The results of our study indicate that desirable developmental stages of larvae and protective additive for cryopreservation are the umbo stage larvae and 0.2 M sucrose, respectively.

• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.231-235
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• 2010

The effects of various natural antioxidant sources on oxidation of olive flounder (Paralichthys olivaceus) and fish diet during storage was determined. Juvenile fish were distributed among 18 flow-through tanks (40 fish per tank). Six experimental diets were prepared in triplicate: control (CT), antitox (AT), green tea extract (GE), fig extract (FE), Haeroc product (HP) and by-product of green tea (BG). The experimental diets were stored at two temperatures: room temperature ($26.8^{\circ}C$) for 14 days and frozen ($-30^{\circ}C$) for 16 weeks. Thirty fish were sampled from each tank at the end of the 8-week feeding trial. Whole bodies of fish were homogenized and stored in a home freezer ($-9.6^{\circ}C$) for 24 weeks. Acid values (AVs) and peroxide values (POVs) of the diets and frozen fish during storage were monitored. AVs of the experimental diets tended to increase with the storage period except for that of the HP diet at room temperature. POVs from FE, CT, and BG diets peaked at day 7 and then decreased through the remainder of the experiment. AVs of the experimental diets and fish increased with time at $-30^{\circ}C$ and $-9.6^{\circ}C$. Results of this study show that by-products of green tea and Haeroc product seem to have potential as antioxidants in fish feed to inhibit oxidation of both the feed and fish during storage.

• The Korean Journal of Pain
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• v.12 no.1
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• pp.8-15
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• 1999

Following peripheral nerve injury, rats will show a tactile allodynia and hyperalgesia. But the mechanism of allodynia is still obscure. The present studies, using rats rendered allodynia by loosely constrictive ligation of the common sciatic nerve (Bennett Model) and tight ligation of L5 & L6 spinal nerve (Chung Model), aimed to investigate the changes of metabotrophic glutamate receptor type 5 on the development of tactile allodynia. Male Sprague-Dawley rats (130~200 g) were anesthetized with halothane, the rats were randomly divided into one of these three groups, Group 1 (Sham operation), Group 2 (Bennett model) and Group 3 (Chung model). Seven days after surgical procedure, the animal was reanesthetized and decapitated. The spinal cord was quickly removed and stored at deep freezer for polymerase chain reaction (RT-PCR). In Group 2&3, rats showed that tactile allodynia checked by up-down method with calibrated 8 von Frey hair. The level of gene expression of mGluR5 mRNA was significantly increased in group 2 and 3. These increases was significantly different from sham operation, group 1. It was also showed that the increasing patterns of group 2 and 3 in the gene expression were similar correlation with the results of the threshold for tactile allodynia on von Frey hair test. Even though there were some differences between Bennett model and Chung model, these results suggested that mGluR5 had partly attributed to making a tactile allodynia from these models.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.372-378
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• 2000

The cell culture of Angelica gigas Nakai producing decursin derivatives and immunostimulating polysaccharides was preserved in liquid nitrogen after pre-freezing in a deep freezer at -70$^{\circ}C$ for 480 min. The effects of the cryoprotectant and pretreatment before cooling were investigated to obtain the optimal procedure for cyropreservation. When compared to mannitol, sorbitol, or NaCl with a similar osmotic pressure, 0.7 M sucrose was found to be the best osmoticum for the cryopreservation of A. gigas cells. In the pre-culture medium, the cells in the exponential growth phase showed phase showed the best post-freezing survival after cryopreservation. A mixture of sucrose, glycerol, and DMSO was found to be an effective cryoprotectant and a higher concentration of the cryoprotectant provided better cell viability. When compared with the vitrification, the optimum cryopreservation method proposed in this study would seem to be more effective for the long-term storage of suspension cells. The highest relative cell viability established with the procedure was 89%.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.168-173
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• 2012

The objective of this study was to investigate the problems and benefits associated with the implementation of HACCP on livestock product of plants in Korea. The survey was carried out by randomly selecting 115 HACCP accredited meat processing plants, all across the country. A total of 105 complete responses were selected for analysis. The results were as follows: approximately 60% of the respondents employed less than twenty workers. The average period of operating HACCP system was 3.4 years. The respondents replied that the major incentive to implement the HACCP system was to improve hygiene management ability. More than half of the respondents (59.05%) claimed that the implementation of the HACCP system cost less than 400 million won, and the highest investment in terms of cost was the freezer/refrigerator. In the preparation period taken to implement the HACCP system, the 6-12 mon category had the highest percentage (55.24%). Most respondents replied that there was an increase in the customer satisfaction, plant image and turnover, after HACCP implementation (p<0.05). A total of 98.09% of respondents had the opinion that their plant workers had improved in their understanding of food hygiene by HACCP implementation (p<0.05). Approximately 79% of respondents indicated that customer complaints decreased, as a result of HACCP implementation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.12
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• pp.641-646
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• 2013

The purpose of this study is to improve the cooling performance of single and cascade refrigeration systems using thermoelectric modules. The system consists of a heat sink, fan, and thermoelectric module. The operating parameters considered in this study include power distribution between the first- and second-stage thermoelectric modules, air flow, and variable condensing unit. The cooling capacity increased with decreases in the temperature difference between hot and cold surfaces, but decreased with increases in the condensing temperature. The COP decreased with increasing electric power of the thermoelectric module because of the increased Joule heat. The cooling performance improvement using the thermoelectric module is represented by the freezer temperature.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.1-6
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• 2004

This paper shows the study on the design and another applications of the spray-freeze dryer for the production of valuable material powders. Powder production and handling has been an integral part of material extracting processing and pharmaceutical processing because of the wide use of oral dosage forms. There are a few commonly used powder preparation methods including mechanical milling, precipitaion, spray drying, freeze drying, and so on. In general, methods available for preparing inhalation powders are limited due to certain inhalation powder's sensitive nature to the processing environments. This is particularly true for preparing dry powder aerosols where the aerodynamic particle size($<5{\mu}m$) and the size distribution are pivotal. Supercritical fluid antisolvent and spray freeze drying have recently emerged as promising techniques for producing powders for use in microcapsulation. However, the aerosol applications of these powders are yet to be explored. The purpose of this study is to test the feasibility of using spray freeze-dried valuable material powders for aerosolization.

• Fashion & Textile Research Journal
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• v.12 no.4
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• pp.513-522
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• 2010

The aim of this study is to investigate the actual state for the development of the thermally comfortable uniform for workers on a low temperature storage. Observation, interview and survey were executed focusing on the environment, clothing, and human factors which have effects on the comfort of workers. Of 400 distributed, 253 questionnaires were analyzed through descriptives, frequency, ANOVA, t-test, multi-response analysis, correlation analysis with SPSS 12.0. The results are following. Coming and going between a selling area and cold storages, the workers showed to experience a big temperature gap. They indicated to feel cold on face and hands which were not covered by clothing and have got sick because of low temperature. The workers wanted the uniform made of functional fabrics, especially heat insulation fabrics. Female workers rather than male workers, the older, and the longer their working period were, the more uncomfortable they revealed to feel. The workers who works on the daily products part or mainly on the freezer appeared to feel cold more than any other workers. In conclusion, it was found that the uniform which consider steady state and unsteady state heat transfer together must be developed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.7
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• pp.513-519
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• 2011

The object of this study is to investigate the performance characteristics of refrigerators using a single-circuit multi cycle and a bypass two-circuit multi cycle. Each refrigeration cycle was tested by varying secondary fluid mass flow rate and temperature. Based on the experimental data, the optimum refrigerant charge was 48 g and the COP at the optimum secondary fluid mass flow rate was 1.53 for the single-circuit multi cycle. For freezer(F)-only mode, both the single-circuit multi cycle and the bypass two-circuit multi cycle were operated at overcharge conditions, resulting in an increase of the secondary fluid mass flow rate. The maximum COPs of the single-circuit multi cycle and the bypass two-circuit multi cycle were 1.22 and 1.35, respectively. The COP increased by 10.7% with the application of the bypass two-circuit multi cycle.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.73-79
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• 2002

To investigate the usability of frozen canine embryos for embryo transfer in the dog, 19 donors, 3 recipients, and 6 male dogs were used for the experiment. Natural mating or artificial insemination was performed for breeding the bitches in natural estrus. Vaginal smear test along with progesterone titre test were performed to detect the appropriate mating time and the bitches were bred twice during 3-6days following LH surge. Embryo collection was done on 8, 9-11, 12-13 days after the second mating to collect morula and blastocyst. Embryos were frozen using a programmable freezer and preseued in LNE tank. Embryos were thawed in 37$^{\circ}C$ water for 15 seconds and transferred into each uterine horn within 30 minutes. Embryos were collected from 13 bitches of 19 donors(68.4%) and the collected embryos were from between 9 and 13 days after 2nd mating. Embryos were produced both by natural mating(60.0%, 9115) and AI with frozen semen(100.0%, 4/4). Embryos were collected from the donors weighed between 2.5 and 30 kg and their age was from 1.5 to 3 years. 52 embryos were collected from 13 donors and the mean number of embryos was four. The stage of embryos was from 2-cell to gastrula and morulae were colledted mostly from 10 to 11 days after 2nd mating. Embryos were collected evenly from each uterine horn and the rate of embryo collection for the number of corpus luteum was 83.9%. Embryos were transferred to 3 recipients(morula 8, blastocyst 1, gastrula 8), however, no offspring was produced.