• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.9-17
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• 2011

Positive effect of multiple-PGPR (Plan Growth Promoting Rhizobacteria), isolated from heavy metal contaminated soil, on the germination of Barnyard grass (Echinochloa crus-galli var. frumentacea) was quantitatively estimated in 5 heavy metal (Cd, As, Ni, Cu, and Pb) contaminated liquid medium. The $EC_{50}$ value for respective heavy metal was estimated by TSK (Trimmed Speraman-Karber) model based on germination rate. The results showed overall increase in $EC_{50}$ with PGPR inoculation. The $EC_{50}$ value increased 1.4% from 96.0 mg/L (control) to 97.4 mg/L (PGPR-treated) in As contaminated medium. In Ni contaminated medium, the $EC_{50}$ value increased 31.9% from 148.0 mg/L (control) to 195.2 mg/L (PGPR-treated), while the $EC_{50}$ showed 4.8% increase from 63.4 mg/L (control) to 66.5 mg/L (PGPR-treated) in Cu medium. Overall seedling growth was stronger in the PGPR treated seeds than that in the control, but positive effect on seedling growth was not conspicuous. At effective concentration of 100 mg/L, the average seedling length of the PGPR treatment in As, Cd, Cu, and Ni medium, respectively, was 1.13, 0.14, 0.40, and 0.06 cm longer than that in the control. However, the increase of seedling growth was statistically insignificant (p < 0.05). These results suggest that inoculation of the isolated-PGPR exerts positive effects on seed germination by reducing heavy metal toxicity and can be an effective tool for application of phytoremediation on heavy metal contaminated soils.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.485-489
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• 1995

The medium additives such as fatty acid, lipid, mannose, folic acid, $CaCl_2$ were examined to enhance recombinant ${\beta}-galactosidase\;({\beta}-gal)$ production in T-flask and air-lift bioreactor. The addition of each component. such as cholesterol, tocopherol, tricaprylin, mannose and folic acid at AcNPV infection of Tn5B1-4 cells enhanced ${\beta}-gal$ production, whereas the addition of $CaCl_2$ did not increase ${\beta}-gal$ production. The recombinant ${\beta}-gal$ production using the infection medium supplemented with a mixture of 0.34 mM cholesterol, 2.2 mM mannose and 0.045 M folic acid was enhanced 2 fold in an air-lift bioreactor, compared to the basal medium.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.235-239
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• 2004

We studied the effect of genotype, explant, age of explant, medium (plant growth regulators and gelling agents), and standardized an efficient regeneration protocol for inbred lines of Chinese cabbage (Brassica rapa ssp. pekinensis). Of the different concentrations of NAA and BA tested, the combination of $5\;\cal{mg/L}\;BA\;and\;0.5\;\cal{mg/L}$ NAA gave the highest frequency of shoot regeneration. The cotyledonary explants had more shoot regeneration frequency ($\ge40\%$) than the hypocotyl ex-plants. Besides, the cotyledonary explants, excised from the 4-day old seedlings, showed higher shoot regene-ration ($56.7\%$). Of the three gelling agents and their concentrations used, 16 g/L agar was found to be the best for shoot regeneration. Shoot regeneration frequency in-creased significantly by supplementing the medium with $4\;\cal{mg/L}\;of\;AgNO_3$ MS medium devoid of NAA showed higher frequency of rooting in the regenerated shoots than the ones supplemented with NAA. Our improved regeneration protocol will be especially useful for the genetic transformation of Chinese cabbage inbred lines to develop transgenic hybrids.

• Journal of Korean Academy of Nursing
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• v.50 no.4
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• pp.621-630
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• 2020

Purpose: This study was aimed to evaluate the external validity of a carbapenem-resistant Enterobacteriaceae (CRE) acquisition risk prediction model (the CREP-model) in a medium-sized hospital. Methods: This retrospective cohort study included 613 patients (CRE group: 69, no-CRE group: 544) admitted to the intensive care units of a 453-beds secondary referral general hospital from March 1, 2017 to September 30, 2019 in South Korea. The performance of the CREP-model was analyzed with calibration, discrimination, and clinical usefulness. Results: The results showed that those higher in age had lower presence of multidrug resistant organisms (MDROs), cephalosporin use ≥ 15 days, Acute Physiology and Chronic Health Evaluation II (APACHE II) score ≥ 21 points, and lower CRE acquisition rates than those of CREP-model development subjects. The calibration-in-the-large was 0.12 (95% CI: - 0.16~0.39), while the calibration slope was 0.87 (95% CI: 0.63~1.12), and the concordance statistic was .71 (95% CI: .63~.78). At the predicted risk of .10, the sensitivity, specificity, and correct classification rates were 43.5%, 84.2%, and 79.6%, respectively. The net true positive according to the CREP-model were 3 per 100 subjects. After adjusting the predictors' cutting points, the concordance statistic increased to .84 (95% CI: .79~.89), and the sensitivity and net true positive was improved to 75.4%. and 6 per 100 subjects, respectively. Conclusion: The CREP-model's discrimination and clinical usefulness are low in a medium sized general hospital but are improved after adjusting for the predictors. Therefore, we suggest that institutions should only use the CREP-model after assessing the distribution of the predictors and adjusting their cutting points.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.171-175
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• 1998

Chinese foxglove (Rehmannia glutinosa) is receiving much attention as one of the principal medicinal crops and the crude drug damand expands rapidly.This study was conducted to obtain the basic breeding information of Chinese foxglove. Effects of supplemental plant growth regulators were investigated on leaf tissue for proliferation. 100% callus formation, 31% plantlet regeneration and 6% root differentiation were obtained by adding 0.5 mg/L NAA and 2.0 mg/L BA. 2,4-D and Zeatin treatment also resulted in 95% increase in callus formation, but shoot was not formed. During the subculture, callus propagation rate recorded 15.4% with 0.2 mg/L NAA and 1.0 mg/L BA and plant regeneration improved on MS medium supplemented with 0.2 mg/L NAA and 0.5 mg/L kinetin. The number of shoot formed ranged from 1.7 on WPM medium to 3.4 on MS medium with 0.1 mg/L NAA and 0.5 mg/L BA. Supplementation of 1.0 g/L activated charcoal improved the In vitro plant growth.

• Journal of the Korea Society of Computer and Information
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• v.6 no.2
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• pp.84-89
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• 2001

In this paper, an improved protocol of Multi-Link Switching Method is proposed by supplementing a concurrent processing function. This protocol is proposed to complement the shortcomings of the conventional Multi-Link Switching Method which is used for the medium access in LAN. We analyzed the improved protocol in channel utilization viewpoint and compared the result with that of the conventional protocol From this result, we showed that the channel utilization of the improved protocol is superior to that of the conventional protocol when the maximum normalized propagation delay is increased.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.361-362
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• 2015

This paper proposes a Direct Power Control (DPC) scheme of improved command tracking capability for Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) Wind Turbines. Benchmarking is performed based on a neutral point clamped three-level back-to-back type voltage source converter. It is introduced to design the DPC modeling and propose DPC scheme of a three-level NPC (3L-NPC) converter. During the fault condition in wind farms, the proposed control scheme directly controls the generated output power to the command value from the hierarchical wind farm controller. The proposed control scheme is compared with conventional control scheme as respect to loss and thermal analysis. The DPC scheme of improved command tracking capability is confirmed through PLECS simulations. Simulation result shows that proposed control scheme achieves a much shorter transient time in a step response of generated output power. The proposed control scheme makes it possible to provide a good dynamic performance for PMSG MV wind turbine to generate a high quality output power under grid fault condition.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.494-504
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• 2010

The effect of the addition of the fresh medium, volume of under solid medium in double layer culture as well as the medium change after pretreating microspores on the production of embryos in microspore culture of hot pepper (Capsicum annuum L.) has been studied. When cultured after heat pre-treatment, changing pretreatment media with fresh culture media proved to be more effective for embryo production rather than supplementing additional culture media. Heat-pretreating for 3 days turned out more effective for embryo production than pretreating for 1 or 2 days. In the case of anther pretreatment, the addition of fresh medium after culture was not effective for embryo production. In pretreating microspores, however, supplementing additional fresh culture media greatly improved embryo yield and quality. The best time point of media addition was 4 days after culture commenced, and the most effective number of times of media addition was one time addition. Moreover, the effective volume of added medium in double layer culture for embryo production was 1.5 ml. The addition of media more than 1.5 ml reduced both embryo yield and quality. Double layer medium was more effective for embryo development than liquid medium. When the volume of under solid medium increased ranging from 3 ml to 7 ml, more cotyledonary embryos were produced in either 5 ml or 7 ml compared to 3 ml, even though the total number of embryos were highest in 3 ml. These results can be used as an important data for establishing an efficient microspore culture system for producing high frequency of normal embryos in hot pepper.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.630-637
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• 2022

The objective of this study was to optimize industrial-grade media for improving the biomass production of Weissella cibaria JW15 (JW15) using a statistical approach. Eleven variables comprising three carbon sources (glucose, fructose, and sucrose), three nitrogen sources (protease peptone, yeast extract, and soy peptone), and five mineral sources (K₂HPO₄, potassium citrate, ⳑ-cysteine phosphate, MgSO₄, and MnSO₄) were screened by using the Plackett-Burman design. Consequently, glucose, sucrose, and soy peptone were used as significant variables in response surface methodology (RSM). The composition of the optimal medium (OM) was 22.35 g/l glucose, 15.57 g/l sucrose, and 10.05 g/l soy peptone, 2.0 g/l K₂HPO₄, 5.0 g/l sodium acetate, 0.1 g/l MgSO₄·7H₂O, 0.05 g/l MnSO₄·H₂O, and 1.0 g/l Tween 80. The OM significantly improved the biomass production of JW15 over an established commercial medium (MRS). After fermenting OM, the dry cell weight of JW15 was 4.89 g/l, which was comparable to the predicted value (4.77 g/l), and 1.67 times higher than that of the MRS medium (3.02 g/l). Correspondingly, JW15 showed a rapid and increased production of lactic and acetic acid in the OM. To perform a scale-up validation, batch fermentation was executed in a 5-l bioreactor at 37℃ with or without a pH control at 6.0 ± 0.1. The biomass production of JW15 significantly improved (1.98 times higher) under the pH control, and the cost of OM was reduced by two-thirds compared to that in the MRS medium. In conclusion, OM may be utilized for mass producing JW15 for industrial use.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.278-278
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• 2022

Recently, the yield potential of high yield Tongil-type rice varieties has greatly increased, reaching 817kg/10a(Geumgang No.1). Moreover, in order to promote rice consumption and strengthen the competitiveness of the rice processing industry, the R&D of high yield Tongil-type rice varieties for each processing purpose, such as rice noodles, grain feed and industrial materials, has been continuously carried out. However, because Tongil-type rice varieties or lines are generally very vulnerable to cold damage, cold tolerance test can be said to be absolutely necessary to improve the cultivation safety. This study is the result of the seedling and field cold tolerance characteristic tests carried out in 2021 of high yield Tongil-type rice breeding lines. For the cold tolerance characteristic test of seedlings, total 303 high yield rice breeding lines for processing were treated in cold water of 13℃ and irrigation depth of 4cm for 10 days from the third-leaf age, then it was evaluated by comparing the degree of discoloration and withering with the checked varieties(Boramchan, Hanahreum No.2). Also, for the test of field, total 186 high yield rice breeding lines for processing were treated in cold water of 17℃ by keeping pouring day and night from 30 days after transplanting to ripening stage, then it was evaluated by comparing the degree of discoloration, delay of heading, shortening rate of stem length and percent of fertile grain etc. with the checked varieties. And the cold tolerance evaluative criteria were classified as strong(1~3), medium(4~6) and weak(7~9) in overall cold tolerance. (Seedling test) As for the degree of cold tolerance of the check variety, 'Boramchan' and 'Hanahreum No.2' showed a response of 'medium' and 'weak', respectively. However, there was no 'strong' line in the high yield rice breeding lines, 2 lines showed a 'medium' response, and 301 lines showed a 'weak' response. Therefore, except for a few lines(0.7%), most lines(99.3%) showed a 'weak' response. (Field test) In terms of the overall cold tolerance of the check variety, both 'Boramchan' and 'Hanahreum No.2' showed a 'medium' response. Similarly, there was no 'strong' line in the case of high yield rice breeding lines, 20 lines showed a 'medium' response, and 166 lines showed a 'weak' response. Therefore, except for some(10.8%) lines, most(89.2%) lines showed a 'weak' response. From the above results, we selected about 100 individuals with less seed shattering and degeneration of the ear tip, and with a relatively high percent of fertile grain, and are continuing to select lines with improved cold tolerance in the F4~F5 group in this year. As such, most of the Tongil-type rice varieties have poor cold tolerance and thus have low cultivation safety at low temperatures. However, it is important to select improved lines through generational progress because there are some lines that still have a certain level of cold tolerance among them.