• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.70-78
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• 2013

Rhizoctonia solani and Fusarium oxysporum cause yield losses in numerous economically important crops. To develop a bio-control agent, cell free extracellular compounds (ECs) of 5 bacterial strains Burkholdria sp. L1, Pseudomonas sp. L4, Pseudomonas chlororaphis VN391, Bacillus subtilis VN21 and Enterobacter sp. VN99 from Vietnamese fields, which reduced levels of R. solani root rot in lettuces and F. oxysporum root rot in tomatoes, were investigated. In a growth chamber, ECs of all antagonists markedly enhanced the biomass of lettuces (10 to 14.1%) and tomatoes (11.38 to 13.88%). In greenhouses, the disease's severity on both crops treated with ECs of the antagonists was reduced significantly and biomass losses in the plants decreased markedly. The reduction level of R. solani root rot in lettuces was 75, 66.7, 50, and 16.7% by ECs of strains L1, L4, VN21 and VN391, respectively. The biomass of lettuces increased markedly by 29.13%, 21.67%, and 23.4% by ECs of strains L1, L4 and VN21, respectively. Similarly, the reduction levels of F. oxysporum root rot in tomatoes was 76.3, 75, 41.7 and 25% by ECs of strain L1, L4, VN21 and VN391, respectively, and the biomass was significantly enhanced by 14.42, 12.7 and 13%, respectively. The ECs of strain L1 exhibited the most effective bio-control agents to suppress R. solani and F. oxysporum.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.429-437
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• 2015

It has been known that acetylation improves the dimensional stability of wood. Liquid phase acetylation is more popular than gas-phase acetylation for the effectiveness of weight gain of wood. In this study domestic red and Korean pine specimens were liquid phase acetylated and their physical properties, such as density, bending strength, dimensional stability etc., were investigated. Acetylation increased the average weights of red and Korean pine specimens by 10.4% and 9.2%, respectively, and their average oven-dry densities were increased by 6.9% and 4.6%, respectively. Acetylation did not influence on modulus of rupture (MOR), modulus of elasticity (MOE) and dynamic MOE (DMOE). The average percentage reduction in hygroscopicity (PRH) of red and Korean pine specimens were respectively 20.6% and 13.8%, while the average percentage reduction in water soaking (PRW) were respectively 20.0% and 8.5%. Thus it can be concluded that the liquid acetylation improved the dimensional stability of red pine specimens more than that of Korean pine specimens.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.84-90
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• 2006

This study was conducted to anticipate nitrate reduction state in tree through measurement of nitrate reductase activity (NRA) and investigate the effect of nitrogen concentrations (100, 200, 400, and 600 $mg\;L^{-1}$) on growth, the nitrogen content of various tissue, and NRA of pear (Pyrus pyrifolia cv. Niitaka) seedlings in sand culture. Nutrient solutions used in this experiment were adjusted to pH 6.5 and fixed the ratio of ammonium and nitrate to 1:3 and trickle-irrigated 3 times a day. Tree height and dry weight of various organs in seedlings were higher in low nitrogen concentration (100 and 200 $mg\;L^{-1}$) than in high nitrogen concentration (400 and 600 $mg\;L^{-1}$). The shoot growth in 600 $mg\;L^{-1}$ was extremely poor by nitrogen over supply. Increasing the nitrogen concentration, the concentration of nitrate-N in leaves and roots were insignificantly changed but that of stems increased. The accumulation of total and reduced nitrogen in all organs with increasing concentrations of nitrogen supply were increased at 30 days after treatment but those of all organs at 60 and 90 days after treatment were highest in 600 $mg\;L^{-1}$, whereas there were no significant changes among other nitrogen concentration. The in vivo (${+NO_3}^-$) NRA of all organs did not relate to nitrogen concentration but the in vivo (${-NO_3}^-$) NRA of leaves except roots increased with increasing the nitrogen concentration. Therefore, the proper nitrogen concentration to promote growth and nitrate reduction of pear tree was 200 $mg\;L^{-1}$.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.940-945
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• 2007

We have examined the induction of HL-60 cell differentiation by treatment of 2-chloromethyl-1-dihydroxyphosphinyl pyrrolidine(2C-1DPP), which is derivative of piperidine and pyrrolidine by ${\alpha}-phosphoramidoakylation$ reaction. It was observed that HL-60 cell proliferation was dose- and time-dependently inhibited by treatment with 2C-1DPP. 2C-1DPP treatment caused a significant change in NBT reduction and enhanced ATRA-induced NBT reduction. Treatment of 2C-1DPP to HL-60 cells increased only CD11b expression in the cells, and also increased markedly G0/G1 stage arrest of HL-60 cells. These results can suggest that 2C-1DPP induced the differentiation of HL-60 cells to granulocytes lineage and enhanced ATRA-induced differentiation. Moreover, DNA expression levels of p27 were up-regulated during 2C-1DPP-dependent HL-60 cell differentiation. Our results suggest that 2C-1DPP have potential as a therapeutic agent in human leukemia.

• Journal of Environmental Science International
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• v.30 no.2
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• pp.135-143
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• 2021

This study executed evaluation of drying characteristics based on the polymer injection rate (8%, 10% and 12%) and the drying method[NIF(near-infrared ray). According to this study analyzed VS, VS/TS, and calorific value compared with 'the auxiliary fuel standard of the thermoelectric power plant and the combined heat & power plant'. The results are as follows. In the case of NIR, the VS was slightly changed at the early stage of the material preheating period and the constant drying rate period with low moisture evaporation. But VS reduction was shown higher as moisture was dried. In the case of non-digested sludge with high VS content, the VS reduction rate by drying was shown lower than that of digested sludge. As the flocculant injection rate increased, the VS loss due th drying was found to be small. Also, the higher the flocculant injection rate was the longer the drying time. Especially, in the case of the NIR drying equipment, as the moisture content of sewage sludge decreased(moisture content 20~40%), the loss of net VS also showed a tendency to increase sharply. It is shown that the high calorific value according to the drying time of the non-digested sludge was changed from 590 kcaℓ/kg to 3,005 kcaℓ/kg and from 539 kcaℓ/kg to 2,796 kcaℓ/kg.

• Journal of IKEEE
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• v.24 no.4
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• pp.1058-1063
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• 2020

This paper proposes a 12-bit SAR A/D(Successive Approximation Register Analog-to-Digital) converter that operates at low power for bio-signal and sensor signal processing. The conventional SAR A/D converter utilized the reduction of the dynamic current, which resulted in reducing total power consumption. In order to solve the limitation of the sampling time due to charging/discharging of the capacitor for reducing dynamic current, the different sampling time on the C-DAC bit switch operation was applied to reduce the dynamic current. In addition, lowering the supply voltage of the digital block to 0.6V led to 70% reduction of the total power consumption of the proposed ADC. The proposed SAR A/D was implemented with CMOS 65nm process 1-poly 6-metal, operates with a supply voltage of 1.2V. The simulation results demonstrate that ENOB, DNL/INL, power consumption and FoM are 10.4 bits, ±0.5LSB./±1.2LSB, 31.2uW and 2.8fJ/step, respectively.

• BMB Reports
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• v.55 no.2
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• pp.92-97
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• 2022

Lysine methylation is one of the most important histone modifications that modulate chromatin structure. In the present study, the roles of the histone lysine demethylases JMJD2a and LSD1 in CK2 downregulation-mediated senescence were investigated. The ectopic expression of JMJD2a and LSD1 suppressed the induction of senescence-associated β-galactosidase activity and heterochromatin foci formation as well as the reduction of colony-forming and cell migration ability mediated by CK2 knockdown. CK2 downregulation inhibited JMJD2a and LSD1 expression by activating the mammalian target of rapamycin (mTOR)-ribosomal p70 S6 kinase (p70S6K) pathway. In addition, the down-regulation of JMJD2a and LSD1 was involved in activating the p53-p21^Cip1/WAF1-SUV39h1-trimethylation of the histone H3 Lys9 (H3K9me3) pathway in CK2-downregulated cells. Further, CK2 downregulation-mediated JMJD2a and LSD1 reduction was found to stimulate the dimethylation of Lys370 on p53 (p53K370me2) and nuclear import of SUV39h1. Therefore, this study indicated that CK2 downregulation reduces JMJD2a and LSD1 expression by activating mTOR, resulting in H3K9me3 induction by increasing the p53K370me2-dependent nuclear import of SUV39h1. These results suggest that CK2 is a potential therapeutic target for age-related diseases.

• Journal of the Korean Applied Science and Technology
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• v.38 no.2
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• pp.618-627
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• 2021

Functional cosmetics are products that help emphasize certain functions such as skin whitening, wrinkle reduction and UV protection. Functional cosmetic items have expanded since 2017. Korea's functional cosmetics industry has focused on skin whitening, wrinkle reduction, UV protection, and high-performance items including medical cosmetics that are in the research and development stage. France leads the international export performance rankings followed by the United states and Germany. France's cosmetic industry is renowned for emphasizing mechanism driven functional cosmetics in bio-industrial and functional materials, while the United states cosmetic industry is in high demand for luxury premium products. The German cosmetic industry is showing growing strength in bio high tech functional cosmetics. For the Korean cosmetic industry to challenge the top 3, it will also have to develop new material of various functional cosmetics that can be applied to emerging industries, and develop a variety of industry equipment in an environment where politics and economy are backed by more focus on research.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.222.1-222.1
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• 2015

Recently, graphene quantum dots (GQDs) have attracted great attention due to various properties including cost-effectiveness of synthesis, low toxicity, and high photostability. Nevertheless, the origins of photoluminescence (PL) from GQDs are unclear because of extrinsic states of the impurities, disorder structures, and oxygen-functional groups. Therefore, to utilize GQDs in various applications, their optical properties generated from the extrinsic states should be understood. In this work, we have focused on the effect of oxygen-functional groups in PL of the GQDs. The GQDs with nanoscale and single layer are synthesized by employing graphite nanoparticles (GNPs) with 4 nm. The series of GQDs with different amount of oxygen-functional groups were prepared by the chain of chemical oxidation and reduction process. The fabrication of a series of graphene oxide QDs (GOQDs) with different amounts of oxygen-contents is first reported by a direct oxidation route of GNPs. In addition, for preparing a series of reduced GOQDs (rGOQDs), we employed the conventional chemical reduction to GOQDs solution and controlled the amount of reduction agents. The GOQDs and rGOQDs showed irreversible PL properties even though both routes have similar amount of oxyen-functional groups. In the case of a series of GOQDs, the PL spectrum was clearly redshifted into blue and green-yellowish color. On the other hand, the PL spectrum of rGOQDs did not change significantly. By various optical measurement such as the PL excitation, UV-vis absorbance, and time-resolved PL, we could verify that their PL mechanisms of GOQDs and rGOQDs are closely associated with different atomic structures formed by chemical oxidation and reduction. Our study provides an important insights for understanding the optical properties of GQDs affected by oxygen-functional groups. [1]

• New & Renewable Energy
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• v.19 no.4
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• pp.20-26
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• 2023

Emitted CO₂ is an attractive material for microbial electrochemical CO₂ reduction. Microbial electrochemical CO₂ reduction (i.e., microbial electrosynthesis, MES) using biocatalysts has advantages compared to conventional CO₂ reduction using electrocatalysts. However, MES has several challenges, including electrode performance, biocatalysts, and reactor optimization. In this study, an MES system was investigated for optimizing reactor types, counter electrode materials, and CO₂-converting microorganisms to achieve effective CO₂ upcycling. In autotrophic cultivation (supplementation of CO₂ and H₂), CO₂ consumption of Rhodobacter sphaeroides was observed to be four times higher than that with heterotrophic cultivation (supplementation of succinic acid). The bacterial growth in an MES reactor with a single-chambered shape was two times higher than that with a double chamber (H-type MES reactor). Moreover, a single-chambered MES reactor equipped with titanium mesh as the counter electrode (anode) showed markedly increased current density in the graphite felt as a working electrode (cathode) compared to that with a graphite felt counter electrode (anode). These results demonstrate that the optimized conditions of a single chamber and titanium mesh for the counter electrode have a positive effect on microbial electrochemical CO₂ reduction.