• Applied Biological Chemistry
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• v.46 no.1
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• pp.39-45
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• 2003

This study was conducted to investigate the effect of ash contents of bread flour on the rheology of frozen dough In making frozen dough by measuring amylograph, flrinograph and extensograph. The quality of frozen-stored dough under freezing condition ($-20^{\circ}C$, 12 weeks) was evaluated by measuring final proof time, moisture content, baking loss, loaf volume and hardness of bread with storage time. In bread flour with high ash content farinogram showed that water absorption, degree of softening increased but valorimeter value decreased. In bread flour with low ash content amylogram showed that gelatinization temperature and maximum viscosity increased and extensogram showed that the area and resistance of the bread flour increased. As the proof time increased the extensibility decreased. Final proof time of frozen dough was shortened at the bread flour with low ash content with storage time. In bread using the flour with high ash content, moisture content, increased but baking loss rate decreased while the hardness of product increased slowly with time. But in bread using the flour with low ash content, the loaf volume of baking increased but the hardness of product decreased. As the frozen storage time was shortened, the product was more stable and better in quality.

• International Journal of Highway Engineering
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• v.20 no.3
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• pp.1-9
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• 2018

PURPOSES : In order to evaluate a crack resistance at cold joint, sealing tape was adopted to apply at cold joint instead of typical tack coat material(RSC-4). The sealing tape was made by hot sealing material. The crack resistance as function of environmental and traffic loading was measured with visual observation. METHODS : In this study, the crack resistance was evaluated as function of environmental and traffic loading. The freeze-thaw method was adopted for environmental loading of asphalt pavement. condition. The damage of cold joint under freeze-thaw action is initiated by ice expansion load and accelerated by the interfacial damage between new and old asphalt pavement. The traffic loading was applied with wheel tracking machine on the cold joint area of the asphalt pavement for 3 hours at $25^{\circ}C$. The evaluation of crack resistance was measured with visual observation. The freeze-thaw results shows that the sealing tape was significantly increased the crack resistance based on. RESULTS : To estimate the crack resistance at cold joint area due to the environmental loading, the Freeze-thaw test was conducted by exposing the product to freezing temperature(approximately $-18^{\circ}C$) for 24 hours, and then allowing it to thaw at $60^{\circ}C$ for 24 hours. The tack coat material(RSC-4) was debonded after 21 cycles of the Freeze-thaw test. The first crack was observed after 14 freeze-thaw cycle with RSC-4 material. But, the sealing tape was not debonded after 24 cycle test. Also, the sealing tape shows the better performance of the crack resistance under the traffic loading with wheel track test. The crack was generated the under traffic loading with RSC-4(tack coating), however, the crack was not shown with sealing tape. It indicates that the sealing tape has a strong resistance of tensile stress due to traffic loading. CONCLUSIONS :Based on limited laboratory test result, a performance of crack resistance using the sealing tape is better than that of general tack coat material(RSC-4). It means that the sealing tape is possible to extend a pavement service life because the crack, one of the main pavement distresses, will be delayed.

• Culinary science and hospitality research
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• v.20 no.6
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• pp.211-222
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• 2014

This study was performed to identify the quality characteristic of Platycodon grandiflorum for blanching(1, 2, 3 min), drying(5, 10, 15 min) conditions and thawing methods($4^{\circ}C$, $25^{\circ}C$, running water). The color, moisture contents, pH, hardness, viable cell count of blanched Platycodon grandiflorum were lower than those of native Platycodon grandiflorum. The sensory properties of blanched Platycodon grandiflorum for blanching and drying time showed the most highly evaluated in terms of texture. The optimum blanching and drying times selected for producing of frozen Platycodon grandiflorum were 1 min, 5 min. At this condition, the blanched Platycodon grandiflorum was frozen at $-40^{\circ}C$. After thawing of frozen Platycodon grandiflorum, the thawing time was the shortest in the case of thawing in running water, and drip loss was the lowest. The color, hardness and sensory properties did not significantly differ with different thawing methods. These results show that thawing in running water is the most suitable for frozen Platycodon grandiflorum.

• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.206-214
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• 2001

Water quality and Pollution state of Lake Chungcho were evaluated during three years from 1998 to 2000. We surveyed physicochemical parameters, and TSI (trophic state index) was calculated using TP, Chl. a, and SD (secchi disc transparency) data of growing season average. Water samples were collected bimonthly except freezing season. During the study period, total annual precipitation in 1998, 1999 and 2000 year was 1,797,1,722 and 1,345 mm, respectively. Salinity and conductivity were high($29.3{\pm}5.5\;ppt$, and $45,105{\pm}7,585\;{\mu}S/cm$) then other lagoons in the Eastern Coast of Korea. Chemocline was formed by salinity at $0.5{\sim}1.5\;m$ water depth. As a result of this, DO concentration of hypolimnion was below $3.0\;mgO_2/L$. Especially, when intense chemocline was formed, temperature of hypolimnion was higher than epilimnion. Secchi disc transparency, chlorophyll a, and COD were $1.8{\pm}0.3\;m$, $15.7{\pm}20.7\;mg/m^3$, and $3.1{\pm}0.8\;mgO_2/L$, respectively. Most of TN/TP ratios below 20, but concentration of TN and TP was high. Values of TSI ranged between 59 and 77, indicating a eutrophic condition in this system.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.21-26
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• 2007

본 연구는 mSOF(modified synthetic oviduct fluid medium) 배양액을 이용하여 $100{\mu}1$와 $10{\mu}1$ 배양 소적에서 일본 흑우의 수정란 생산 효율을 개선하기 위하여 수행하였다. 난구세포가 부착된 미성숙 난자는 각각 단독 배양조건($S;\;10{\mu}1$ 소적) 및 그룹 배양 조건 ($G;\;100{\mu}1$ 소적)에서 실시하였고 배양액은 TCM-199의 기본 배지에 10% FCS, 0.02IU/ml FSH와 $1{\mu}g/ml$ $estradiol-17{\beta}$를 첨가하여 사용하였다. 배반포 단계로 발육한 수정란은 1.5M ethylene glycol로 직접 이식법에 의한 동결 방법으로 동결을 실시하였고, 세포수는 융해 후 생존 수정란에 대해 조사하였다. 체외 배양 시간이 $16{\sim}17$시간 배양 조건에서 난자의 성숙율은 그룹 배양 조건$(27.1{\pm}16.8%)$보다는 단독 배양조건$(57.1{\pm}15.0%)$에서 성숙율이 높았다(p<0.05). 그러나 체외 배양 시간이 $18{\sim}19$ 시간과 $20{\sim}21$시간 배양시는 유사한 성숙율을 보였다. 난자의 체외 배양율은 체외 배양 시간의 증가에 의해 성숙도가 $86.3{\pm}9.9%$로 증가하였다. 접합체(zygote)의 분할율은 단독이나 그룹 배양 조건에서도 유사한 결과를 얻었다. 배반포 발달율은 배양 $7{\sim}8$일째에 조사한 결과 단독 배양 방법보다는 그룹 배양 방법에서 발달율이 높았으나, 분할된 접합체를 기준으로 한 경우 배반포 발달율$(S;\; 21.4{\pm}10.6%,\;G;\;39.0{\pm}13.1%)$에서는 유의적인 차이가 없었다. 단독 배양과 그룹 배양에서 $6.5{\pm}8$일 사이에 배반포로 발달된 수정란의 세포수 조사에서는 유사한 결과를 얻었다. 동결 융해 후 24시간 배양 후 배반포 생존율(5; 24.2%, G; 30.2%), 부화율(S: 20.9%, G: 12.7%) 및 생존 수정란수(S; 45.2%, G: 42.8%)에서도 배양 조건에 따른 유의적인 차는 없었다. 결론적으로 mSOF배양액을 이용하는 경우 미성숙 난자의 체외 성숙 유도 배양 시 단독이나 그룹 배양 시 배반포 발달율에서 그룹간에 유의적인 차가 인정되었다(p<0.01).

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.249-264
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• 1995

Although liposome has many advantages as a pharmaceutical dosage form, its application in the industrial field has been limited because of some problems such as preparation method, reproducibility, scale-up, stability and sterilization etc. Liposomes prepared by microemulsification method had defined size, narrow size distribution, reproducibility and high entrapment efficiency. For enhancing the stability, the dry form of liposome was recommended. These types of liposome are proliposome and freeze-dried liposome. The liposome must have some properties for preparing of freeze-dried liposome; small size $(50{\sim}200\;nm)$, narrow size distribution and cryoprotectant. In this experiment, the liposomes containing 5-Fluorouracil(5-FU) and its prodrug(pentyl-5-FU-1-acetate; PFA, hexyl-5-FU-1-acetate; HFA) were made with soybean phosphatidylcholine, cholesterol, stearylamine(SA) and dicetyl phosphate(DCP) employing hydration method or microemulsification method using $Microfluidizer^{TM}$. Both or liposome types were MLV and MEL. After preparation, freeze drying and rehydration were performed. In the process of freezing, trehalose(Tr) was added as a cryoprotectant. Their evaluation methods were as follows; entrapment efficiency, mean particle size and size distribution, dissolution test, retain of entrapment efficiency and turbidity after freeze-drying. The results are summarized as belows. The entrapment efficiency of 5-FU was dependent on total lipid concentration and cholesterol content but that of PFA and HFA was decreased when cholesterol was added. When DCP and SA were added, entrapment efficiency was decreased. As the partition coefficient of drug was increased, entrapment efficiency was increased. Under the same condition, entrapment efficiency of MEL is similar to that of MLV. The mean particle size and size distribution of MEL were smaller than those of MLV. Dissolution rates of drug from both liposome types were comparatively similar. Dissolution rates of drugs with serum and liver homogenate were faster than without these material. After preparation of liposome, free drug was removed efficiency by Dowex 50W-X4. When liposome was freeze-dried and then rehydrated in the presence of Tr, characteristics of liposome were maintained well in MEL than MLV. Tr Was used successfully as a cryoprotectant in the process of freeze drying and the optimal ratio of Tr:Lipid was 4:1(g/g).

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.1-17
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• 1991

It is widely recognized that the embryonic or fetal loss after breeding is common in the cattle and that it is an important factor affecting reproductive efficiency. The causes of this loss have been subject of extensive researches and the results indicate that the embryonic mortality may he primary factor responsible for low pregnancy rates in non-embryo transfer bovine populations as well as embryo transfer programs. However, it's causes are still not clearly understood. The embryonic mortality or pregnancy rate has been influenced by various embryonic and maternal effects related to genetic and environmental factors. The timing and extent of embryonic mortality vanes greatly according to authors and estimating methods, because it is difficult to make direct measurements. The major important factors that may influence the embryonic losses or pregnancy rates after embryo transfer can be summeirized. 1.When an embryo is transferred to unmated recipients, the contralateral transfer to corpus luteum results in a lower survival rate than ipsilateral deposition. When the embryos are transferred for the production of twin calves, their survivals and twin pregnancies have quite inconsistent according to the transfer methods either to the unmated-synchronized or already mated recipients and more works are needed to accurrately clarify the previous results. 2.Although embryos can be cultured in vitro some hours without the great declines in pregnancy rates, the rates differ markedly among culture times and media but may be improved by co-transfer systems. 3.Embryo developmental stages and quality grades clearly affect the survival rate following freezing and the pregnancy rate after transfer and the selection of embryos without chromosome abnormalities and of high fertile semen may also be considered to increase the pregnancy rates. 4.Many researches have attempted to relate the plasma progesterone levels to pregnancy rates and others have done either direct progesterone supplementation or luteal stimulation by hCG treatment in order to increase the pregnancy rates. However, these effects on pregnancy rates are inconsistent and also contradictory. 5.The asynchrony between donors or embryos and recipients may he a major cause of embryo death and low pregnancy rate and the sensitivity to uterine asynchyony differs in according to the quality and stages of embryos. 6.The extremes of poor or over nutrition during early pregnancy in the recipients are detrimental to the survival of embryos and the good body condition is required to prevent a reduejion of pregnancy rates. The uterine pathogens in embryonic mortality or fertility have been questioned but the infection of C.pyogenes and Campylobacter fetus is still important pathogens. 7.The heat stress during early pregnancy may reduce conceptus weight and possibly increase the embryonic mortality.

• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.299-309
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• 2000

This study was performed 1) to establish the optimal PCR condition of sex determination in Hanwoo IVM/IVF embryos, 2) to examine the sex determination and sex ratio to the developmental stages of Hanwoo IVM/IVF embryos by two-step PCR method. The sexing of bovine IVF embryos were accurately determined by PCR methods using Y chromosome specific DNA primer(BOV 97M, 141bp) and bovine specific DNA primer(216bp). The fregment size were shown at 141 and 216 base pairs(bp) in male, and 216 bp in female. Two-steps PCR method in which the samples were amplified by 15 cycles with Y chromosome specific DNA primer and then amplified by additional 30 cycles with bovine specific DNA primer was effective in the sexing of bovine IVF embryos. The zona-free embryos were more effective than zona-intact embryos in bovine IVF embryo sexing. The appearance of Y chromosome specific band was 45.2% in embryos treated with protease K and 53.3% in embryos treated with freezing and thawing repeatedly. The optimun volume of DNA for sexing of Hanwoo IVF embryos were 2 to 10 $\mu$1 in Zona-free embryos and 12 to 13 $\mu$1 in zona-intact embryos. The sexing rate of bovine IVF embryos by PCR was 96.0% and questionable rate not identified sex was 4.0%, respectively. Among the sexed embryos, the percentage of male and female was 49.7% and 46.3%, respectively, the sex ratio was 1: 1.1. The successful rate of embryo sexing was increased to the developmental stages.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.588-596
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• 1996

The optimum conditions of the 1st and 2nd distillation had been investigated to obtaine a high quality monomeric MDI and fire reactive polymeric MDI by purification of crude MDI. Effect of additives on the monomeric MDI's color change, dimerization and the reactivity of polymeric MDI with standard polyol system has been tested. When the monomeric MDI yield is approximately 32%, 4,4'-MDI content is above 98% in the monomeric MDI at the 1st distillation. When the separation ratio of initial portion and residue percentage, reflux ratio are set at respectively, approximately 20wt%, 9wt%, above 2 in order to minimize the content of 2,4'-MDI in monomeric MDI, the freezing point of final distilled monomeric MDI is above $38.4^{\circ}C$. Since the monomeric MDI is inherently unstable in the room condition, monomeric MDI easily changes it's color and conducts self-polymerization reaction. To increase the stability of monomeric MDI, the composition of antioxidant, which is composed of phenolic 1st antioxidant, phosphorus 2nd antioxidant, UV absorbent and Hindered amine light stabilizer are used, and benzoyl chloride as antipolymerization agent test are that APHA color is less than 20, dimer content is remained less than 0.36wt% after 45 days storage of monomeric MDI.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.413-420
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• 1997

In this study, germination characteristics and effect of some chemicals on germination of Trapa japonica $F_{EROV}$ seeds were investigated to obtain a fundamental data for controlling them. When the seeds were stored at low temperature for at least 3 months, their dormancy was completely released with a germinability of above 90%. However, those stored under the room or high temperature condition were never germinated. Germination was best at constant temperature of around $25^{\circ}C$ or at alternate temperature of 25/$15^{\circ}C$ (12 hr-day/12 hr-night), and was nat dependent on light. They could germinate though planted at the depth of 15 cm, but their initial growth were: suppressed with increase of planting depth, especially above 10 cm depth. Germinability was lost when the fresh weight was decreased more than 30%, indicating that the seed is sensitive to dehydration. The freezing at $-20^{\circ}C$ for 1 hr didn't affect germination, but 5 hr treatment completely killed them. Their germination was inhibited by 100% at 100 ppm ABA and slightly inhibited above 25 ppm of butachlor, whereas pyrazosulfuron-ethylnt is likely to control T. japonica physically and herbicide treatment to inhibit germination may not be recommendatory. and bensulfuron-methyl didn't inhibit the germination at the concentration of 100 ppm. Taken together, dehydration treatme is likely to control T. japonica physically and herbicide treatment to inhibit germination may not be recommendatory.