• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.57-66
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• 2013

The purpose of this study was to investigate the effects of shifts in sowing time on the ecological responses, growth and yields of major soybean cultivars in a southern region of South Korea. Experiments were carried out in Naju, Jeonnam Province (latitude $35^{\circ}$ 04'N, longitude $126^{\circ}$ 54'E) for three years from 2008 to 2010. The test cultivars included Saeol-kong and Tawon-kong of the summer type, Taekwang-kong and Pungsannamul-kong, and Cheongja3 of the autumn type. Sowing took place on May 15 and 30, June 15 and 30, and July 15 of each year. Of the summer type soybean cultivars, Saeol-kong showed a smaller curtailment in days from sowing to flowering, days from flowering to maturity, and days from sowing to maturity according to sowing time postponement than Tawon-kong. Of the autumn type soybean cultivars, Taekwang-kong exhibited a lower photoperiodic response in reproductive growth period than Pungsannamul-kong and Cheongja3, both of which recorded higher level photoperiodic responses in vegetative growth stages and reproductive growth periods than other test cultivars, with the former exhibiting higher levels than the latter. Most of the test cultivars tended to decrease in stem length, node numbers of the main stem, and stem diameter according to postponed sowing time, but there were no significant differences in stem length and node numbers of the main stem of the Saeol-kong cultivar. Differences in sowing times did not affect the first setting pod node order of Saeol-kong and Tawon-kong summer type cultivars of internode lengths of all of the test cultivars. All of the test cultivars tended to show decreases in pod number per plant due to postponement of sowing time except for the Saeol-kong cultivar. The variation was more prominent in small grain cultivars such as Tawon-kong and Pungsannamul-kong with the latter autumn type cultivar showing especially large variation. Yields were the greatest for the Tawon-kong, Taekwang-kong, and Pungsannamul-kong cultivars sown on May 30 and Cheongja3 sown on May 30 and June 15. There were no significant differences in the yields of Saeol-kong for different sowing times from May 30 to July 15, with the yields lowest for the batch sown on May 15.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.288-294
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• 2011

BACKGROUND: Methylmercury is analyzed by HPLC-ICP/MS because of the simplicity for sample preparation and interference. However, most of the pre-treatment methods for methylmercury need a further pH adjustment of the extracted solution and removal of organic matter for HPLC. The purpose of this study was to establish a rapid and accurate analytical method for determination of methylmercury in fish by using HPLC-ICP/MS. METHOD AND RESULTS: We conducted an experiment for pre-treatment and instrument conditions and analytical method verification. Pre-treatment condition was established with aqueous 1% L-cysteine HCl and heated at $60^{\circ}C$ in microwave for 20 min. Methylmercury in $50{\mu}L$ of filtered extract was separated by a C18 column and aqueous 0.1% L-cysteine HCl + 0.1% L-cysteine mobile phase at $25^{\circ}C$. The presence of cysteine in mobile phase and sample solution was essential to eliminate adsorption, peak tailing and memory effect problems. Correlation coefficient($r^2$) for the linearity was 0.9998. The limits of detection and quantitation for this method were 0.15 and $0.45{\mu}g/kg$ respectively. CONCLUSION: Result for analytical method verification, accuracy and repeatability of the analytes were in good agreement with the certified reference materials values of methylmercury at a 95% confidence level. The advantage of the established method is that the extracted solution can be directly injected into the HPLC column without additional processes and the memory effect of mercury in the ICP-MS can be eliminated.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.895-900
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• 2001

Background : This study aimed to evaluate the usefulness of preoperative placement of intraaortic balloon pump(IABP) in reducing operative risk and facilitating posterior vessel OPCAB in high risk patients with left main disease( 75％ stenosis), intractable resting angina, postinfarction angina, or left ventricular dysfunction(ejection fraction 35％). Material and Method : One hundred eighty- nine consecutive patients who underwent multi-vessel OPCAB including posterior vessel revascularization were studied. The patients were divided into group I(n=74) that received preoperative or intraoperative IABP and group II(n=115) that did not receive IABP. In group I, there were 39 patients with left main disease, 40 patients with intractable resting angina, 14 patients with left ventricular dysfunction and 7 patients with postinfarction angina. Ten patients received intraoperative IABP support due to hemodynamic instability during OPCAB. Result : There was one operative mortality in group I and two mortalities in group II. The average number of distal anastomoses was not different between group I and group II(3.5$\pm$0.9 vs 3.4$\pm$0.9, p=ns). There were no significant differences in the number of posterior vessel anastomosis per patient between the two groups. There were no differences in ventilator support time, length of hospital stay, and morbidity between the two groups. There was one case of IABP-related complication in group I. Conclusion : IABP facilitates posterior vessel OPCAB in high risk patients, with comparable surgical results to low risk patients

• Radiation Oncology Journal
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• v.20 no.3
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• pp.193-198
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• 2002

Purpose : Oligodendrogliomas (ODG) are a rare, slow growing, tumor in the brain, which can be cured by complete surgical resection, but as yet it is not known if postoperative adjuvant radiation therapy (RT) is essential, We analyzed the treatment results of patients with irradiated ODG to investigate the efficacy of RT in terms of survival rates and other influencing prognostic factors. Methods and Materials : Between March 1983 and December 1997, 42 patients with ODG were treated with RT at our hospital. The RT was peformed dally at a dose of $1.8\~2.0\;Gy$, at 5 fractions per week, to a total dose of between 39.6 Gy and 64.8 Gy (mean 53.3 Gy). The ages of the patients ranged between 5 and 62 years, with a median age of 39 years. The mean follow-up period was 63.4 months (8-152 months). The Kaplan-Meier method was used to assess the survival, and 5 year survival rates (5-YSR). Log rank tests and Cox regression analyses were used to define the significance of prognostic factors. Results : The majority of ODG in this study were located in the cerebral hemisphere $(83.3\%)$. ODG are slightly more common in men than women, and commonly occurs in middle age, between the 3rd and 4th decades. It has been recommended that RT is commenced within 4 weeks following surgery (5-YSR; $86\%\;vs.\;49\%;\;p<0.03$). Histologically well differentiated, as opposed to poorly differentiated, tumors were found to have a more favorable prognosis (p<0.02). The actuarial 5-YSR was $65.3\%$ (median survival 90 months). 5-YSR for the various extents of surgical excision, followed by external RT, was superior to that of biopsy only followed by external RT $(69.9\%\;vs.\;25.6\%,\;p<0.01)$. Tumor size and location, overall elapsed irradiation days, age, sex, whole brain irradiation as a course of treatment and chemotherapy, had no influence on the 5-YSR (p>0.05). Conclusion : A local involved field irradiation with conventional fractionation, commencing within 4 weeks following surgical excision of the tumor, was beneficial for the 5-YSR, but a total radiation dose exceeding 60 Gy did not improve the 5-YSR.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.135-142
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• 2011

Purpose : Hospital associated infection (HAI) caused by multidrug-resistant (MDR) microorganisms has been recognized as an important issue in the world, especially in critically ill patients such as the patients admitted in the intensive care unit. There are fewer papers about MDR-HAI in pediatric patients compared to adult patients. In this study, we investigated the incidence and associated factors of MDR-HAI in children admitted to the intensive care unit (ICU) of a university hospital. Methods : We retrospectively evaluated 135 children who were admitted in ICU for at least 3 days between January 2009 and December 2010. HAI cases were divided into MDR-HAI group and non-MDR-HAI group. Clinical characteristics and various associated factors were compared between those groups. Results : In 39 patients, 45 cases of ICU-related HAI were developed. ICU-related HAI incidence was 47.7 per 1000 patientdays. Thirty-six cases (80.0%) were MDR-HAI. Acinetobacter baumannii was isolated more commonly in MDR-HAI group. And the followings were found more frequently in MDR-HAI group than non-MDR-HAI group: medical condition as an indication for ICU admission, mechanical ventilation, urinary catheterization and previous use of broad-spectrum antibiotics. Among the risk factors, previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. Conclusion : ICU-related HAI incidence was higher than previously reported. Previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. To investigate the characteristics of MDR-HAI in children admitted in ICU, further studies with a larger sample size over a longer period of time are warranted.

• Journal of Life Science
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• v.18 no.4
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• pp.515-521
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• 2008

This experiment was conducted to investigate effects of non-ionic or zwitterionic (+/-) surfactants on digestibility of rice straw, and changes of growth of rumen mixed microbes, pH, and gas production during in vitro fermentation. Also, during in vitro ruminal fermentation, microbial attachment on rice straw was investigated using scanning electron microscopy (SEM). Tween 80 or SOLFA-850 for non-ionic surfactant (NIS), and 3-(Dodecyldimethylammonio) propanesulfanate (DDAP) for zwitterionic surfactant (ZIS) was supplemented by 0.05% and 0.1% in Dehority's artificial medium containing Holtein rumen fluid, respectively, and the substrate for fermentation was rice straw passed through 1 mm screen. The experiment was composed of 7 treatments (two levels of two NISs, two levels of a ZIS) including the control, and 6, 12, 24, 48 and 72 hr of fermentation time with 3 replications per treatment. Treatment of Tween 80 increased in vitro DM digestibilities during 48 hr and 72 h post fermentations compared to the other treatments, whereas treatment of DDAP as a ZIS resulted in decreased DM digestibility than that of the control from 24 hr post fermentation (P<0.05). Gas production in vitro was greater (P<0.05) with addition of NIS than the control or ZIS, and increased as fermentation time elapsed. Rumen mixed microbial growth was greatest with addition of Tween 80 as NIS, and lowest when DDAP as ZIS was supplemented to the fermentation tube (P<0.05). In SEM observation, rumen microbial population attached on rice straw particle was greater with addition of NIS, but was less with addition ZIS compared with the control. In conclusion we could not found any positive effects of ZIS surfactants on rumunal fermentation characteristics and rumen microbial growth rates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.1
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• pp.21-25
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• 2014

Singwangok, a new single cross variety, was developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2012. This hybrid, consisting of a high yield of grain, was produced by crossing two inbred lines, KS172 and KS173. KS172 is the seed parent and KS173 is the pollen parent of Singwangok. It is a yellow-orange intermediate maize hybrid (Zea mays L.). After the preliminary yield trial and advanced yield trial of Singwangok (Suwon185) in Suwon for 2 years, the regional yield trial of that was subsequently carried out for its growth characteristics and yield at 3 different locations from 2010 to 2012. It was named as Singwangok. The silking date of Singwangok is similar to the check hybrid, Jangdaok. The plant height of Singwangok is similar to Jangdaok, but its ear height ratio is lower than that of Jangdaok. Moreover, it has a resistance to lodging. The ear number per 100 plants of Singwangok is more 17 than that of Jangdaok, whereas the ear length of Singwangok is similar to Jangdaok. Further, the weight of 100 seeds of Singwangok is similar to Jangdaok. It has a moderate resistance to southern leaf blight (Bipolaris maydis) and a strong resistance to northern leaf blight (Exserohilum turcicum). Furthermore, it has a moderate resistance to the black streaked dwarf virus (BSDV), ear lot and corn borer. The grain yield of Singwangok, 7.81 ton/ha, was similar to that of Jangdaok. The seed production of Singwangok was well processed due to the good match during crossing between the seed parent, KS172 and the pollen parent, KS173, in Yeongwol; the F1 seed yield was 3.84ton/ha. Singwangok would be a suitable cultivar to all plain areas in Korea.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.338-343
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• 2019

This study was conducted to nominate optimal ground cover plants eventually enhancing Aronia production in the highland rolling plains. Total number of 17 weed species were observed in Aronia field when no cover plant was applied. Meanwhile, 12, 14, 15 and 16 weed species were observed when kentucky bluegrass, white clover, rattail fescue and ground ivy were used, respectively. Untreated native weed species were 73.6 cm tall before cut, and kentucky bluegrass, white clover, Rattail fescue and ground ivy were 57.5, 36.8, 48.3 and 40.9 cm, respectively. Based on plant height before cut, two shortest plants, white clover and ground ivy, were considered effective as ground cover plants in Aronia field. Coverage at $3^{rd}$ year by cover plants ranged from 85% to 100%. Coverage of uncovered Aronia field by native weed species was 95% while coverage by 4 treatments, kentucky bluegrass, white clover, rattail fescue and ground ivy were 100, 87, 85 and 100%, respectively. Aronia yield per plant at $3^{rd}$ year was 1,916 g with white clover cover followed by 1,770 g with Rattail fescue, 1,766 g with ground ivy, 1,098 g without cover plants and 931 g with Kentucky Bluegrass. Out results indicated that ground ivy was the best among all treatments based on 3 criteria, (1) short plant architecture, (2) rapid ground covering and (3) better weed control. In addition, ground ivy cover appeared to secure better yield.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.448-454
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• 2021

This study was conducted to the effect of low air temperature and light intensity conditions on yield and quality of tomato at the early stage of growth in Korea. Inplastic greenhouses, low temperature and low temperature with shade treatments were performed from 17 to 42 days after plant. Tomato growing degree days were decreased 5.5% due to cold treatment during the treatment period. Light intensity decreased 74.7% of growing degree days due to shade. After commencing treatments, the plant growth decreased by low temperature and low radiation except for height. Analysis of the yield showed that the first harvest date was the same, but the yield of the control was 3.3 times higher than low temperature with shade treatment. The cumulative yields at 87 days after transplanting were 1734, 1131, and 854 g per plant for control, low temperature, and low temperature with shade, respectively. The sugar and acidity of tomatoes did not differ between treatment and harvesting season. To investigate the photosynthetic characteristics according to the treatment, the carbon dioxide reaction curve was analyzed using the biochemical model of the photosynthetic rate. The results showed that the maximum photosynthetic rate, J (electric transportation rate), TPU (triose phosphate utilization), and R_d (dark respiration rate) did not show any difference with temperature, but were reduced by shading. Vcmax (maximum carboxylation rate) was decreased depending on the low temperature and the shade. Results indicated that low temperature and light intensity at the early growth stage can be inhibited the growth in the early stage but this phenomenon might be recovered afterward. The yield was reduced by low temperature and low intensity and there was no difference in quality.

• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.322-340
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• 2021

Due to climate change and its consequential spring temperature rise, flowering time of Robinia pseudoacacia has advanced and a simultaneous blooming phenomenon occurred in different regions in South Korea. These changes in flowering time became a major crisis in the domestic beekeeping industry and the demand for accurate prediction of flowering time for R. pseudoacacia is increasing. In this study, we developed and compared performance of four different models predicting flowering time of R. pseudoacacia for the entire country: a Single Model for the country (SM), Modified Single Model (MSM) using correction factors derived from SM, Group Model (GM) estimating parameters for each region, and Local Model (LM) estimating parameters for each site. To achieve this goal, the bloom date data observed at 26 points across the country for the past 12 years (2006-2017) and daily temperature data were used. As a result, bloom dates for the north central region, where spring temperature increase was more than two-fold higher than southern regions, have advanced and the differences compared with the southwest region decreased by 0.7098 days per year (p-value=0.0417). Model comparisons showed MSM and LM performed better than the other models, as shown by 24% and 15% lower RMSE than SM, respectively. Furthermore, validation with 16 additional sites for 4 years revealed co-krigging of LM showed better performance than expansion of MSM for the entire nation (RMSE: p-value=0.0118, Bias: p-value=0.0471). This study improved predictions of bloom dates for R. pseudoacacia and proposed methods for reliable expansion to the entire nation.