• Journal of Hydrogen and New Energy
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• v.7 no.1
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• pp.81-92
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• 1996

The Ar/Ar-$H_2$ plasma method was applied to reduce oxides and refine metals of V, Ta and B. In addition, the high temperature chemical reaction in Ar plasma and of the refining reaction in the Ar-(20%)$H_2$ plasma were analyzed. The crude V of 96wt% purity was obtained at the ratio of $C/V_{2}O_{5}=4.50$ by the Ar plasma reduction grade and the maximum reduction was obtained at $C/V_{2}O_{5}=4.50$ due to the $O_{2}$ loss from the thermal decomposition of vanadium oxide. In the Ar-(20%)$H_2$ plasma refining, the metallic V of 99.2wt% was produced at the ratio of $C/V_{2}O_{5}=4.40$. It was considered that a main refining reaction resulted from the chemical reaction between the residual carbon and residual oxygen. The metallic Ta of 99.8wt% was obtained at the ratio of $C/Ta_{2}O_{5}=5.10$ in a Ar plasma reduction and the Oz loss from the thermal decomposition of tantalum pentoxide did not take place. The deoxidation reaction was more significant than the decarburization reaction in the Ar-(20%)$H_2$ plasma refining and the metallic Ta of 99.9wt% was produced within the range of $C/Ta_{2}O_{5}$ ratio of 4.50 to 5.10. The Vickers hardness of Ta in the above mentioned range was about 220Hv due to the decrease in a residual oxygen by the deoxidation reaction. On the other hand, C is no suitable agent for the reduction of $B_{2}O_{3}$ by the Ar and Ar-$H_2$ plasma. But Fe-B-Si alloy was produced with the reduction of $B_{2}O_{3}$ in the melt when Fe, C, $B_{2}O_{3}$, and ferroboron mixtures were melted by the high frequency induction melting.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.334-341
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• 2000

This study was conducted to determine the effects and optimum concentrantion of chemical mutagens, colchicine, EMS (ethyl methan sulfonate), MNU (1-methyl-3-1­-nitrosoguanidinenitro), sodium azide $(NaN_3)$ for induction of mutant plants. In order to induce the mutants of Dianthus superbus L, immature seed were pre-soaked in the warter adding each mutagens and concentration of EMS, colchicine, MNU, and sodium azide $(NaN_3)$. Comparision of morphological characteristic and seed germination in each mutant plants differed depending on mutagen sources and their concentrations. When 0.2% EMS were treated on seed, germination decreased to 12% while untreated control was germinated 76.6% for twenty days. Treatments of colchicine appeared higher germination than other mutagen but not survived. The survival rate was extremely decreased in MNU treatment at 0.5mM and chlorophyll-mutant plantlets were obtained by sodium azide treatment at 0.2mM. Chlorophyll mutants were produced by pre-soaking the immature seed of Dianthus superbus L. with mutagen, sodium azide. The control plants appeared normal green leaf color, while mutant plant after mutagenic treatment of immature seed results in yellow­-green stripes and albino in normal green leaf tissue. RAPD was carried out to check the genetic modification of regenerated plants by mutagen treatments at 0.2mM sodium azide. Three polymorphic DNA fragments out of thirty-seven obtained by RAPDs were observed in regenerated plants using five decamer primers.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.86-92
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• 2022

Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user's walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.243-248
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• 2022

As the scope of use of portable and wearable electronic devices is expanding, the limitations of heavy and bulky solid-state batteries are being revealed. Given that, it is urgent to develop a small energy harvesting device that can partially share the role of a battery and the utilization of energy sources that are thrown away in daily life is becoming more important. Contact electrification, which generates electricity based on the coupling of the triboelectric effect and electrical induction when the two material surfaces are in contact and separated, can effectively harvest the physical and mechanical energy sources existing in the surrounding environment without going through a complicated intermediate process. Recently, the interest in the harvest and utilization of wind energy is growing since the wind is an infinitely ecofriendly energy source among the various environmental energy sources that exist in human surroundings. In this study, the optimization of the energy harvesting device for the effective harvest of wind energy based on the contact electrification was analyzed and then, the utilization strategy to maximize the utilization of the generated electricity was investigated. Natural wind based Fluttering TENG (NF-TENG) using fluttering film was developed, and design optimization was conducted. Moreover, the safe high voltage generation system was developed and a plan for application in the field requiring high voltage was proposed by highlighting the unique characteristics of TENG that generates low current and high voltage. In this respect, the result of this study demonstrates that a portable energy harvesting device based on the contact electrification shows great potential as a strategy to harvest wind energy thrown away in daily life and use it widely in fields requiring high voltage.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.478-489
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• 2010

Penthiopyrad is a fungicide agent in types of pyrazole which is showing the effect of prevention in fungal disease and powdery mildew. In order to register this new pesticide, reports of acute toxicity and chronic toxicity by animal study were examined to set acceptable daily intake to evaluate hazards of consumers. Acute toxicity was low in toxic, and it did not have the effect of acute dermal toxicity, acute eye irritation, or skin sensitization. As the result of the study in chronic toxicity, the common effect of chemical appeared in the liver and thyroid which was proven as a toxic effect. Two-generation reproduction toxicity, genotoxicity, and prenatal development toxicity were not proven. As the result of carcinogenic study, increase of thyiroid follicular adenoma in the rat and the frequency of liver hepatocellar adenoma in mice were also increased. However, it was decided that the threshold value on the effect in chemicals could be controlled through study liver enzyme induction. Therefore, the ADI for penthiopyrad is 0.081 mg/kg/ bw/day, based on the NOAEL of 8.10 mg/kg bw/day of twelve-months dogs study and applying an uncertainty factor of 100.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.181-185
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• 2001

The naturally occurring chemical indole-3-carbinol (13C), found in vegetables of the Brassica genus, is a promising anticancer agent that was shown previ- ously to induce a Gl cell cycle arrest of human breast cancer cell lines, independent of estrogen receptor signaling. The anticancer activity of 13C and the possible mechanisms of its action were explored in a human hepatocellular carcinoma cell line, HepG2. Treatment of HepG2 cells with 13C suppressed the growth of the cells. The growth sup- pression caused by 13C ($IC_{50}$/: 444$\mu$M) was found to be partially due to its ability to stop the cell cycle in HepG2 cells. Western blot analysis for the Gl phase artiest demonstrated that the expression-levels of cyclin-dependent kinase (Cdk4, Cdk6) and cyclic D were reduced strongly after treatment of Hep72 cells with 13C (4007M) for 24- 72 hrs. Furthermore, I3C selectively abolished the expression of Cdk6 in a dose- and time-dependent manner, and accordingly, inhibited the phosphorylation of retinoblastoma. Interestingly, after the HepG2 cells reached their max- imal growth arrest, the level of the p21, a well-known Cdk inhibitor, increased significantly. Therefore, it could be considered that the Gl arrest of HepG2 cells treated with 13C was due to the indirect inhibition of Cdk4/6 activities by p21 Western blot analysis for G2/M phase arrest of demonstrated the levels of Cdc2 and cyclin Bl werer reduced dramatically after the treatment of HepG2 cells with 13C ($40\mu$M) for 24-72 hrs. flow cytometry of propidium iodide-stained HepG2 cells revealed that 13C induces a Gl (53%,72hr incubation) and G2 (25%,24hr incubation) cell cycle arrest. Thus, our observations have uncovered a previously undefined antiproliferative pathway for r3C that implicates Cdk4/6 and Cdc2 as a target for cell cycle control in human HepG2 cells. However, the 13C-medi- ated cell cycle arrest and repression of Cdk4/6 production did not affect the apoptotic induction of HepG2 cell.

• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.235-243
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• 2014

This research was conducted to investigate the influence of leaching fractions (LF) in each irrigation or fertigation on plant growth and changes in chemical properties of root media during the production of seedling grafts of tomato. Two root media containing Sphagnum peat moss plus vermiculite (5:5, v/v, PV) and coir dust plus vermiculite (5:5, v/v, CV) were formulated and pre-planting fertilizers were incorporated during formulation. Then, each medium was packed into 50 cell (volume 33 cc) and 105 cell (volume 18 cc) trays and the rootstock (cv. J3B Strong) and scion (cv. Sunmyung) were grown, respectively. The seedlings were grafted at 31 days after sowing and then the cut seedling grafts (Sunmyung scion/J3B Strong rootstock) were planted into 50 cell plug trays containing each of the two root media. After induction of the graft union and new adventitious roots for 7 days, the seedling grafts were fed with fertilizer solution once a week containing 4 different N concentrations (0, 50, 100, $200mg{\cdot}L^{-1}$). When determined after 31 days from seed sowing, the highest fresh weights of the root stock seedlings were obtained with 0.75 LF in PV (8.96g/seedling) and CV (7.11g/seedling) mixes. The EC of the both mixes were 0.93 and $1.09dS{\cdot}m^{-1}$, respectively. The fresh weights of the scion seedlings 31 days after seed sowing were 4.29g with 0.50 LF in the PV and 3.13g with 0.50 LF in the CV. The root medium ECs of the two treatments were 0.76 and $1.34dS{\cdot}m^{-1}$, respectively. Fresh weights of the seedling grafts grown for 31 days were greatly influenced by post-planting fertilizer concentrations. The heavier plants were obtained in $100mg{\cdot}L^{-1}$ N treatment than any other treatments in same mixes. The substrate ECs in these two treatments were 0.98 and $1.93dS{\cdot}m^{-1}$, respectively, indicating that the desirable range of soluble salts in soil extracts is higher in the CV mix than the PV mix. Results of this study suggest that optimum EC range is different in each medium and LF need to be adjusted differently for each root medium to produce high quality seedling grafts of tomato.

• KSBB Journal
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• v.21 no.3
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• pp.204-211
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• 2006

For the production of the recombinant human interferon-gamma(rhIFN-${\gamma}$) in Escherichia coli, human glucagon and ferritin heavy chain were used as fusion partners. Even though rhIFN-${\gamma}$ is expressed as an inclusion body form in E. coli because of strong hydrophobicity of itself, over 50% of fused rhIFN-${\gamma}$ was expressed as soluble form in E. coli $Origami^{TM}$(DE3) harboring pT7FH(HE)-IFN-${\gamma}$ which encodes ferritin heavy chain-fused rhIFN-${\gamma}$. In the case of using glucagon-ferritin heavy chain hybrid mutant as a fusion partner, 6X His-tag was additionally introduced to N-terminus of GFHM(HE)-IFN-${\gamma}$ for enhancing purification yields of rhIFN-${\gamma}$. Fusion protein HGFHM(HE)-IFN-${\gamma}$ with two 6X His-tag was more effectively bound to Ni-NTA agarose bead than GFHM(HE)-IFN-${\gamma}$ with a 6X His-tag. rhIFN-${\gamma}$ was completely purified from enterokinase-treated HGFHM(HE)-IFN-${\gamma}$ by Ni-NTA affinity column. For high-level production of rhIFN-${\gamma}$, glucose was used as the sole carbon source with simple exponential feeding rate($2.4{\sim}7.2g/h$) in fed-batch process. The effective lactose concentration for the expression of the rhIFN-${\gamma}$ was $10{\sim}20mM$. Under the fed-batch culture conditions, rhIFN-${\gamma}$ production yield reached 11 g DCW/L for 6 hours after lactose induction.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.407-416
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• 1996

The reactive intermediates formed during the metabolism of therapeutic agents, toxicants and carcinogens by cytochromes P450 are frequently capable of covalently binding to tissue macromolecules and causing tissue damage. It has been shown that YH439, a congener of malotilate, is effective in suppressing hepatic P450 2E1 expression. The present study was designed to further establish the mechanistic basis of YH439 protection against toxicant by assessing its effects against chemical-mediated potentiated hepatotoxicity. Retinoyl palmitate (Vit-A) pretreatment of rats for 7 days substantially enhanced carbon tetrachloride hepatotoxicity, as supported by an ${\sim}5-fold$ increase in serum alanine aminotransferase (ALT) activity, as compared to $CCl_4$ treatment alone. The elevation of ALT activity due to Vit-A was completely blocked by the treatment of $GdCl_3$ a selective inhibitor of Kupffer cell activity. Concomitant pretreatment of rats with both YH439 and Vit-A resulted in a 94% decrease in Vit-A-potentiated $CCl_4$ hepatotoxicity. YH439 was also effective against propyl sulfide-potentiated $CCl_4-induced$ hepatotoxicity. Whereas propyl sulfide (50 mg/kg, 7d) enhanced $CCl_4-induced$ hepatotoxicity by >5-fold, relative to $CCl_4$ treatment alone, concomitant treatment of animals with both propyl sulfide and YH439 at the doses of 100 and 200 mg/kg prevented propyl sulfide-potentiated $CCl_4$ hepatotoxicity by 35% and 90%, respectively. Allyl sulfide, a suppressant of hepatic P450 2E1 expression, completely blocked the propyl sulfide-enhanced hepatotoxicity, indicating that propyl sulfide potentiation of $CCl_4$ hepatotoxicity was highly associated with the expression of P450 2E1 and that YH439 blocked the propyl sulfide-enhanced hepatotoxicity through modulation of P450 2E1 levels. Propyl sulfide- and $CCl_4-induced$ stimulation of lipid peroxidation was also suppressed by YH439 in a dose-related manner, as supported by decreases in malonedialdehyde production. The role of P450 2E1 induction in the potentiation of $CCl_4$ toxicity and the effects of YH439 were further evaluated using pyridine as a P450 2E1 inducer. Pyridine pretreatment substantially enhanced the $CCl_4$ hepatotoicity by 23-fold, relative to $CCl_4$ alone. YH439, however, failed to reduce the pyridine-potentiated toxicity, suggesting that the other form(s) of cytochroms P450 inducible by pyridine, but not suppressible by YH439 treatment, may play a role in potentiating $CCl_4-induced$ hepatotoxicity. YH439 was capable of blocking cadmium chloride-induced liver toxicity in mice. These results demonstrated that YH439 efficiently blocks Vit-A-enhanced hepatotoxiciy through Kupffer cell inactivation and that the suppression of P450 2E1 expression by YH439 is highly associated with blocking of propyl sulfide-mediated hepatotoxicity.