• Korean Journal of Dental Materials
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• v.45 no.4
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• pp.275-286
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• 2018

The purpose of this study was to evaluate the effect of needle tip design and position, and irrigant flow rate on apical pressure (AP) during root canal irrigation. Five human mandibular premolars were instrumented up to #35 (0.06 taper) using nickel-titanium rotary instruments. Three different needles according to change of needle tip design (notched, side-vented, and flat) were positioned at the point of 1, 3, and 5 mm from the apical constriction (needle tip position). For each needle tip design and position, APs were measured with varying flow rates of 0.05, 0.1, 0.2, and 0.3 ml/s. When the other conditions were controlled, AP increased with decreasing needle tip position or increasing irrigant flow rate (p<0.05). The AP of flat needle was the highest, followed by notched, side-vented needle for the same needle tip position and irrigant flow rate. The APs at needle tip position of 1 mm or with more than 0.1 ml/s flow rate were higher than central venous pressure (5.88 mmHg) for all conditions. Flat needle was not recommended for clinical use due to sharp increase of AP with changing needle tip position and irrigant flow rate. For safe and effective root canal irrigation, irrigant should be applied with the needle tip position of 3 mm and flow rate of less than 0.05 ml/s.

• The Korean Journal of Community Living Science
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• v.15 no.4
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• pp.61-66
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• 2004

To develop natural food preservatives with Maesil (prunus mume), investigation of antimicrobial activities against food-related bacteria and yeast was conducted. Maesil (prunu mume) extract exhibited growth-inhibiting activities for most of the microorganisms tested. Minimum inhibitory concentrations (MIC) of maesil extract for Staphylococcus aureus and Bacillus subtilis were as low as 0.1mg/ml. The antimicrobial activity of the maesil (prunu mume) extract was reduced by heating or alkali treatment. Moreover, growth of Staphylococcus aureus was completely inhibited within 24 hours by the addition of at least 100 ppm of maesil extract. These findings suggest that maesil extract may play a role in the development of natural food preservatives.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.137-137
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• 2003

• Proceedings of the Korean Society of Veterinary Service Conference
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• 1999.05a
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• pp.177-177
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• 1999

• 대한생식의학회:학술대회논문집
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• 1997.11a
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• pp.52-52
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• 1997

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.137-137
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• 2003

난자의 체외성숙 및 체외배양에는 일반적으로 동물의 혈청을 기본배양액에 5-10% 정도 첨가한 배양액을 사용하고 있다. 그러나, 혈청으로부터 바이러스, 세균, 마이코 플라즈마 등에 오염될 가능성이 있기 때문에, 본 실험에서는 완전 무혈청 배양액에서 난자의 성숙, 배발생, 세포수, 동결성을 검토하였다. 도축된 한우의 난소로부터 채취한 난자는 선별하여 TCM199+10% FBS와 IVMD 101 배양액에서 22~24시간 동안 체외성숙시킨 후, IVF 100(일본, 펩티트연구소)으로 2회 세정한 후, 각각의 배양액 50${\mu}\ell$ 소적에 5개씩 5~6 시간 수정시켰다. 체외수정한 수정란은 TCM 199+10% FBS, IVMD 101, IVD 101 배양액에서 7~8일간 배양하여 배발생율을 조사하였다. 발생된 배반포의 일부는 세포수를 조사하였고 나머지 배반포는 1.8M EG로 동결하였다. (중략)

• Korean Journal of Animal Reproduction
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• v.15 no.1
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• pp.49-57
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• 1991

This study was carried out to investigate the effect of equilibration time, precooling and straw loading method on the post-thaw survival rates of mouse embryos cryopreserved by vitrification method. The effect of the vitrification procedure on the damage of the embryos was also examined by the straining of nuclei using Hoechst 33342. The results obtained were summarized as follows; 1. The equilibration in Medium-1 for 10 minutes was considered to be the optimum equilibration time. Embryos equilibrated in Medium-1 for 10 minutes(81.0%) showed significantly(P<0.05) higher survival rates than those equilibrated for 5 minutes(40.0%) or 15 minutes(74.1%). 2. The survival rate of embryos cryopreserved using the double Medium-2 column(81.0%) was significantly(P<0.01) higher than that using the single Medium-2 column, whish was considered to be due to the double Medium-2 column method being more reliable for preventing contamination of diluent solution of 1M sucrose. 3. The survival rate of compacted morula stage embryos cryopreserved with the precooled and non-precooled Medium-2 was not significantly(P<0.05) different. 4. The number of blastomeres of embryos at late blastocyst stage after culture of mouse morulae for 24 to 28hours was significantly(P<0.05) decreased by freezing embryos using vitrification(53.3${\pm}$1.6 vs 41.4${\pm}$1.5), which was considered to be due to the damage of embryos during vitrification and the delay of embryo development by handling in vitro. 5. The vitrification procedure is considered to be a very simple and efficient method for cryopreservation of embryos at early developmental stage.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.149-159
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• 2008

Background: With increasing coronary bypass and peripheral vascular surgeries, the demand for homologous vascular or synthetic conduits has continued to grow, but wide-spread application has been limited by dismal patency rates. Although cryopreserved allograft valves may provide a suitable alternative, current viability or patency of implanted allograft vascular conduits has been unsatisfactory. Material and Method: We serially analyzed the outcomes of canine femoral artery and saphenous vein allograft implants after storage in either $4^{\circ}C\;or\;-170^{\circ}C$. Result: There were no differences in graft flow rate (patency) (p=0.264), rate of thrombosis (p=0.264), presence of endothelium (p=0.587), or immunohistochemical staining for thrombomodulin (p=0.657) were detected between grafts stored in $4^{\circ}C\;and\;-170^{\circ}C$. Greater flow occurred in the arterial grafts versus the venous grafts (p=0.030), irrespective of the preservation method, with a significantly lower incidence of thrombosis (p=0.030) in arterial allografts. There was a correlation coefficient of -0.654 between thrombosis and positive immunohistochemical staining for thrombomodulin (p=0.006) and a correlation coefficient of 0.520 (p=0.0049) between the endothelial presence and positive immunohistochemical staining for thrombomodulin. The relationship between the presence of endothelium and thrombomodulin expression failed to show any correlation within the first 2 weeks (p=0.306). However, a strong correlation was seen after 1 month (p=0.0008). Conclusion: Tissue storage in either $4^{\circ}C\;or\;-170^{\circ}C$ in 10% DMSO/RPMI-1640 preservation solution preserved grafts equally well. In terms of thrombosis and graft patency, arterial grafts were superior to venous grafts. Considering the poor correlation between thrombomodulin expression and the presence of an endothelium in the implanted graft within the first two weeks, grafts in this period would not be thromboresistant.

• Environmental and Resource Economics Review
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• v.15 no.5
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• pp.921-937
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• 2006

In this paper, we apply fuzzy theory in a discrete choice Contingent Valuation Method(CVM) in order for dealing preference uncertainty problem. Fuzzy membership function is used in an empirical analysis to estimate the willingness-to-pay(WTP) for the preservation of the endangered Asiatic Black Bear in Korea. The estimated WTP was about 9,090 Korea Won per household with 78 percent of confidence level. The advantage of applying fuzzy theory in the valuation method could be found in its ability to measure the confidence level of the estimated WTP.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.77-77
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• 2001

본 연구는 돼지 동결정액의 번식성적을 개선코자 기존의 maxi-straw와 cryogenic-vial을 이용하여 포장방법에 따른 동결방법과 융해방법별 정액성상 및 번식성적을 비교하였다. 동결방법은 두 가지 포장방법 모두 정액의 양(5$m\ell$)과 농도(5.0$\times$$10^{9}$/dose)가 동일한 조건으로 처리하였으며, LYE(Lactose egg york extender) 보존액으로 희석하여 액체질소 상단 15cm에서 20분간 동결하였다. 융해방법은 maxi-straw는 52$^{\circ}C$에서 45초간 cryogenic-vial은 52$^{\circ}C$에서 190초간 융해하여 $25^{\circ}C$로 가온 된 80$m\ell$ BTS (Beltsville thawing solution) 보존액과 혼합하였다. 정액성상검사는 정자자동분석기(SAIS : Sperm Analysis Image System, Korea)를 이용하였다. 총활력(TM : Total motility)과 정자의 빠르기(VCL : Curve linear velocity)는 maxi-straw가 54.3%와 46.6%로 cryogenic-vial의 35.6%와 36.6%보다 우수하였다(P<0.05). 정자의 직진성(STR : Straightness)과 NAR은 maxi-straw가 53.2%와 32.6%로 cryogenic-vial의 47.3%와 29.8%와 비슷한 경향을 나타내었다. 수태율과 분만율 및 총산자수는 maxi-straw가 77.3%, 68.2% 및 8.0두로 조사되어 cryogenic-vial포장방법의 66.7%, 61.9% 및 7.4두보다 다소 우수하였으나 통계적인 유의차는 인정되지 않았다. 이상의 결과로 볼 때 cryogenic-vial방법이 새로운 돼지 동결정액 포장방법의 가능성을 나타낸다고 사료된다.