• Korean Journal of Materials Research
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• v.14 no.9
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• pp.627-633
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• 2004

Lithium titanate whiske($Li_{x}Ti_{4}O_9$) was prepared by an ion-exchange reaction. To this end, the initial material, potassium tetratitanate ($K_{2}Ti_{4}O_9{\cdot}nH_{2}O$) was prepared by calcination of a mixture of $K_{2}CO_3\;and\;TiO_2$ with a molar ratio of 2.8 at $1050^{\circ}C$ for 3 h, followed by boiling water treatment of the calcined products for 10 h. Fibrous potassium tetratitanate could be transformed into layered hydrous titanium dioxide ($H_{2}Ti_{4}O_9{\cdot}nH_{2}O$) through an exchange of $K^{+}\;with\;H^{+}$ using 0.075 M HCl. Also, lithium titanate whisker was finally prepared as $Li^{+}\;and\;H^{+}$ ions were exchanged by adding 20 mL of a mixture solution of LiOH and $LiNO_3$ to 1g whisker and stirring for $5\~15$ days. The average length and diameter of the $Li_{x}Ti_{4}O_9$ whiskers were $10\~20{\mu}m\;and\;1\~3{\mu}m$, respectively.

• Journal of the Korean Society of Fashion and Beauty
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• v.4 no.4 s.10
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• pp.81-86
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• 2006

Numerous novel ingredients have been introduced for the hight functionality of whitening cosmetics. Tough the preliminary research, we have found water extracts Bombyx mori have high whitening efficacy. The results of the research for the whitening effect of Bombyx Mori L. are as follow 1. Bombyx Mori L. inhibited concentration dependently the generation of melanin increased by the stimulation of $\alpha$-MSH and protoporphyrin IX, and $IC_{50}$ value was 8.3, 9.2 ${\mu}M$ respectively. 2. Melanin increased by the stimulation of $\alpha$-MSH and protoporphyrin IX was five to seven times superior in the inhibiting effect, compared with kojic acid used as positive control group. 3. Bombyx Mori L. did not have a decolorizing effect on melanin already generated. 3. Bombyx Mori L. was observed to have toxicity of over 100 ${\mu}M$ for the mouse melanoma B16 cells. Therefore, These results suggest that water extracts of Bombyx mori have inhibitory activity against mushroom tyrosinase and inhibitory activity of melanin synthesis in B16 melanoma cells in vitro.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.549-554
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• 2009

Al thin films were synthesized on TiN/Si substrate by MOCVD using N-methylpyrrolidine alane (MPA) precursor. Effects of substrate temperature, reaction pressure on the deposition rate, surface roughness and electrical resistivity were investigated. The early stage of Al thin film formation was analyzed by in-situ surface reflectivity measurement with a laser and photometer apparatus. From the Arrhenius plot of deposition rate vs. substrate temperature, it was found that the activation energy of surface reaction was 91.1kJ/mole, and the transition temperature from surface-reaction-limited region to mass-transfer-limited region was about $150^{\circ}C$. The growth rate increased with the reaction pressure, and average growth rates of $200{\sim}1,200nm/min$ were observed at various experimental conditions. Surface roughness of the film increased with the film thickness. The electrical resistivity of Al film was about $4{\mu}{\Omega}{\cdot}cm$ in the case of optimum condition, and it was close to the value of the bulk Al, $2.7{\mu}{\Omega}{\cdot}cm$.

• BMB Reports
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• v.34 no.3
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• pp.244-249
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• 2001

The anabolic acetolactate synthase III was purified to homogeneity from Serratia marcescens using DEAE-Sepharose, Phenyl-Sepharose, and hydroxylapatite column chromatography The native molecular weight of the enzyme was approximately 165 kDa. The enzyme is composed of two large and two small subunits with molecular weights of 64 and 15 kDa, respectively. The N-terminal sequence of the large and small subunit of the enzyme was Ser-Ala-Thr-Pro-Gln-Pro-Ser-Thr-Arg-Phe-Thr-Cys-Ala-Gln-Leu-Ile-Ala-His-Leu and Met-Leu-Gln-Pro-Gln-Asp-Lys-Pro-Gln-Val-Ile-Leu-Glu-Leu-Ala-Val-Arg-Asn-His-Pro-Gly-Val-Met-Ser-His-Val, respectively. The optimum pH and pI value were 7.5 and 5.5, respectively The $IC_{50}$ values were $20\;{\mu}M$ and $14\;{\mu}M$ for valine and herbicide SU7, respectively. The substrate specificity ratio, R value, was determined to be approximately 40, which suggests that this enzyme prefers the formation of $\alpha$-aceto-$\alpha$-hydroxybutyrate leading to the synthesis of isoleucine.

• BMB Reports
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• v.48 no.2
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• pp.121-126
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• 2015

Here we report a new chemical inhibitor against HIV-1 with a novel structure and mode of action. The inhibitor, designated as A1836, inhibited HIV-1 replication and virus production with a 50% inhibitory concentration ($IC_{50}$) of $2.0{\mu}M$ in an MT-4 cell-based and cytopathic protection antiviral assay, while its 50% cytotoxic concentration ($CC_{50}$) was much higher than $50{\mu}M$. Examination of the effect of A1836 on in vitro HIV-1 reverse transcriptase (RT) and integrase showed that neither were molecular targets of A1836. The characterization and re-infection assay of the HIV-1 virions generated in the presence of A1836 showed that the synthesis of early RT products in the cells infected with the virions was inhibited dose-dependently, due in part to abnormal protein formation within the virions, thus resulting in an impaired infectivity. These results suggest that A1836 might be a novel candidate for the development of a new type of HIV-1 inhibitor.

• Toxicological Research
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• v.23 no.2
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• pp.127-133
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• 2007

Metformin is a drug used to lower blood sugar levels in patients with type 2 diabetes via activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK). The primary objective of this study was to investigate whether metformin at the pharmacologically effective concentrations affects the expressions of ${\gamma}$-glutamylcysteine synthetase and phase II antioxidant genes in the H4IIE cell. Treatment of the cells with either metformin or 5-aminoimidazole-4-carboxamide riboside (AICAR) abrogated tert-butylhydroxyquinone (t-BHQ) induction of ${\gamma}$-glutamylcysteine synthetase, a rate limiting enzyme of GSH synthesis. The ability of t-BHQ to induce glutathione S-transferases (GSTs), a major class of phase II detoxifying enzymes that playa critical role in protecting cells from oxidative stress or electrophiles, was also inhibited by the agents. Transcriptional gene repression by metformin was verified by the GSTA2 promoter luciferase assay. Moreover, either metformin or AICAR treatment significantly decreased t-BHQ-dependent induction of other GSTs (i.e., $GST{\mu}$ and $GST{\pi}$ forms). Taken together, our data indicate that metformin treatment may result in the repression of ${\gamma}$-glutamylcysteine synthetase and glutathione S-transferase genes possibly via AMPK activation.

• Journal of the Korean Graphic Arts Communication Society
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• v.21 no.2
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• pp.101-108
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• 2003

We synthesised 1,3-Diphenyl-5-pyren-2-yl-4,5-dihydro-1H-pyrazole(DPP) and investigated its optical properties. The structure of DPP was confirmed by GC-Mass and elemental analysis. The absorption and photoluminescent spectra of DPP were measured at both hydrophobic and hydrophilic solvents and by the stokes shifts of DPP Lippert's equation could be applied. The results showed linear relation between $[{\varepsilon}-1/2{\varepsilon}+1)-(n^2-1/2n^2+1)]$ and $({\mu}_g\;-\;{\mu}_2)^2$.

• The Journal of Korean Medicine
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• v.24 no.4
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• pp.43-53
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• 2003

Drynariae Rhizorna (DR), an herbal medicine known for its effect to purify blood quality and improve circulation, frequently appears as the main ingredient in prescriptions for bone injuries. Currently, how pharmacologically it contributes to the reformation of bone is unclear. In the present study, the effect of the aqueous extract of DR on bone cells was investigated in vitro for the first time. The human osteoprecursor cells (OPC-I) were incubated in the medium with different concentrations of the aqueous extract of DR and the cell proliferation was studied. When the concentration of DR aqueous extract was $<120{\;}\mu\textrm{g}/ml$, the proliferation of OPC-I was enhanced. However, the proliferation of OPC-I was inhibited by DR extract with the concentrations $>250{\;}\mu\textrm{g}/ml$. Under most treatments, the cells presented very pale expression for cyclooxygenase-2 (Cox 2) protein; a slightly intensified band showed at the highest DR concentration, 1.0 mg/ml during the course of culture. From the results, it was concluded that the aqueous extract of DR was found to directly stimulate the proliferation, alkaline phosphatase (ALP) activity, protein secretion and particularly type I collagen synthesis of OPC-I at dose-dependent manner.

• Journal of Powder Materials
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• v.22 no.5
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• pp.331-336
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• 2015

We report on the succesful fabrication of ZnO nanorod (NR)-based robust piezoelectric nanogenerators (PNGs) by using Cu foil substrate. The ZnO NRs are successfully grown on the Cu foil substrate by using all solution based method, a two step hydrothermal synthesis. The ZnO NRs are grown along c-axis well with an average diameter of 75~80 nm and length of $1{\sim}1.5{\mu}m$. The ZnO NRs showed abnormal photoluminescence specrta which is attributed from surface plasmon resonance assistant enhancement at specific wavelength. The PNGs on the SUS substrates show typical piezoelectric output performance which showing a frequency dependent voltage enhancement and polarity dependent charging and discharging characteristics. The output voltage range is 0.79~2.28 V with variation of input strain frequency of 1.8~3.9 Hz. The PNG on Cu foil shows reliable output performance even at the operation over 200 times without showing degradation of output voltage. The current output from the PNG is $0.7{\mu}A/cm^2$ which is a typical out-put range from the ZnO NR-based PNGs. These performance enhancement is attributed from the high flexibility, high electrical conductivity and excellent heat dissipation properties of the Cu foil as a substrate.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.1
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• pp.111-119
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• 1994

"Spontaneous" hardening of the zona pellucida of mouse oocytes during in vitro culture is most likely due to cortical granules exocytosis. Thus the purpose of the present study was to determine whether the exocytosis factor is involved in spontaneous zona pellucida hardening during in vitro culture of the mouse. The results obtained form these experiments were summarized as follows; 1. When a protein synthesis inhibitor(100${\mu}g$/ml puromycin) was added to the culture medium, it did not prevent spontaneous ZPH of mouse oocyte during in vitro culture. 2. Calmodulin antagonists (trifluoperazine and chlorpromazine) and calcium channel blocker (verapamil) had no inhibitory effect in spontaneous ZPH. 3. A microtubule assembly inhibitor, colcemid had some inhibitory effect on spontaneous ZPH. 4. Treatment with a microfillament formation blocker(cytochalasin-B) at 1${\mu}g$/ml concentration, resulted in the excellent inhibitory effect on spontaneous ZPH. However cytochalasin-B did not inhibit ethanol-induced ZPH.