• Korean Journal of Agricultural Science
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• 제20권2호
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• pp.181-188
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• 1993

Frozen korean traditional poultries(Manyker, Korean native fowl, Ogol fowl and Pheasant) were thawed at $5^{\circ}C$, and $20^{\circ}C$ in the air, and using a microwave oven. Effect of thawing methods on the quality of Korean poultry was investigated. The pH of the poultry muscle was lowered after thawing in all treatments. The pH of the muscle thawed by microwave oven was the lowest. The quantity of drip released after thawing was the least in a microwave thawing. The quantity of drip in Maniker and Pheasant was loss than Ogol fowl. The relationship between pH and water binding capacity showed highly significant, and the drip quantity after thawing increased as the pH decreased. Leg muscle has higher strength than breast muscle in all the Korean poultry. Shear strength of all the poultry muscle showed closely relative related to the pH. As the pH lowered, the shear strength of the muscle was also decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• 제45권2호
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• pp.230-238
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• 2016

This study examined the effects of freezing and thawing conditions on quality of Hanwoo bottom round. The beef samples were frozen by air blast freezing at $-20^{\circ}C$ or ethanol immersion freezing at $-70^{\circ}C$ and then stored at $-20^{\circ}C$ for 10 days. After 10 days of storage, the frozen samples were thawed with air blast thawing at $4^{\circ}C$ or water immersion thawing at $4^{\circ}C$ and subjected to subsequent analyses of drip loss, water holding capacity, thiobarbituric acid reactive substance (TBARS), volatile basic nitrogen (VBN), total aerobic bacteria, and microstructure. Drip loss significantly increased in samples treated with air blast freezing compared to ethanol immersion freezing, whereas freezing and thawing processes had no significant impact on water holding capacity of the samples. Thawing conditions had a much stronger influence on the TBARS and VBN of the samples than freezing conditions. There was no significant difference in the population of total aerobic bacteria among the four samples subjected to one freeze-thaw cycle. In addition, to analyze the effects of freeze-thaw cycle on the quality of beef, three freeze-thaw cycles were performed during storage. Multiple freeze-thaw cycles increased drip loss, TBARS, and VBN and decreased water holding capacity, accelerating microstructural damage. These data indicate that Hanwoo bottom round can be rapidly frozen and thawed by using ethanol immersion freezing and water immersion thawing methods with minimal impact on meat quality.

• Clinical and Experimental Reproductive Medicine
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• 제29권2호
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• pp.149-157
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• 2002

Objectives: To assess the scavenging effect of carnitine derivatives on oxidative damage to sperm during sperm processing, cryopreservation and thawing. Materials and Methods: Fresh semen samples from 20 normal healthy volunteers were collected by masturbation after at least 48 hours abstinence. After liquefaction of semen samples at room temperature, the specimens were diluted with sperm wash media (Ham's F-10, Life technologics) to a uniform density of $20{\times}10^6/ml$. L-carnitine or acetylcarnitine were added with various concentration of $0{\mu}M$, $10{\mu}M$, $30{\mu}M$ in semen sample or cryoprotectant. All specimens were cryopreservated at $-196^{circ}C$ $LN_2$ for 3 days. Sperm motility, vitality, fertilizing capacity, reactive oxygen species formation and the level of lipid peroxidation were analyzed by computer assisted semen analyzer, eosin-nigrosin stain, hypoosmotic swelling test, chemiluminescence and thiobarbituric acid method, respectively, during sperm processing, cryopreservation and thawing. Results: The sperm motility was only increased in proportion to the concentration of acetylcarnitine with no statistical significance (p>0.05). The sperm vitality was also significantly improved in proportion to the concentration of acetylcarnitine with statistical significance (p<0.05). The sperm fertilizing capacity was significantly increased in proportion to the concentration of L-carnitine and acetylcarnitine and reactive oxygen species generation and lipid peroxidation were significantly decreased with same fashion (p<0.05). On comparison of effects between L-carnitine and acetylcarnitine, acetylcarnitine was superior to L-carnitine on the improvement of sperm motility and vitality as well as the suppression of reactive oxygen species generation and lipid peroxidation. Conclusions: These results suggest that carnitine derivatives have a scavenging effect against oxidative damages during sperm processing, cryopreservation and thawing. Therefore, carnitine derivatives may be useful as an oral antioxidant in patients with male infertility due to increased ROS generation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.43-46
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• 2009

The purpose of this study is to enhance durability of concrete structures that uses this surface protecting material by carrying out the performance test of the surface protecting material of concrete, and as s result, we reached out the conclusion as follow. 1. As a result of the test measuring the stability and adhesive power of conductive film against ultraviolet, freezing & thawing, and damage from seawater that deteriorate the surface protecting material, it was turned out to meet the performance criteria specifying in the KS standard enough to gain a good evaluation to use as a surface protecting material. 2. As a result of the test identifying the neutralization-furtherance, it was assessed to be capable of protecting effectively concrete structures from carbonic acid gas by a very low depth of 0.1mm of neutralization. 3. As a result of the test identifying Penetrated Resistance Properties of chloride ion, as it was turned out to have a very low value of 819 Coulombs, it was assessed that even in the environment where the corrosion by chloride such sea environment is very affective, the film can effectively protect the concrete structure. 4. As a result of the test identifying freezing & thawing, as there was no change in reduction of mass after 400 cycle, it was assessed that the film has a good resistance against freezing & thawing. According to the results of study above, it is expected that this technology can extend its durability of concrete structure and be widely used for concrete structure through means (methods) to prevent the neutralization and damage from seawater as original purposes of the surface protecting material.

• International Journal of Highway Engineering
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• 제18권1호
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• pp.63-72
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• 2016

PURPOSES : The use of roller-compacted concrete pavement (RCCP) is an environmentally friendly method of construction that utilizes the aggregate interlock effect by means of a hydration reaction and roller compacting, demonstrating a superb structural performance with a relatively small unit water content and unit cement content. However, even if an excellent structural performance was secured through a previous study, the verification research on the environmental load and long-term durability was conducted under unsatisfactory conditions. In order to secure longterm durability, the construction of an appropriate internal air-void structure is required. In this study, a method of improving the long-term durability of RCCP will be suggested by analyzing the internal air-void structure and relevant durability of roller-compacted concrete. METHODS : The method of improving the long-term durability involves measurements of the air content, air voids, and air-spacing factor in RCCP that experiences a change in terms of the kind of air-entraining agent and chemical admixture proportions. This test should be conducted on the basis of test criteria such as ASTM C 457, 672, and KS F 2456. RESULTS : Freezing, thawing, and scaling resistance tests of roller compacted concrete without a chemical admixture showed that it was weak. However, as a result of conducting air entraining (AE) with an AE agent, a large amount of air was distributed with a range of 2~3%, and an air void spacing factor ranging from 200 to $300{\mu}m$ (close to $250{\mu}m$) coming from PCA was secured. Accordingly, the freezing and thawing resistance was improved, with a relative dynamic elastic modulus of more than 80%, and the scaling resistance was improved under the appropriate AE agent content rate. CONCLUSIONS : The long-term durability of RCCP has a direct relationship with the air-void spacing factor, and it can be secured only by ensuring the air void spacing factor through air entraining with the inclusion of an AE agent.

• Animal Bioscience
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• 제34권8호
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• pp.1375-1381
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• 2021

Objective: This study was conducted to determine the effect of freeze-thawed cycles (Fresh meat, F-T 1 cycle and F-T 2 cycles) on the quality characteristics of porcine longissimus dorsi muscle. Methods: A total of 20 three-crossbred pigs (Duroc×[Large White×Landrace]) were randomly obtained from a commercial slaughterhouse in Thailand. Muscle samples were immediately taken from 10 to 11th of the longissimus dorsi for histochemical analysis. The muscles were cut into 2.54 cm-thick chops. A minimum of 20 chops were used for each treatment (fresh meat, freeze-thawed 1 and 2 cycles). Individually chops were packaged in polyethylene bags and frozen at -20℃ for 6 months followed by thawing in refrigerator at 4℃ for 24 h (the 1st freeze-thawed cycle). The freeze-thawed procedure was repeated for two cycles (the 2nd freeze-thawed cycle). Thawing loss, shear force value, citrate synthase activity and muscle fiber characteristics were determined on the muscles. Results: Results showed that increasing of freeze-thawed cycle increased the thawing loss (p<0.01) and citrate synthase activity (p<0.001). Shear force value of fresh meat was higher than freeze-thawed 1 and 2 cycles (F-T 1 cycle and F-T 2 cycles). Freeze-thawed cycles affected muscle characteristics. Muscle fiber area and muscle fiber diameter decreased with an increasing number of freeze-thawed cycles (p<0.001), while the thickness of endomysium and perimysium were increased (p<0.001). Conclusion: Repeated freeze-thawed cycles degraded muscle fiber structure and deteriorated pork quality.

• Clinical and Experimental Reproductive Medicine
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• 제30권3호
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• pp.193-202
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• 2003

Objective: To evaluate the difference of implantation rate (IR) and clinical pregnancy rate (CPR) between two protocols of endometrial preperation in women undergoing frozen-thawed embryo transfer (FET) cycles. Methods: This study was performed during the different time periods: A retrospective study from January 2000 to June 2001 (phase I) and a prospective study from July 2001 to March 2002 (phase II). All the patients received estradiol valerate (6 mg p.o. daily) starting from day 1 or 2 of the menstrual cycle without pituitary down regulation. Progesterone was administered around day 14 after sonographic confirmation of endometrial thickness $\geq$7 mm and no growing follicle. In Group A (n=88, 99 cycles) of phase I, progesterone was administered i.m. at a dose of 50 mg daily from one day prior to thawing of pronuclear (PN) stage frozen embryo or three days prior to thawing of 6-8 cell stage frozen embryo and then each stage embryos were trasnsferred 2 days or 1 day later after thawing. In Group B (n=246, 299 cycles) of phase I, patients recieved progesterone 100 mg i.m. from one day earlier than group A; two days prior to PN embryo thawing, four days prior to of 6-8 cell embryo thawing. During the phase II, to exclude any differences in embryo transfer procedures, in Group 1 (n=23, 28 cycles) of phase II embryo was transfered by one who have used the progesterone protocol since the phase I. In Group 2 (n=122, 139 cycles) of phase II embryo was transfered by one who use the progesterone protocol from the phase II. Results: When compared across the phase and group, there were no significant differences in the characteristics. During the phase I, there were significant increase in IR (14.4% vs 5.9%, p=0.001) and CPR (28.3% vs 14.5%, p=0.000) in group A. During the phases II, IR (11.8% vs 10.6%) and CPR (27.6% vs 27.3%) show no differences between two groups. Conclusions: In FET cycles, IR and CPR are increased significantly by the change of dosage and timing of progesterone administraton. And the timing is considered to be more important factor because the dosage of progesterone did not affect implantation window in previous studies. Therefore, we suggest that progesterone administration in FET cycle should begin from one day prior to PN stage embryo thawing and three days prior to 6-8 cell stage embryo thawing.

• Journal of Microbiology
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• 제45권6호
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• pp.593-596
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• 2007

In this study, we describe the development of a simple and efficient method for cell lysis via the insertion of a bacteriophage lambda lysis gene cluster into the pET22b expression vector in the following order; the T7 promoter, a gene for a target protein intended for production, Sam7 and R. This insertion of R and Sam7 into pET22b exerted no detrimental effects on cellular growth or the production of a target protein. The induction of the T7 promoter did not in itself result in the autolysis of cells in culture but the harvested cells were readily broken by freezing and thawing. We compared the efficiency of the cell lysis technique by freezing and thawing to that observed with sonication, and determined that both methods completely disintegrated the cells and released proteins into the solution. With our modification of pET22b, the lysis of cells became quite simple, efficient, and reliable. This strategy may prove useful for a broad variety of applications, particularly in experiments requiring extensive cell breakage, including library screening and culture condition exploration, in addition to protein purification.

• International Journal of Highway Engineering
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• 제15권3호
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• pp.53-63
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• 2013

PURPOSES : This study is to evaluate moisture susceptibility of asphalt mixtures by using non-destructive impact wave and to determine durability so as to decrease the gap between before and after freezing in the future. METHODS : Using non-destructive impact wave, this study is to determine the dynamic modulus of asphalt specimen. Furthermore, the results obtained from two experiment accelerometers are used for the dynamic modulus determination. The dynamic moduli of specimens are compared with those of the freezing-thawing specimens. RESULTS : Test results showed that the dynamic modulus before freezing and thawing environment loads at each temperature dropped about 3.7% after the environmental loads. Furthermore, correlation analysis indicates that transition of dynamic modulus at each point is about 89.59%. CONCLUSIONS: Evaluation of asphalt mixtures using non-destructive impact wave has excellent repeatability and simple equipment for the test. Consequently, the method in the study will be useful for evaluating the characteristics of a various asphalt mixtures.

• International Journal of Highway Engineering
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• 제20권3호
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• pp.11-18
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• 2018

PURPOSES : Durability of concrete is traditionally based on evaluating the effect of a single deterioration mechanism such as freezing & thawing action, chloride attack, carbonation and chemical attack. In reality, however, concrete structures are subjected to varying environmental exposure conditions which often results in multi-deterioration mechanism occurring. This study presents the experimental results on the durability of concrete incorporating air-cooled slag(AS) and/or water-cooled slag(WS) exposed to multi-deterioration environments of chloride attack and freezing & thawing action. METHODS : In order to evaluate durable performance of concretes exposed to single- and multi-deterioration, relative dynamic modulus of elasticity, mass ratio and compressive strength measurements were performed. RESULTS :It was observed that multi-deterioration severely affected durability of concrete compared with single deterioration irrespective of concrete types. Additionally, the replacement of cement by AS and WS showed a beneficial effect on enhancement of concrete durability. CONCLUSIONS : It is concluded that resistance to single- and/or multi-deterioration of concrete is highly dependent on the types of binder used in the concrete. Showing the a good resistance to multi-deterioration with concrete incorporating AS, it is also concluded that the AS possibly is an option for concrete materials, especially under severe environments.