PURPOSES : The aim of this study is to review freeze-and-thaw testing apparatuses, develop a freeze-and-thaw testing setup with a test protocol, test the freeze-and-thaw properties of soils collected from different parts of South Korea, and suggest an index for frost susceptibility criteria for soils found in South Korea. METHODS : Based on a literature review, a new freeze-thaw testing setup was developed. In addition, a test protocol was developed for freeze-thaw testing. Soils collected from different parts of South Korea and bedding sand used for block pavements were tested to determine whether the measurements from the newly developed test setup could capture important freeze-thaw characteristics of the soils. Finally, to develop local frost susceptibility criteria, a parameter including both the vertical deformation and thermal conductivity characteristics of the soils was suggested. RESULTS : The results from the laboratory experiments indicate that the newly developed freeze-and-thaw setup captures the required parameters to quantify the responses of soils subjected to cyclic freeze-and-thaw testing. In addition, a vertical deformation of up to 2.437 mm is measured. Moreover, seven soils out of the nine tested soils are classified as having a medium frost susceptibility, whereas the remaining two show low frost susceptibility. The bedding sand experiment also shows that there is a possibility of having a frost susceptible condition based on the moisture content. When submerged, the bedding sand is classified as having a medium frost susceptibility. CONCLUSIONS : The "HEART" freeze-thaw testing setup was able to capture the parameters required for evaluating the frost susceptibility of soils. This setup and testing procedure could be further used to test and prepare criteria for classifying the frost susceptibility of soils found in South Korea.

콩나물과 같은 고섬유질 야채류의 동결건조 후 조직감 개선을 위한 전처리 방법을 연구한 결과 예비 열처리와 하 이드로콜로이드 및 당 용액 침지를 조합, 적용시 건조 후 조직수축이 개선되고 복원력이 향상 되었다. 100oC의 0.5%(w/w) 염화나트륨 용액에서 2분간 예비열처리한 다음 0.5% 알긴산나트륨과 1.0% 슈크로오스을 첨가한 상온의 용액에서 60분 교반 침지시 열수 복원 후 전반맛, 식감, 외관 등의 관능 품질이 100oC 물에서 1분간 예비 열처리 한 시료 보다 1.6점이나 더 우수하여 큰 개선 효과를 나타 내었으며, 기계적 측정치에서는 전처리 콩나물 줄기의 경 도값이 0.27 kgf로 가정 조리식의 0.26 kgf와 거의 근접한 수치를 보였다. 이러한 전처리 공정을 대파, 쑥갓, 고사리 등의 다양한 고섬유질 동결건조 야채류에 적용시 관능품질 및 복원력이 향상될 것으로 기대되므로 산업화에서 적용 가능성이 높다고 할 수 있다.

본 연구에서 생쥐 초기 배아를 이용하여 동결 보존된 배아의 생존율 또는 발달율에 영향을 미치는 요인들의 상관관계를 알아본 결과, 배아의 발달 단계에 따른 동결 - 해동 후 생존율에 있어서는 2세포기 배아가 4~8세포기 배아보다 유의하게 높았으나(p＜0.01), 배 발달율에 있어서는 4~8세포기 배아가 유의하게(p＜0.01), 높아 생존율과 배 발달율과는 상관관계가 없는 것으로 사료된다. 또한, 동결 보호제에 따른 배아의 생존율에 있어서는 2, 4~8세포기 배아 모두 DMSO에서 유의하게 높았으나(p＜0.01), 배 발달율에 있어서는 EG가 DMSO에 비해 더 유의하게 높은 성적을 나타내어(p＜0.01, p＜0.05) 동해로 인한 상해가 적은 것으로 생각되어 2, 4~8세포기 배아에서 EG가 더 효과적인 동결 보호제로 사료되며, 동결 프로그램으로는 완만 동결 - 급속 해동법이 더 우수한 프로그램으로 보인다.

PURPOSES: It is important to consider the long-term performance of concrete pavement, because concrete pavement is more exposed to the various environmental conditions than any other concrete structures. One of the several methods to evaluate the long-term performance of concrete during winter is KS F 2456. Relative dynamic modulus of elasticity shows the resistance to freezing and thawing. METHODS: To measure relative dynamic modulus of elasticity, ultra sonic is generally used. But in this study, to measure the relative dynamic modulus of elasticity, both ultra sonic and shear wave were used and then compared each other. RESULTS: The results from the measurement by ultrasonic wave and shear wave were divided into three types. Type 1 : Specimens are good and relative dynamic modulus of elasticity did not decrease until 300 cycle. Type 2 : The relative dynamic modulus of elasticity decreased from the late cycle.(about 150 cycle later) Type 3 : The relative dynamic modulus of elasticity consistently decreased from the beginning. As a result of ANOVA, there is no difference according to measuring method, in type 2 and 3. But there is a difference according to measuring method, in type 1's relative dynamic modulus of elasticity. CONCLUSIONS: It is proved that shear wave can be used to understand the damage tendency of relative freezing and thawing and to measure the relative dynamic modulus of elasticity.

For reconstituting genetic resource(Korean Native Chicken: KNC) with grem-line chimeric chicken made with cryopreserved biastdermal cells, the experiments were carried out to optimize cryopreservating conditions. Stage X biastdemal cells were collected from KNC embryos and dissociated. Cells were susupended in medium containing cyopretectant and fetal bovine serum(FBS), and distributed into plastic ampules. Cell susupensions were seeded to induce ice formation at —7 ℃ to —35 ℃ at in the experiments, the effect of modification of dissociation way, concentration of FBS and cell density on the vaibility of frezen-thawed cells were investigated by trypan blue exclusion. Then change the way of cell dissociation from pipetting to short time vortexing, viability of frozen-thawed cell tended to be increaced from 29 % to 52 %. Increase concentraition of FBS in frozen medium from 20 % to 80 % made viability of thawed cell from 28 % to 35 %. The viability of thawed cells were 33.9% frozen at 2 embryos/ 0.5ml, and 43.6 % frozen at 20 embryos/0.5 ml. Furthermore, combination of three modifications make big improvement. The viability of frozen-thawed cell was 60 % for combinated method, and 41 % for general method. This result means the advance to practical cryoreservation of blastdermal cell of the KNC(Ogolgye breed).

The objective of this study was to investigate the effectiveness of cryopreservation methods for the effect of various vitrification containers, such as EM-grid, OPS, or cryo-loop on the survival and developmental rate of vitrified mouse pronuclear embryos, and mouse cleavage embryo, at 21, 24, 27 and 30 hr after hCG injection. Post-thaw cleavage was similar among treatments, while the developmental rates of mouse blastocyst and hatched blastocyst were higher ( <0.05) in 27 hr and 30 hr than 21 hr. The developmental rate of hatched blastocyst at vitrified cleavage mouse embryos in cryo-loop was significantly higher than vitrified pronuclear embryos of control group as well as EM-grid and OPS ( <0.05). The developmental rate using cryo-loop was higher than EM-grid, but in case of OPS at vitrified cleavage and mouse pronuclear embryos, no significant difference was noticed. These results of our study show that the developmental rates of mouse embryos were unaffected by various vitrification containers, but in case of mouse embryos and hatched blastocysts at late vitrified pronuclear embryos the developmental rates were higher than early vitrified pronuclear embryos. Moreover, the developmental rate of hatched blastocyst at vitrified cleavage mouse embryos was significantly higher than vitrified pronuclear embryos. For better execution of this study, it will be mandatory to include improvement of vitrification containers, cryopreservation methods and conditions, higher survival rate, safe preservation, contamination and embryo loss.

The objective of this study was to examine the effect of various discontinuous Percoll washing conditions on motile sperm recovery rate and motion kinematics. Frozen semen samples from 3 bulls (0.5 ml plastic straws, 6% glycerol in egg yolk-Tris-glycerol extender) were thawed in 37℃ water bath for 1 min. After thawing, the mixed semen samples were randomly allocated to 12 treatment groups. Briefly, the spermatozoa were centrifuged for three different time lengths (10, 20, and 30 min) at two gravities (300×g and 700×g) through two concentrations of discontinuous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll and 2 ml 90%: 2 ml 45% Percoll to remove extender, debris, and dead spermatozoa. Motile sperm recovery rate and motion kinematics were evaluated by computer assisted sperm analyzer using Makler counting chamber. Sperm motility (%) and motile sperm recovery rate showed similar pattern in all treatment groups. However, sperm motility (%) and motile sperm recovery rate were highest at 700×g for 30 min through a discontionous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll. There were no significant differences in motion kinematics after various Percoll washings. These results suggest that force of centrifugation, centrifugation time, and Percoll volume significantly affect motile sperm recovery rate.

The objective of this study was carried out to evaluate the efficiency of sperm collection methods on the post-thaw viability of cat semen. The cat semen was collected by artificial virginal (AV) and electronic ejaculate (EE) methods. The composition of semen extender was consisted of Tris-buffer supplemented with 20% egg yolk and 1% P/S antibiotics in Ext I, and more added 8% glycerol, 1.0% Equex STM paste of total volume in Ext II. The collected semen was adjusted the concentration and then diluted in Ext I for optimal concentration. The diluted semen was cooling to 5℃ temperature in refrigerator for at least 2 hrs and then diluted stepwise with Ext II for at least 1 hrs. After an equilibration for 1 hrs, the cooled semen was packaged in 0.5 ml straw and then freezing on the LN2 vapor over 5 cm above from LN2 and then immersed directly in LN2 for cryopreservation. The frozen semen was thawed in 38℃ water for 15 sec and then evaluated the motility, viability, and morphology. Post-thaw semen were calculated the motility by SMI (sperm motility index). The live-dead sperm was evaluated by Eosin-B and morphological evaluation was by Diff-quik kit staining. The post-thaw concentration (89×106 /ml vs. 128×106 /ml), viability (22.6±10.6% vs. 37.1±26.1%), morphological normality (27.0±50.2% vs. 45.6±123.0%) of EE and AV groups were not significant different, but the post-thaw motility was significant lower in EE than that in AV group (53.1±3.6 vs. 73.6±5.7) (p<0.05). In conclusion, semen collection methods did not significant different between EE and AV groups except of post-thaw motility and so both semen collection methods could be applied in feline semen collection methods.

In previous studies, we reported that sow which was transferred OPS-freezing embryos not able to deliver a piglet (Kim et al, 2004). This study was conducted to investigate a possibility of gilt as recipients which produce piglets after transfer of OPS-freezing embryos. All transferred embryos were prepared by in vitro production (IVP) system. In vitro culture (IVC) medium used glucose-free NCSU23 supplemented with 5mM sodium pyruvate, 0.5 mM sodium lactate and 4 mg/ml bovine serum albumin for 2 days at . From day 3 of IVC, 10% fetal bovine serum albumin was added to the culture medium. In preparing of freezing embryos, embryos were treated with 7.5 cytochalasin-B for 30 min and centrifuged at for 13 min. And then, embryos were exposed sequentially to an ethylene glycol (EG) solution, aspirated into open pulled straw (OPS), and plunged or thawed into the liquid nitrogen. In embryo transfer (ET), we used two kinds of type (surgical method vs. non-surgical method). In surgical method of embryo transfer, embryo were transferred in both uterine horn of two recipient gilts by plastic straw. Non-surgical method which is like artificial insemination was performed on three gilts. Each 140 frozen embryos were transferred to two gilts and 40 fresh embryos to one gilt. Pregnancy establishment was shown one recipient at 45 days after ET. However, the one recipient was also aborted at 58 days after ET. These results suggest that gilts can be considered as a candidate of recipients for OPS-freezing embryo transfer.

본 연구는 Open Pulled Straw(OPS)방법에 의해 동결-융해한 돼지 수정란의 체외 생존 능력을 검토하기 위하여 수행되었다. 미성숙 난자의 체외 성숙을 위하여, 돼지 난소는 도축장에서 회수하였으며, 난구세포로 쌓여있는 난자는 직경 의 난포로부터 난포액과 함께 흡입에 의하여 회수하였다. 회수된 미성숙 난자의 체외 성숙을 위하여 5 mM hypotaurine, 0.57 mM cysteine, 10% 난포액, 10 IU/ml PMSG 및 10 IU

본 연구는 마우스의 성숙 난자와 수정란의 유리화 동결을 위한 CPS, 기존 straw 및 OPS 방법의 효과에 대하여 비교하였다. 마우스 난자의 유리화 동결-응해 후 형태학적인 생존율을 조사한 결과, CPS (75%)와 기존 straw(72%)법이 OPS(68%)법에 비해 유의적으로 높은 생존율을 나타내었다(p<0.05). 과배란 처리 후 채란한 2-세포기 마우스 수정란을 유리화 동결-응해하여 일간 배양한 다음 수정란의 배 발달 상태를 비교한 결과, 동

본 연구는 돼지정액의 보다 간편하고 손쉽게 동결시킬 수 있은 방법을 확립하기 위하여 수행하였다. 돼지정액은 3시간에 걸쳐 5℃까지 냉각 후 Straw에 봉입하고 다양한 방법 및 step에 의해 스티로폼 용기 내에 들어있는 LN2 중에서 동결하였다. 정자의 생존성은 LN2 표면으로부터 10 cm 위에서 10분간 정치 후 침적할 경우 가장 높게 나타났다(54.0%). Straw를 -102℃에서 10분간 정치시킨 처리구가 여타구보다 높은 생존성이 얻어졌다(74.0%, P<0.05). 응해 방법에 따른 동결정액의 생존성 실험에서는 37℃의 융해구가 52℃ 융해구보다 유의적으로 높은 결과를 나타냈다(P<0.05). 1단계 동결 방법과 3단계 동결방법으로 돼지 정액을 동결시킨 결과 정액의 일반적 특성 및 첨체의 이상 유무를 평가하는 CTC 검사에서는 커다란 차이가 인정되지 않았다. 동결정액을 이용한 체외수정 결과에서는 상실배기 이상 발육율에서 1-step이 3-step보다 높은 발육율을 나타내었다(27.5 vs 14.7%, P<0.05). 본 실험의 결과 돼지정액 동결 시 -102℃에서 10분간 정치시키는 1단계 동결방법이 간편하면서 유리한 동결 방법으로 활용될 수 있음을 보여준다.

본 연구는 OPS 기법에 의한 돼지 수정란의 동결-융해 시 수정란의 발달 단계와 superoxide dismutase (SOD)가 수정란의 생존능력에 미치는 영향을 검토하였다. 돼지 체외수정 배반포는 OPS방법에 의해 동결 후 융해하여 0~10unitsml의 SOD 존재 하에 48시간 체외배양하였다. 동결-융해 후 형태학적으로 정상적인 수정란의 비율은 초기, 중기 및 확장배반포간에 유의적인 차이는 인정되지 않았다(30.8~38.6%). 그러나 발육단계가 높을수록 형태적으로 정상인 수정란의 비율이 높은 경향을 나타냈다. 수정란의 융해 후 48시간 추가 배양했을 때, 발육이 진행된 수정란은 후기배반포기에 동결한 수정란이 38.7%로 유의적으로 높았으며(P<0.05), 1 unit/ml의 SOD를 첨가한 경우 비교적 높은 생존율을 나타내었다. 본 연구의 결과로부터, 수정란의 OPS방법에 의한 동결-융해 후 생존성의 향상을 위해서는 후기배반포기 단계에 동결하는 것이 유리하며, SOD의 첨가는 수정란의 손상을 어느 정도 방지할 수 있을 것으로 사료된다.