• 한국동물생명공학회지
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• 제38권2호
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• pp.70-76
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• 2023

Background: Despite considerable technological advancements, polyspermy remains a significant challenge in in vitro fertilization (IVF) procedures in pigs, disrupting normal embryonic development. Here, we aimed to determine whether optimal fertilization conditions reduce the polyspermy incidence in pigs. Methods: In vitro-matured oocytes were co-incubated with sperm according to a modified two-step culture system. Results: In the first experiment, oocytes were briefly co-incubated with sperm, washed in IVF medium, and then moved to fresh IVF medium for 5 or 6 h. Although the 6 h sperm-free cultured group had a higher penetration rate than the 5 h cultured group, the polyspermy rate significantly increased in the 6 h sperm-free cultured group. The gamete co-incubation period was either 20 or 40 min. The 40 min cultured group had a higher rate of blastocyst formation and number of total cells in blastocysts than the 20 min cultured group. In experiment 2, oocytes were inseminated with sperm separated by Pecroll treatment. Percoll treatment increased the rate of oocyte penetration and blastocyst formation compared to the control. In experiment 3, fertilized oocytes were cultured in 25 µL microdroplets (10 gametes/drop) or 500 µL (100 gametes/well) of culture medium in 4-well plates. The large volume of medium significantly reduced the number of dead oocytes and increased the rate of blastocyst formation compared to the small volume. Conclusions: Collectively, these results demonstrate that various fertilization conditions, including modified co-culture period, active sperm separation, and culture medium volume, enhance fertilization efficiency and subsequent embryonic development by decreasing polyspermy occurrence.

• 한국생산제조학회지
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• 제21권3호
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• pp.387-393
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• 2012

It is very difficult to determine suitable cutting conditions in order to obtain accurate cutting profiles because machining errors caused by tool deflection depend upon cutting conditions. In this study the relationship between real cutting profiles (inclined shapes and machining errors) and cutting conditions was modeled in order to fabricate draft angle on micro molds. CCD (Central Composite Design) of DOE (Design Of Experiment) and RSM (Response Surface Method) were applied in order to model the relationship between cutting conditions and machining errors. In order to use CCD the range of radial depth of cut was chosen by $10-90{\mu}m$ and the range of feedrate was chosen by 200-300mm/min, and 9 points of cutting conditions were chosen inside determined ranges. Then, actual cutting processes were carried out as respect to 9 points of cutting conditions, draft angles and real cutting profiles were measured on cutting profiles, each response surface function was determined by conducting response surface analysis and the functions were represented by 3-dimensional graphs, contour lines and $101{\times}101$ matrices. Consequently it is possible to determine suitable cutting conditions in order to obtain arbitrary given draft angles and cutting profiles by using modeling. To validate proposed approach in this study suitable cutting conditions were determined by modeling in order to obtain arbitrary given draft angle and cutting profile, and actual cutting processes were carried out. About 95% of good agreement between predicted and measured values was obtained.

• Geomechanics and Engineering
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• 제16권4호
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• pp.363-373
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• 2018

The evaluation of Thermo-Hydro-Mechanical (THM) coupling behavior is important for the development of underground space for various purposes. For a high-level radioactive waste repository excavated in a deep underground rock mass, the accurate prediction of the complex THM behavior is essential for the long-term safety and stability assessment. In order to develop reliable THM analysis techniques effectively, an international cooperation project, Development of Coupled models and their Validation against Experiments (DECOVALEX), was carried out. In DECOVALEX-2015 Task B2, the in situ THM experiment that was conducted at Horonobe Underground Research Laboratory(URL) by Japan Atomic Energy Agency (JAEA), was modeled by the research teams from the participating countries. In this study, a THM coupling technique that combined TOUGH2 and FLAC3D was developed and applied to the THM analysis for the in situ experiment, in which rock, buffer, backfill, sand, and heater were installed. With the assistance of an artificial neural network, the boundary conditions for the experiment could be adequately implemented in the modeling. The thermal, hydraulic, and mechanical results from the modeling were compared with the measurements from the in situ THM experiment. The predicted buffer temperature from the THM modelling was about $10^{\circ}C$ higher than measurement near by the overpack. At the other locations far from the overpack, modelling predicted slightly lower temperature than measurement. Even though the magnitude of pressure from the modeling was different from the measurements, the general trends of the variation with time were found to be similar.

• 과학교육연구지
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• 제37권1호
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• pp.79-86
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• 2013

이 연구는 중학교 과학과 실험수업 실태 및 교사의 실험수업에 대한 인식을 조사한 것이다. 실험연수에 참여한 중학교 교사 110명을 대상으로 실험수업에 대한 인식을 설문지 방법으로 조사하였다. 중학교 과학교사들은 이론 중심의 강의식 수업을 주로 실시하고, 실험수업은 1학기에 1~3회의 빈도로 진행하는 것으로 조사되었다. 실험활동은 교과서에 제시된 실험활동의 결과를 확인하는 수준에서 진행하는 것으로 조사되었다. 연구대상에 참여한 교사 대부분은 과학수업지도 능력과 실험수업지도 능력을 평균 이상으로 인식하고 있었다. 실험수업의 장점을 '과학에 대한 흥미 및 호기심 유발,' '과학적 탐구능력 신장,' '과학 이해력 향상' 등으로 인식하고 있었다. 그러나 교사의 '업무과다,' '실험실 여건 요인,' '교육 환경 요인' 등은 과학실험을 저해하는 요인이라고 하였다. 과학교사가 실험을 통하여 학생들의 과학적 태도 형성 및 학습 동기를 유발할 수 있도록 과학교사의 업무 경감, 실험 환경 개선 등에 대한 지속적인 관심과 투자가 요구된다.

• 한국작물학회지
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• 제48권2호
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• pp.120-126
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• 2003

Four different rice varieties, Sindongjinbyeo, Dongjin #1, Saegyehwabyeo, and Iksan 467, were transplanted under three different nitrogen levels and two different seedling numbers per hill to obtain basic information on panicle traits under different cultural conditions and to propose the ideal panicle structure in Japonica rice. Sindongjinbyeo and Iksan 467 were characterized by more primary rachis branches (PRBs) per panicle and more grains on PRB than other cultivars. The two varieties also had fewer secondary rachis branches (SRBs) per PRB and fewer grains on SRB per PRB. These characteristics, consequently, resulted in higher ripened grain rate, contrary to that of Dongjin #1 and Saegyehwabyeo. In the correlation coefficient analysis, PRB number per panicle and grain number on PRB per panicle were positively correlated with ripened grain rate, while SRB number per panicle, number of grains on SRB per panicle, SRB number per PRB, number of grains on SRB per PRB and grain number per panicle were negatively correlated with ripened grain rate. Therefore, the number of grains on PRB per panicle, SRB number per PRB and the number of grains on SRB per PRB were the appropriate criteria for determining and achieving higher ripened grain rate in rice. High ripened grain rate over 90% was obtainable with over 12.5 PRBs per panicle and 63 grains on PRB per panicle, and with under 1.7 SRBs per PRB, 5 grains on SRB per PRB, 130 grains per panicle, and 14 panicles per hill. The study recommended that for over 90% high ripened grain rate, the critical limiting factors should be under 2 SRBs per PRB, 6 grains per PRB, and 130 grains per panicle, irrespective of the PRB number per panicle and the number of grains on PRB.

• 한국응용과학기술학회지
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• 제29권1호
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• pp.40-46
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• 2012

In vivo nicotine is associated with Alzheimer's, Parkinson's and lung cancer. Diagnostic assays of these diseases depend on very low analytical detection limits. In this study, a sensitive analytical method was examined using a voltammetric graphite pencil electrode (GPE) and a modified carbon nanotube paste electrode (CNE). The optimum analytical conditions for both electrodes were compared using square wave anodic stripping voltammetry (SW) and cyclic voltammetry (CV) obtaining 400 sec accumulation time and oxidation peak. Under optimum parameters, the stripping working range of GPE was $5.0-40.0{\mu}g/L$, CNE: 0.1-0.8 and $5-50{\mu}g/L$. Quantification limits were $5.0{\mu}g/L$ for GPE and $0.1{\mu}g/L$ for CNE, while detection limits were $0.6{\mu}g/L$ for GPE and $0.07{\mu}g/L$ for CNE. A standard deviation of $10.0{\mu}g/L$ was observed for 0.064 GPE and 0.095 CNE (n = 12) using 400 sec accumulation time. The results obtained can be applied to non.treated urine and ex vivo biological diagnostics.

• 한국작물학회지
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• 제46권5호
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• pp.401-406
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• 2001

The applicability of non-destructive near infrared reflectance spectroscopic (NIRS) method was tested to determine the protein and oil contents of intact soybean [Glycine max (L.) Merr.] seeds. A total of 198 soybean calibration samples and 101 validation samples were used for NIRS equation development and validation, respectively. In the developed non-destructive NIRS equation for analysis of protein and oil contents, the most accurate equation was obtained at 2, 8, 6, 1(2nd derivative, 8 nm gap, 6 points smoothing, and 1 point second smoothing) and 2, 1, 20, 10 math treatment conditions with Standard Normal Variate and Detrend (SNVD) scatter correction method and entire spectrum (400-2500 nm) by using Modified Partial Least Squares (MPLS) regression, respectively. Validation of these non-destructive NIRS equations showed very low bias (protein: 0.060%, oil: -0.017%) and standard error of prediction (SEP, protein: 0.568 %, oil : 0.451 %) as well as high coefficient of determination ($R^2$, protein: 0.927, oil: 0.906). Therefore, these non-destructive NIRS equations can be applicable and reliable for determination of protein and oil content of intact soybean seeds, and non-destructive NIRS method could be used as a mass screening technique for selection of high protein and oil soybean in breeding programs.

• The Plant Pathology Journal
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• 제19권2호
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• pp.92-96
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• 2003

The study was conducted to determine the cultural conditions and the effect of inert fillers for melanization and sporulation abilities of sodium alginate pellets, and the weeding efficacy of the formula in the field. Melanin production of E. nematosporus was affected by striking frequency. Percentage of melanized beads was increased to 80.6% at higher rpm up to 180. The melanized pellets produced more conidia with abundant mucilage than unmelanized pellets. Shaker culture of Epicoccosorus nematosporus with sodium alginate yielded a total of 55 mg per 100 pellets. Percentage of melanized pellets was highest with 81.0% and 83.3% of melanization, when wheat bran and rice polish were amended and produced the conidia with 65.4 and 68.4 mg per 100 pellets, respectively. When 1 L of conidial suspension of 6.0$\times$$10^5$ conidia per ml was applied on 30-day-old plants in a plot, 74.5% of the plants were killed within 20 days, whereas, its melanized sodium alginate pellets killed 57.8% of the plants in the same period. The number of tuber formation of Eleocharis kuroguwai in the untreated control plots was 128.5 per plot, but those of the plots treated with conidial suspension and melanized pellets were 22.1 and 39.7, respectively, at the end of the season. Results of this study showed that melanization of mycelia-mixed sodium alginate are an important sporulation factor in E. namatosporus as a mycoherbicide.

• 한국작물학회지
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• 제48권5호
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• pp.397-401
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• 2003

This experiment was conducted to know the characteristics of kernel growth as affected by various temperature regimes during grain filling using the varieties Hwaseongbyeo, Ilpumbyeo and Chucheongbyeo. The rice plants tested were grown in the natural condition at 1/5000a Wagner pots until flowering. After flowering, the rice plants were moved to controlled temperature conditions in a phytotron. The minimum/maximum daily temperature in the phytotron was controlled by 12/18, 15/21, 18/24, 21/27, and 24/$30^{\circ}C$, respectively. The grain weights were measured every three days after treatment. The mean daily kernel growth rate during active grain filling period showed different responses among varieties under various temperature regimes. The kernel growth rate of Chucheongbyeo was seriously reduced as temperature regimes were decreased. However, that of Ilpumbyeo was not influenced so critically. Ilpumbyeo showed some advantages in grain filling under low temperature regimes compared to Chucheongbyeo. The lag phase in grain filling of Chucheongbyeo was the longest among tested varieties, followed by Hwaseongbyeo under daily mean temperature regime of $15^{\circ}C$. Kernel weight of Ilpumbyeo increased fast in early grain filling phase under low temperature. This characteristic may be favorable for grain filling in temperate zone where the daily mean temperature is drastically dropped during grain filling period. Regression analysis with kernel growth rate and temperature showed the estimated critical low temperature for grain filling among varieties were $9^{\circ}C$, $12^{\circ}C$, $13^{\circ}C$ in Ilpumbyeo, Hwaseongbyeo and Chucheongbyeo, respectively. Under moderate temperature the duration of grain filling of Ilpumbyeo was longer than that of Chucheongbyeo. However, Under low temperature that of Ilpumbyeo was more favorable than Chucheongbyeo.

• 한국작물학회지
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• 제29권2호
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• pp.118-127
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• 1984

한국 수도작의 재배시기 추정식을 유도하기 위하여1962∼1980년의 지역적응시험성적을 이용하여 몇가지 분석을 한 결과틀 요약하면 다음과 같다. 1. 기상, 지리조건 및 재배시기 상호간에는 고도의 상관이 있었고 기상요인 중에서는 최저평균기온이 재배시기에 가장 크게 작용하나 기타요인들도 관여함을알 수 있었다. 지리적 요인 중에서는 위도, 고도 및 경도의 순으로 기상과 경종시기에 관여하였다. 2. 반종부터 적정출수까지의 전생육일수는 Japonica 품종군의 경우가 115일, I/J품종군은 111일 이었고 육묘기간은 각각 44일과 42일 이었다. 3. 위치결정요소인 위도, 경도 및 고도를 이용하여 파종기, 이앙기, 적정출수기 및 안전출수. 한계기 추정식을 유도한 결과 편회귀계수와 중상관계수가 모두 유의성을 보여 재배시기추정식은 합리적인 것으로 판단되었다. 4. 그러나 본 연구분석에 Topology 효과는 고려되지 않아서 특수지역에의 적용은 어려울 것으로 보인다. 또한 특수생태형을 가진 품종이나 특이한 재배법에의 적용은 좀더 검토되어야 할 것으로 생각된다.