• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.155-160
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• 1987

This study was carried out to determine the effects of cryoprotectants, freezing and thawing rates on the survival of 8-cell mouse embryos. The female ICR mice were induced to superovulated by intraperitoneal injections of 5 i.u. PMSG and 5 i.u. HCG given 48h apart and then were paired with males of the same strain. They were killed and embryos were flushed from the oviducts and uteri on 3 days after injection of HCG. Embryos were flushed with modified Dulbecco's phosphate buffered saline and equilibrated with 1.5M-dimethyl sulfoxide (DMSO) or 1.5M-glycerol by 3-step procedure. The freezing rates of the embryos were 1$^{\circ}C$/min from room temperature to -5$^{\circ}C$ and the embryos were seeded at -5$^{\circ}C$. After being held for 3 min at the seeding temperature, the rates were 0.3$^{\circ}C$/min from -5$^{\circ}C$ to -35$^{\circ}C$. From -35$^{\circ}C$ to -7$0^{\circ}C$, the rates were divided into 0.1$^{\circ}C$/min, 1$^{\circ}C$/min and 1$0^{\circ}C$/min, respectively. After being held for 5 min at -7$0^{\circ}C$, the embryos were plunged directly into liquid nitrogen. The embryos were thawed at 4$^{\circ}C$/min and 12$^{\circ}C$/min from -196$^{\circ}C$ to 37$^{\circ}C$, and for 2 min in 37$^{\circ}C$ water bath, respectively. The average number of ovulation points and embryos recovered were 42.7 and 34 appearing 79.5% recovery rate. Eight cell embryos in the embryos recovered were 26.3. The survival rates of embryos according to the freezing rates in the presence of 1.5M-DMSO were 73.5~80.6% at 0.1$^{\circ}C$/min, 75.0~79.5% at 1$^{\circ}C$/min and 52.8~54.7% at 1$0^{\circ}C$/min, but in the presence of 1.5M-glycerol were 62.9~67.6% at 0.1$^{\circ}C$/min, 61.4~68.3% at 1$^{\circ}C$/min and 25.5~30.2% at 1$0^{\circ}C$/min. The survival rates of embryos were not affected by the thawing rates.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.180-186
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• 2001

Purpose: The prognosis for early gastric cancer (EGC) is favorable, and the 10-year disease-specific survival rate is reported to be around $90\%$. The absolute number of recurred EGC is too small to assess the risk factors, so recruitment of a large number of cases for statistical analysis is very difficult. We carried out this study to analyze the incidence and the patterns of recurrence of EGC and to identify the clinicopathological risk factors for recurrence of EGC. Materials and Methods: The authors retrospectively investigated the follow-up records of 1418 patients who underwent a curative resection for EGC from Jan. 1984 to Dec. 1999 at the Korea Cancer Center Hospital and analyzed them with special reference to cancer recurrence. Results: In this retrospective study of 1418 cases, 43 patients died of a recurrence of gastric cancer, and 105 patients died of unrelated causes. The five-year and the ten-year overall survival rates were $89.6\%$ and $81.7\%$, respectively, while the five-year and the ten-year diseasespecific survival rates were $96.5\%$ and $94.3\%$, respectively. The recurrence patterns of the 45 recurred EGC were hematogenous metastasis (19 cases), lymph node (L/N) metastasis (8 cases), locoregional recurrence (2 cases), peritoneal seeding (3 cases), and combined form (13 cases). The mean time interval to recurrence was 38.6 months, and the number of delayed recurred cases after 5 years was 10 ($22.2\%$). Of the clinicopathologic factors, depth of invasion, L/N metastasis, macroscopic type, lymphatic invasion, and vessel invasion, were significant risk factors in the univariate analysis. However, in the multivariate analysis, only L/N metastasis was an independent prognostic factor. Conclusion: Based on the results of this study, L/N metastasis is an independent prognostic factor. Thus, in patients with node-positive disease, adjuvant therapy might be considered, and long-term close follow-up might facilitate early detection and treatment of recurrent disease due to delayed recurrence.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.234-234
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• 2017

Recent abnormal weather, especially continued rainfall during sowing season causes difficulty in proper sowing of wheat and delayed sowing after November 15 is concerned about freezing damage during winter, resulting in reduction of wheat yield. To correspond government policy of crop sufficiency improvement and produce and supply raw wheat and barley steadily, expansion of cultivation area is necessary and spring sowing of wheat is required. To obtain basic information on the improvement of spring sown wheat and barley production, comparison and path coefficients analysis was conducted for yield and yield related components from autumn and spring sown wheat and barley. Path analyses were known as very useful in clarifying the effects of yield components on grain yield formation, which were not accurately reflected in simple correlation anaylses. Most cultivated 5 wheat and 9 barley cultivars were sown on October and February at Cheon-ju province according to standard sowing method. For the spring sowing of wheat and barley, the varieties having vernalization degree I~III are seeded in the mid of February and seeding rate is 200~250kg/ha which is increased by 25% than autumn sowing. N-fertilizer of 95 kg/ha and the same amount of P, K dressed in autumn are applied at once as basal fertilizer. The magnitude of direct effect in each yield components on yield was in sequence as follows. In autumn wheat, grain number per $spike{\geq}$ the number of spike per $m^2$>1000-grain weight and in spring wheat, grain number per $ spike{\geq}the$ number of spike per $m^2$> 1000-grain weight. In autumn naked barley, 1000-grain weight> the number of spike per $m^2$, grain number per spike and in spring barely, the number of spike per $m^2$> grain number per spike > 1000-grain weight. In autumn covered barley, grain number per spike>the number of spike per $m^2$ and in spring coverd barley, the number of spike per $m^2$> grain number per spike, 1000-grain weight. In autumn malt barley, the number of spike per $m^2$>1000-grain weight and in spring malt barley, the direct effects of three yield components were similar. According to the path analysis of yield components for spring sown wheat and barley, it was suggested that adequate number of spike per $m^2$ was most important factor for yield increase.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.332-337
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• 2004

A suspected biotype of Scirpus planiculmis to be resistant to sulfonylurea(SU) herbicides was identified in Seosan reclaimed paddy fields in Korea, in 2004. The fields have been cultivated for monocultural rice production with wet-direct seeding method and continuously treated with SU-based herbicide mixtures for thirteen years since 1990. In greenhouse studies, 6 different SU herbicides, such as azimsulfuron, bensulfuron-methyl, cinosulfuron, ethoxysulfuron imazosulfuron and pyrazosulfuron-ethyl, completely controlled the Musan assession of Scirpus planiculmis at the recommended dose of each herbicide, however, the Seosan accession of S. planiculmis biotype was survived 20 to 45% even treated with 5 times higher dose of each recommended rate of all herbicides treated. The $GR_{50}$ values of 6 SU herbicides for Seosan accession of S. planiculmis were 47 to 100 times higher than those for Musan accession of S. planiculmis. The $I_{50}$ values pyrazosulfuron-ethyl to acetolactate synthase(ALS) extracted from Sesan and Muan accession of S. planiculmis were 409 nM and 0.8 nM, respectively. The $I_{50}$ value of Seosan was 511 times higher than that of Muan accession. These results suggested that the Seosan accession of S. planiculmis have strong resistant characteristics to 6 SU herbicides, respectively, indicating that resistance might be due to the alteration in the target site of ALS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.502-511
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• 1994

Investigated were the relationships between plumule elongation characteristics and seedling emergence of 98 varieties including native, improved and red rice varieties of Korea, and varieties from U.S.A., Italy, Japan, etc. under proper and excess soil moisture regimes. Under excess soil moisture condition the seedling emergence and establishment rates were much lower in most of the varieties and the seedling emergence rates were delayed substantially in all varieties employed. The seedling emergence rates were lowest in dwarf and some semi-dwarf varieties showing poor plumule elongation under proper soil moisture condition. The seedling emergence and establishment rates were significantly correlated with the length of mesocotyl, coleoptile and incomplete leaf under both soil moisture regimes, and with the lower first and second internode length under excess soil moisture condition. Average emergence duration showed significant negative correlation with the length of mesocotyl, coleoptile and incomplete leaf under both soil moisture regimes and significant positive correlations with the first and third lower internode length. Based on the standardized partial regression analysis only the variations of mesocotyl and coleoptile length contributed significantly to the varietal difference in seedling establishment rate, and so did the variations of mesocotyl and incomplete leaf length to the varietal differences in emergence speed. In conclusion varieties with greater elongation characteristics of mesocotyl, coleoptile and incomplete leaf are desirable for higher and speedy seedling establishment in dry-direct seeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.16-21
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• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.123-128
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• 2007

A study was conducted over two years to determine the temperate mixtures of grasses for grazing horses in Jeju, Korea. The experiment field located at 450 m altitude (Jeju Horse Training Center of Korea Racing Association) was divided into 3 different mixtures plots (3 replications) without a fence between treatments, and sown by three main grasses (orchardgrass, perennial ryegrass and timothy). Seven castrated adult horses were kept on pasture from the middle of April to the end of November without supplementary concentrates. The dry matter yield, percentage of grasses intake and botanical composition were determined during the grazing period. Nutrients in grasses and soils were analyzed. The dry matter yield during two-year experimental period was not different among mixtures (11,000-12,000 kg/ha/year). In botanical composition, perennial ryegrass was dominant in all mixtures during spring through early summer season, but faded away during hot summer season. Timothy seemed to be more resistant against a hot or dry weather than other grasses. The percentage of grasses intakes was higher in the mixture of timothy than those in other mixtures. The contents of NDF (neutral detergent fiber) and ADF (acid detergent fiber) were not different among different mixtures. These results indicate that the mixture of timothy, orchardgrass, perennial ryegrass and white clover (20, 5, 5, 2 kg/ha as a seeding rate) can be used for gazing pasture of horses in the high altitude of Jeju.

• Asian Journal of Turfgrass Science
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• v.18 no.1
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• pp.1-13
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• 2004

The growth characteristics of cool season turfgrass in the seaside landfill golf courses with the single-use of kentucky bluegrass and mixed-use with kentucky bluegrass and perennial ryegrass in the coast line are as follows. Water infiltration rate was higher in the kentucky bluegrass single-use groups recorded as 95.6∼125.9cm/hr than in the roups mixed with kentucky bluegrass and perennial ryegrass recorded as 180.3∼386.2cm/hr. The surface soil hardness and the soil penetration were ranged from 16.6 to 18.0mm and from 6.0 to 7.3kg/cm$^2$, respectively. The cultivar that showed the most excellent visual quality and visual color in the kentucky bluegrass single-use groups was Midnight(KB2), whose density around the root was relatively excellent, as well. North Star(KB3) known as highly resistant to salt was the secondarily excellent cultivar. Brilliant(KB1) had visual quality of about third grade, however, it seemed profitable to develop turfgrass ground by virtue of its high density. As of April 26, 2003, when 2 weeks had passed after seeding, the visual quality was better in the groups mixed with kentucky bluegrass and perennial rye grass than in the kentucky bluegrass single-use groups. The most excellent visual color was found in Midnight(KB2)+Brightstar SLT(PR2) among the groups mixed with kentucky bluegrass and perennial ryegrass. On August 4, 2003, a disease was found from one experimental group in Blackstone(KB4) and expanded into more than 50cm of diameter.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.491-510
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• 1996

This study was performed to evaluate the effects of platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) on the characteristics of beagle dog's periodontal ligament (BPD) cells and bone marrow (BBM) cells which have the important role on the early stage of periodontal tissue regeneration in vitro. In control group, the cells ($1.5{\times}10^5$cells/ml) were cultured alone with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, $50{\mu]g/ml$ ascorbic acid, and 10mM/ml ${\beta}-glycerophosphate$. In experimental groups, growth factors, PDGF or EGF(10ng/ml), were added into the above culture condition. And then each group was characterized by examining the cell proliferation rate, amount of total protein synthesis, alkaline phosphatase activity at 1, 5, 9, 13, 17th day after seeding of cells into the culture wells. The results were as follows: 1. Both BPD and BBM cells in PDGF-treated group proliferated more rapidly than non-treated cells. This finding also was observed in EGF-treated group but it was not as prominent as that of PDGF-treated group. The proliferation rates of both cells showed the time-dependent pattern during experimental periods in all three groups. 2. Amount of total protein synthesis was more increased in PDGF-treated group than in control group. But no significant difference between EGF-treated group and control group was observed throughout experimental periods even though the tendency of amount of protein synthesis was time-dependent pattern. 3. Alkaline phosphatase activity also more increased in PDGF-treated group than control group. But slight decrease tendency was seen in both cells of EGF-treated group. From the above results, PDGF appeared to enhance the proliferation and cellular activities including amount of total protein synthesis and alkaline phosphatase activity of BPD and BBM cell, but EGF did not show notable effects. The optimal application of these growth factors was thought to be useful as the adjunctive means in periodontal regeneration procedures.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.153-158
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• 1982

The study was conducted to obtain the basic information on the diseases epidemics of vegetable crops grown in Namji, Jinju, Gimhae and Suncheon under the extremely varied and specified conditions, plastic film house. The disease survey was conducted from the end of April, 1951 to April 1982. Leaf mold and late blight were serious foliar disease in tomato during the seedling stage, especially when the infected seeds were sown. The diseases increased rapidly 35 days after seeding. In both continuous cultivation of cucumber and rotation with upland crops, incidence of Fusarium wilt was severe while incidence of the disease was negligible in cultivations after paddy rice or grafting on pumpkin. Downy mildew of cucumber was severe in Jinju and Suncheon area, however, it was not so serious in Namji area where the growing season of cucumber was unfavorable for the maximum disease incidence. Cucumber mosaic virus disease was prevalent in the areas surveyed and the disease incidence was increased rapidly after June. Powdery mildew prevailed at the early stage of cucumber growth after transplanting in Namji area. Root rot and wilting caused by Phytophthora capsici was as the most destructive disease in pepper grown under the vinyl house, especially in Namji and Jinju area where the pepper has been cultivated intensively. The Phytophthora attacked most parts of young plants during the winter time and then induced crown rot on the adults plants. Cultivation of pepper in vinyl house was almost impossible because of the Phytophora disease by the end of June. Virus diseases to tomato plants were prevalent throughout the surveyed area and the damage was also severe. In Jinju and Gimhae area leaf mold and late blight showed high infection rate in tomato during the harvest time.