• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.127-134
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• 1996

The objective of this experiment was to test the ability of the fertilization of EGF treated pig oocytes for in vitro maturation. The addition of EGF (10 ng/ml), FSH (10 ${\mu}\textrm{g}$/ml), or FBS (10%) on maturation medium of pig immature oocytes divided into four groups as follows; group 1: untreatment, group 2: EGF alone, group 3: combination of FSH and FBS, or group 4: combination of EGF, FSH, and FBS. The interactive effects of nuclear maturation rates (M II%) of EGF alone, FSH plus FBS, and EGF plus FSH added FBS treatments were significantly higher than those of non-treatments (P<0.001). The fertilization rate of EGF alone (group 2) was lower than that of 3, 4 groups, but was significantly higher than group 1 (p< 0.005). Furthermore, combination of EGF, FSH,and FBS (group 4) was higher than others (group 1. 2, 3) on male pronuclei formation as well as penetration of sperm (P<0.05). These results suggested that EGF alone decreased the ability of cytoplasmic maturation compared to nuclear maturation in pig oocytes, but a high level of cytoplasmic maturation of in vitro-matured pig oocytes can be achieved when supplemented with FSH and FBS.

• Journal of Korean Society of Rural Planning
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• v.5 no.1 s.9
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• pp.95-103
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• 1999

The purpose of this study is to find out the distribution of underground biomass and its soil stabilizing effects. Bamboo and grass were examined and compared. 1. Thirty 'soil & root' samples were collected to the depth of 30cm with Impact-corer, and then divided into three sections(0-10cm, 10-20cm, 20-30cm). Each piece had a volume of $950cm^3$ and the underground biomass was separated from the soil particles by washing with flowing water. The average underground biomass rates of bamboo and grass were 10.8% and 4% of each sample, respectively. The rate of grass root biomass declined with depth, but the bamboo root biomass was at peak at around 20cm depth. 2. The shear strength was measured with con-penetration tester at each sample collecting site. Three measurements were made at each depth(0-10cm, 10-20cm, 20-30cm) and were compared with the impact counts needed to insert the corer to the depth of 30cm. The shear strength has clear correlations with underground biomass. The more underground biomass, the higher shear strength. The shear strength of bamboo was about three times larger than the grass.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.23-29
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• 2000

Objective: Zona pellucida (ZP) has been thought to be the barrier of egg to sperm penetration before and after fertilization. The phenomenon of ZP hardening has been considered as a post-fertilization event until now, and it is generally accepted that it is caused by the secretory products of cortical granules released during the cortical reaction. Hardening of ZP could occur "spontaneously" in mammalian oocytes in standard culture conditions, and that it is probably not a consequence of cortical reaction. The purpose of our study was to investigate the effect of human amniotic fluid (HAF) on nuclear maturation (NM) and fertilization ability of mouse immature oocytes. Methods: HAF was obtained from patients undergoing amniocentesis at $16{\sim}20$ weeks of gestation. HAF from five to ten patients was centrifuged and the supernatants was pooled. Cumulusenclosed mouse immature oocytes were incubated in the medium containing HAF, and examined to confirm NM and fertilization. Female ICR mice (about 3 weeks old) were stimulated with 7.5 IU PMSG. Immature oocytes were isolated at $48{\sim}52$ hrs post PMSG injection and cultured in TCM-199 supplemented with 20% HAF for 18 hrs. FBS was used as a control for the examination. Matured oocytes (MII) were fertilized with sperms collected from the epididymis of male mice (over 10 weeks old). Fertilization was in conducted T6 medium containing 15 mg/ml BSA, and confirmed at 6 hrs post-insemination. Fertilization rate was assessed in zona-intact or zona-free oocytes (denuded by trypsin). Evaluation of NM and fertilization was carried out by rapid staining method. ZP hardening was evaluated by incubating cumulus cell-free mature oocytes in 0.001% chymotrypsin at $37^{\circ}C$ for 10 min. Results: There was no significant difference between the effects of HAF (86.6%) and FBS (87.7%) supplements on NM of immature oocytes. When maturation medium was supplemented with HAF, total fertilization rates (7%) were significantly lower (p<0.01) than that of FBS (85.1%). In HAF group, fertilization rate was increased (p<0.01) in zona-free oocytes (7% versus 100%). The resistance of mouse oocyte ZP to digestion by chymotrypsin after maturation in vitro was significantly higher (p<0.01) in HAF group (86.7%) than in FBS (6.7%). To culture oocytes in FBS were very effective in preventing ZP hardening. However cultured oocytes in HAF showed high rate of ZP hardening (p<0.01). Conclusions: These results suggest that HAF can be used as a supplement for the NM of mouse immature oocytes in vitro. However, HAF induces spontaneous hardening of ZP of mouse immaure oocytes during maturation in vitro.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.32-32
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• 2017

To increase rice production, manipulating plant architecture, especially developing new high-yielding cultivars with erect leaves, is crucial in rice breeding programs. Leaf inclination angle determines the light extinction coefficient (k) of the canopy. Erect leaves increase light penetration into the canopy and enable dense plantings with a high leaf area index, thus increasing biomass production and grain yield. Because of erect leaves, the high-yielding indica rice cultivar 'Takanari' has smaller k during ripening than 'Koshihikari', a japonica cultivar with good eating quality. In our previous study, using chromosome segment substitution lines (CSSLs) derived from a cross between 'Takanari' and 'Koshihikari', we detected seven quantitative trait loci (QTLs) for leaf inclination angle on chromosomes 1 (two QTLs), 2, 3, 4, 7, and 12. In this study, we developed a near-isogenic line (NIL-3) carrying a 'Takanari' allele for increased leaf inclination angle on chromosome 3 in the 'Koshihikari' genetic background. We compared k, dry matter production, and grain yield of NIL-3 with those of 'Koshihikari' in the field from 2013 to 2016. NIL-3 had higher inclination angles of the flag, second, and third leaves at full heading and 3 (- 4) weeks after full heading and smaller k of the canopy at the ripening stage. Biomass at full heading and leaf area index at full heading and at harvest did not significantly differ between NIL-3 and 'Koshihikari'. However, biomass at harvest was significantly greater in NIL-3 than in 'Koshihikari' due to a higher net assimilation rate at the ripening stage. The photosynthetic rates of the flag and third leaves did not differ between NIL-3 and Koshihikari at ripening. Grain yield was higher in NIL-3 than 'Koshihikari'. Higher panicle number per square meter in NIL-3 contributed to the higher grain yield of NIL-3. We conclude that the QTL on chromosome 3 increases dry matter and grain production in rice by increasing leaf inclination angle.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.47-54
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• 2009

The ballast track, the most common type of conventional railroad track in Korea, is deteriorated by abrasion of ballast, it's penetration into roadbed, and rugged surface of roadbed caused by cyclic loading of train. Persistent occurrence of those phenomena lead to insufficient drain capacity, one of major factors in track design, and it increases pore water pressure and decreases of shear strength under rainfall condition leading to unstable roadbed. In this study, cylindrical model tests are executed for 3 types of geotextile applying cyclic loading in order to observe the characteristics of displacement and bearing capacity of geotextile, and undrained condition has been applied for 0 day, 3 days and 7 days to each geotextiles. The results showed that there was about 1% difference at the final displacement rates between reinforced soils and nature soils and the displacement of the ground surface increases along with the degrees of the saturation. And in case that water contents exceeds the threshold, it is also apparent that weight and tensile strength of geotextile influences displacement of the ground surface. And the larger weight of geotextile is, the smaller plastic displacement. It is evaluated that non-woven fabric comes into effect on reducing the bearing capacity but, the weight of geotextile has little influence on it.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.480-492
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• 2013

After the introduction of geothermal power generation technology based on engineering reservoir creation that can be applied on non-volcanic region, industrial need for studies on the efficient and economic execution of costly deep-depth drilling work becomes manifest increasingly. However, since it is very difficult to predict duration and cost of boring work with acceptable reliability because of many uncertain events during the execution, efficient and organized work management for drilling is not easily achievable. Especially, the round trip that discretely occurs because of the abrasion of bit takes more time as the depth goes deeper and it has a great impact on the work performance. Therefore, a technology that can simulate the occurrence timing and depth of round trip in advance and therefore optimize them is essentially required. This study divided the abrasion state of bit into eight steps for simulation cases and developed a forecast algorithm, i.e., TOSA which can analyze the depth and timing of round trip occurrence. A methodology that can divide a unit section for simulation has been suggested; while the Bourgoyne and Young model has been used for the forecast of drilling rates and bit abrasion extent by section. Lastly, the designed algorithm has been systemized for the convenience of the user.

• Journal of Aquaculture
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• v.20 no.1
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• pp.31-40
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• 2007

To find out the effect of the spat planting time and environmental factors in the arkshell, Scapharca broughtonii (Schrenck), we investigated the growth, survival rate of arkshell and habitat characteristics in Gamak Bay, Yeoja Bay and Saryang Island. We planted artificial spats of arkshell in Gamak Bay and Yeoja Bay at November 2004, and also planted domestic and Chinese natural spats in Saryang Island at March 2005. We measured growth, survival rate of arkshell, physiochemical parameters of the water mass (water temperature, salinity, dissolved oxygen, nutrients and chlorophyll a) and characteristics of the sediment (oxygen penetration depth, oxygen microprofiles, ignition loss and chemical oxygen demand) by monthly. The cumulative survival ratio of arkshell in Gamak Bay was the highest at December, whereas the ratio of arkshell in Yeoja Bay was recorded as 0% at October. The monthly growth rates of arkshell length in Gamak Bay and Yeoja Bay were the highest in May and the growth rate of the Korean arkshell in Saryang Island was higher than Chinese ones significantly. The high mortality (> 65%) of the arkshell in Yeoja Bay during summer probably caused by high water temperature, inflow of low salinity water, and low dissolved oxygen concentration in sediment. The concentrations of nutrient and sediment COD were considered to play an important role in the monthly survival ratio of arkshell in Gamak Bay and Sarayng Island. We suggest that the growth and mortality of arkshell might be influenced to the planting time of spat and the habitat characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.149-158
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• 1998

The SAR patterns of biological objects contacted with coaxial waveguide antennal has been investigated, in which the biological object was modeled by a homogeneous and four-layered lossy human body. We derived the finite-difference time-domain(FDTD) algorithm and equation of MUR and generalized perfectly matched layer(GPML) ABCs in cylindrical coordination. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of MUR and GPML ABCs in the FDTD method to obtain the absorbed power patterns in the media. The specific absorption rates (SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in the FDTD method. The SAR patterns of the FDTD method using MUR absorbing boundary conditions(ABCs) was compared with those of the FDTD method using GPML ABCs. The comparison exhibits that the penetration depth of the SAR patterns using MUR ABCs is deeper than that of the SAR patterns using GPML ABCs because of loss in free space. However, the spread in the lateral directions of the SAR patterns using GPML ABCs is smaller than of the SAR patterns using MUR ABCs.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.216-224
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• 2006

To clarify the formation process and characteristics of oxygen deficient water mass in Gamak Bay, oxygen deficiency was weekly observed from 17 June to 12 September 2005. Surface water temperature was significantly lower in the outer bay than in the inner bay, whereas the bottom water temperature was higher in the central area of bay than in the outer and inner bay. The vertical stratification of water mass was strongly formed during the period, and thermocline was observed between 3 and 5m deep. The oxygen deficiency in the bottom layer began to appear at early July in the inner bay and gradually spread to the center area of the bay in early August. The mean transparency and light attenuation coefficient($K_d$) in water mass was 4.0m and 0.47, respectively. Average concentrations of nutrient and chlorophyll ${\alpha}$ in the bottom layer were significantly higher than those in surface, and those concentrations were significantly higher in the inner bay than in the outer bay. During the formation of oxygen deficiency in the bottom layer, oxygen penetration depth in the bottom sediment were extremely shallow, and oxygen consumption rate in the bottom sediment were lower than that in the area where oxygen deficient water mass disappeared. Dissolved oxygen concentrations in the bottom layer are negatively correlated with nutrient concentrations, whereas those in the surface layer did not show a significant relationship with nutrient concentrations. Elevated loss of oxygen in the bottom water mass was attributed to the increase of the oxygen consumption rates in sediments and the decomposition of organic matter by microorganism.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.188-196
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• 2014

This study aimed to understand the nutrient absorption, usage and allocation of Carpinus cordata in different soil and light environments. Seasonal changes of foliar nitrogen, phosphorous, chlorophyll contents, leaf mass per area (LMA) and nutrient retranslocation rates were investigated for C. cordata saplings growing in a natural deciduous broadleaved forest and an Manchurian fir (Abies holophylla) plantation in Gwangneung, Kyunggido. The deciduous forest had lower leaf area, higher light penetration, and better soil fertility than the Manchurian fir forest. However, available soil phosphorous content in the deciduous forest was only one third of that in the Manchurian fir forest, which caused lower foliar phosphorous content and higher P retranslocation rate of C. cordata in the deciduous forest than that in the Mancurian fir forest. Soil nitrogen contents in the deciduous forest were higher than that in the Manchurian fir forest, however, no differences in foliar nitrogen content and retranslocation rate in C. cordata between the two stands were found. C. cordata in the Manchurian fir forest with high LAI throughout a year, had lower LMA, foliar nitrogen content and chlorophyll a/b, while had higher total chlorophyll content and chlorophyll/N than that in the deciduous forest. These results implied C. cordata under different environments are using different strategies for nutrient use and allocations.