• Journal of Magnetics
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• v.1 no.2
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• pp.82-85
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• 1996

Magnetic properties and microstructures of melt spun misch metal-ferroboron alloys were investigated. The major phase is the tetragonal (rare earth)$_2Fe_{14}B$ phase. Magnetic properties showed coercivity of 5.6 kOe, remanence of 7.85 kG, and so energy product 8.9 MGOe. Microsturctures in optimum properties showed that matrix was composed of Ce-rich phase while second phase La-rich-oxygen phase with less amount of Fe element than matrix, and triple junction with La-rich phase contrary to matrix.

• Environmental Mutagens and Carcinogens
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• v.24 no.3
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• pp.128-136
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• 2004

CYP1A1 is known to be inducible by xenobiotic compouds such as polyciclic aromatic hydrocarbons(PAHs) and 2,3,7,8-tetrachloro-dibenzo-p-dioxin(TCDD). These chemicals have been identified worldwide and can have a significant impact on the human health and well being of human and wildlife. Given these issues, the detection and quantification of these chemicals in biological, environmental and food samples is important. First, we investigated the effect of on CYP1A1 promoter activity, 7-ethoxyresorufin-O-deethylase(EROD) activity and CYP1A1 mRNA expression induced by benzo(k)fluoranthene(B(k)F) in MCF-7 cells. We found that B(k)F significantly up-regulates the level of CYP1A1 prompter activity, EROD and CYP1A1 mRNA. When cells were treated with genistein, it was not changed that EROD and CYP1A1 mRNA, compared to that of control. However, genistein inhibited the B(k)F-induced CYP1A1 promoter activity and mRNA level at high concentration. Furthermore, in this study, effects of HDAC(histone deacetvlase) inhibitors on human prostate cancer cells proliferation were examined. HC-toxin, SAHA and TSA inhibited cell proliferation in PC3 cells. A novel HDAC inhibitor, IN2001 also suppressed the growth of PC3 cells. And IN2001 and SAHA increased S phase and G2/M phase at 12 hrs treatment but cells were arrested G0/G1 phase at 45 hrs treatment. The HC-toxin treatment for 24 hrs and 48 hrs increased G0/G1 at low concentration ($0.1\mu\textrm{m}$) but increased G2/M at more than concentration of $1\mu\textrm{m}$. TSA increased G2/M phase. These findings height the possbility of developing HDAC inhibitors as potential anticancer therapeutic agents for the treatment of prostate cancer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.117-120
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• 2000

The relation of crystal phase and charge/discharge capacity of $Li[Li_yMn_{2-y}]O_4$ were studied for different degrees of Li substitution (y). All cathode material showed spinel phase based on cubic phase in X-ray diffraction. Other peaks didn't show in spite of the increase of y value in $Li[Li_yMn_{2-y}]O_4$. Ununiform of $Li[Li_yMn_{2-y}]O_4$ which calcinated by (111) face and (222) face was more stable than that of pure $LiMn_2O_4$. In addition, At TG analysis, calcined $Li[Li_{0.1}Mn_{1.9}]O_4$ exhibited much mass loss at $800{\mu}m$. The cycle performance of the $Li(Li_yMn_{2-y}]O_4$ was improved by the substitution of $Li^{1+}$ for $Mn^{3+}$ in the octahedral sites. Specially, $Li[Li_{0.08}Mn_{1.92}]O_4$ and $Li[Li_{0.1}Mn_{1.9}]O_4$ cathode materials showed the charge and discharge capacity of about 125mAh/g at first cycle, and about 95mAh/g after 70th cycle. It is excellent than that of pure $LiMn_2O_4$, which 125mAh/g at first cycle, 65mAh/g at 70th.

• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.311-316
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• 1997

A high xylitol producing yeast was isolated from the sludge of xylose manufacturing factory and then identified as Candida tropicalis DS-72 according to physiological properties. The strain was able to produce xylitol in a high concentration up to 72g/l from 100g/l xylose in 32 hours. Medium optimization for xylitol production by C. tropicalis DS-72 was performed. Effect of various nitrogen sources on xylitol production was investigated. Of nitrogenous compounds, yeast extract was the most suitable organic nitrogen nutrient for the enhancement of xylitol production. However, inorganic nitrogen resulted in a low cell concentration and did not produce xylitol. Effect of inorganic salts such as KH$_{2}$PO$_{4}$, and MgSO$_{4}$, 7H$_{2}$O on xylitol production was also studied. Optimal medium was selected as xylose 100g/l, yeast extract 10g/l, KH$_{2}$PO$_{4}$, 5 g/l and MgSO$_{4}$, 7H$_{2}$O 0.2 g/l. Xylitol of 88 g/l was produced from 100 g/l xylose in 30 hours using the optimal medium in a flask. In a fermentor, a fed-batch culture with 300g/l xylose was carried out. A final xylitol concentration of 240 g/l in the culture could be obtained in 43 hours of culture time by maintaining the high level of dissolved oxygen during growth phase and limiting the dissolved oxygen in the same culture during production phase. This result corresponded to a xylitol yield of 80% and a xylitol productivity of 5.58 g/1-h.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.308-312
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• 2003

The objective of this paper is to investigate the power spectrum of a three-phase and a two-phase RCD (Random Pulse Centered Displacement) PWM scheme. The two-phase or three-phase pulses of RCD-PWM scheme are mutually center-aligned as in SVM(Space Vector Modulation), but the common pulse center is displaced randomly from the middle of the period. To verify the validity of the proposed two-phase RCD-PWM scheme, the power spectra of the output voltage, the d.c link current in the inverter drives and the radiated acoustic noise are experimentally investigated. And, the performance of the proposed two-phase RCD-PWM scheme was compared and discussed with the conventional three-phase RCD-PWM scheme.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.371-376
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• 2014

A novel three-phase hollow fiber liquid phase microextraction was developed for the determination of malachite green (MG) in environmental waters, which selected [BMIM][$PF_6$] mixed with 1% trioctylphosphine oxide (TOPO) as supported phase. Several parameters (accepter phase pH, sample pH, supported phase membrane, volume of accepter phase, salinity, extraction time) that could affect extraction performance were investigated. Under the optimal extraction conditions, the established approach showed excellent characters as: high enrichment factor (212), wide linear range ($0.20-100{\mu}gL^{-1}$), low detection limit ($0.01{\mu}gL^{-1}$), good reproducibility (RSD, 8.9%, n=5) and satisfactory recovery (84.0-106.2%). The method was applied to detect MG at Yangtze River and pond waters in Zhenjiang, Jiangsu province, and 4 sites among 15 sampling sites were found MG with the concentration of $1.73-11.06{\mu}gL^{-1}$, which confirmed that the proposed environmentally friendly method was simple and effective for monitoring MG in aquatic system.

• Journal of Microbiology
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• v.45 no.4
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• pp.318-325
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• 2007

Glucose 6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) in Deinococcus radiophilus, an extraordinarily UV-resistant bacterium, was investigated to gain insight into its resistance as it was shown to be involved in a scavenging system of superoxide $(O_2^{-1})$ and peroxide $(O_2^{-2})$ generated by UV and oxidative stresses. D. radiophilus possesses two G6PDH isoforms: G6PDH-1 and G6PDH-2, both showing dual coenzyme specificity for NAD and NADP. Both enzymes were detected throughout the growth phase; however, the substantial increase in G6PDH-1 observed at stationary phase or as the results of external oxidative stress indicates that this enzyme is inducible under stressful environmental conditions. The G6PDH-1 and G6PDH-2 were purified 122- and 44-fold (using NADP as cofactor), respectively. The purified G6PDH-1 and G6PDH-2 had the specific activity of 2,890 and 1,033 U/mg protein (using NADP as cofactor) and 3,078 and 1,076 U/mg protein (using NAD as cofactor), respectively. The isoforms also evidenced distinct structures; G6PDH-1 was a tetramer of 35 kDa subunits, whereas G6PDH-2 was a dimer of 60kDa subunits. The pIs of G6PDH-1 and G6PDH-2 were 6.4 and 5.7, respectively. Both G6PDH-1 and G6PDH-2 were inhibited by both ATP and oleic acid, but G6PDH-1 was found to be more susceptible to oleic acid than G6PDH-2. The profound inhibition of both enzymes by ${\beta}-naphthoquinone-4-sulfonic$ acid suggests the involvement of lysine at their active sites. $Cu^{2+}$ was a potent inhibitor to G6PDH-2, but a lesser degree to G6PDH-1. Both G6PDH-1 and G6PDH-2 showed an optimum activity at pH 8.0 and $30^{\circ}C$.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.734-745
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• 2016

This review article described the electrochemical Frumkin, Langmuir, and Temkin adsorption isotherms of over-potentially deposited hydrogen (OPD H) and deuterium (OPD D) for the cathodic $H_2$ and $D_2$ evolution reactions (HER, DER) at Pt, Ir, Pt-Ir alloy, Pd, Au, and Re/normal ($H_2O$) and heavy water ($D_2O$) solution interfaces. The Frumkin, Langmuir, and Temkin adsorption isotherms of intermediates (OPD H, OPD D, etc.) for sequential reactions (HER, DER, etc.) at electrode/solution interfaces are determined using the phase-shift method and correlation constants, which have been suggested and developed by Chun et al. The basic procedure of the phase-shift method, the Frumkin, Langmuir, and Temkin adsorption isotherms of OPD H and OPD D and related electrode kinetic and thermodynamic parameters, i.e., the fractional surface coverage ($0{\leq}{\theta}{\leq}1$) vs. potential (E) behavior (${\theta}$ vs. E), equilibrium constant (K), interaction parameter (g), standard Gibbs energy (${\Delta}G_{\theta}{^{\circ}}$) of adsorption, and rate (r) of change of ${\Delta}G_{\theta}{^{\circ}}$ with ${\theta}$ ($0{\leq}{\theta}{\leq}1$), at the interfaces are briefly interpreted and summarized. The phase-shift method and correlation constants are useful and effective techniques to determine the Frumkin, Langmuir, and Temkin adsorption isotherms and related electrode kinetic and thermodynamic parameters (${\theta}$ vs. E, K, g, ${\Delta}G_{\theta}{^{\circ}}$, r) at electrode/solution interfaces.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.47-53
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• 2015

Removal characteristics of Cu(II) ions by solid-phase extractant immobilized D2EHPA and TBP in PVC were investigated. Cu(II) ion concentrations in the solution and removal capacity of Cu(II) ion according to operation time were compared. The lower the initial concentration of Cu(II) ion in aqueous solution was, the removal capacity of Cu(II) ion by solid-phase extractant was increased relatively. The bigger the initial concentration of Cu(II) ion was, the removal capacity of Cu(II) ion was increased relatively. The pseudo-second-order kinetics according to operation time was showed more satisfying results than the pseudo-first-order kinetics for the removal velocity of Cu(II) ion. The removal capacity of Cu(II) ion was 0.025 mg/g in aqueous solution of pH 2, but the removal capacity of Cu(II) ion was increased to 0.33 mg/g mg/g in aqueous solution of pH 4 according to increasing pH.

• 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.