• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.293-294
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• 1998

In this paper, the electric properties of amorphous selenium specimen has been investigated. Amorphous selenium was thermally evaporated on the glass plate which had been deposited onto the interface by aluminium as an electrode. On the surface of the amorphous selenium, the aluminium electrode was deposited again in order to make an unit cell for dark current measurement. The dark current was measured while applying the bias voltage across the selenium layer in the range of 0V-2500 Volts. The leakage property of the amorphous selenium was significantly low at even high voltage range so it has good advantage as a X-ray receptor for digital radiography. For further study, the C-V curves measurement according to thicker amorphous selenium layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.151-154
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• 1998

The layered trivanadate, LiV$_3$O$_{8}$ has been investigated as a cathode material for secondary lithium batteries. Early in its development the preparation method of LiV$_3$O$_{8}$ strongly influenced its electrochemical properties, such as discharge capacity, rate capability and cycling efficiency. In the present experiment, a new synthesis route has been applied to obtain LiV$_3$O$_{8}$ . Instead of the conventional high temperature technique leading to the crystalline form, a solution technique producing the amorphous form has been used. This material, after dehydration, shows an electrochemical performance exeeding that of the crystalline one. The rationale for this behavior mainly lies in microscopic factors, i.e., in the possibility for the unit cell of amorphous LiV$_3$O$_{8}$ to insert up to 9 Li$^{+}$, instead of six for crystalline LiV$_3$O$_{8}$ . The ultrasonically treated products in water were characterized by XRD, TGA, DSC, and SEM. These measurements showed that the ultrasonic treatment process of crystalline LiV$_3$O$_{8}$ causes a decrease in crystallinity and considerable increases in specific surface area and interlayer spacing.g.

• BMB Reports
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• 제47권12호
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• pp.691-696
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• 2014

${\alpha}$-Enolase is a glycolytic enzyme and a surface receptor for plasminogen. ${\alpha}$-Enolase-bound plasminogen promotes tumor cell invasion and cancer metastasis by activating plasmin and consequently degrading the extracellular matrix degradation. Therefore, ${\alpha}$-enolase and plasminogen are novel targets for cancer therapy. We found that the amino acid sequence of a peptide purified from enzymatic hydrolysates of seahorse has striking similarities to that of ${\alpha}$-enolase. In this study, we report that this peptide competes with cellular ${\alpha}$-enolase for plasminogen binding and suppresses urokinase plasminogen activator (uPA)-mediated activation of plasminogen, which results in decreased invasive migration of HT1080 fibrosarcoma cells. In addition, the peptide treatment decreased the expression levels of uPA compared to that of untreated controls. These results provide new insight into the mechanism by which the seahorse-derived peptide suppresses invasive properties of human cancer cells. Our findings suggest that this peptide could emerge as a potential therapeutic agent for cancer.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1397-1400
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• 2013

The influence of electron beam irradiation on photocatalytic activity of $TiO_2$ thin films was investigated. $TiO_2$ thin films were prepared by anodization of Ti foil, and they were then subjected to an 1 MeV electron beam. Changes in physical properties and photocatalytic activity of $TiO_2$ before and after e-beam irradiation were investigated. The crystallinity of the synthesized materials was investigated by X-ray diffraction, and the oxidation states of both titanium and oxygen were determined by X-ray photoelectron spectroscopy (XPS). The density of donor ($N_d$) and flat band potential ($E_{fb}$) were investigated by Mott-Schottky analysis, and photocurrent was measured under a 1kW Xenon lamp illumination. After e-beam irradiation, significant change of Ti oxidation state was observed. $Ti^{3+}/Ti^{4+}$ ratio increased mainly due to the surface reduction by electron, and photocurrent was observed to increase with e-beam irradiation.

• Archives of Pharmacal Research
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• 제18권3호
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• pp.169-172
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• 1995

The changes in blood pressure may relate to the alterations of the responsiveness to vasoconstrictors and vasodilators, and these alterations can arise the modifications in the properties of angiotensin II (AII) receptor. In order to examine the changes of AII receptor in the hypertensive mechanism of renin-dependent hypertensive rats (RHRs; two-kidney, one-ligated type), we compared the equilibrium binding characteristics of $[^3H]$All in adrenal cortex and medulla from RHRs and normotensive rats. The dissociation constants of AII binding in both tissues of RHRs were very similar to those in the respective tissue of normotensive rats. However, the maximum binding was increased from 805 to 1050 fmole/mg protein in the adrenal cortex of RHRs, and decreased from 172 to 126 fmole/mg protein in the adrenal medulla of RHRs. These results imply that the up- and down-regulation of the All receptor population on the cell surface of adrenal glands from RHRs are consorted with the elevation of blood pressure and the activation of renin-angiotensin system.

• Journal of Microbiology and Biotechnology
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• 제16권10호
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• pp.1597-1604
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• 2006

To screen for an anti-yeast substance (AYS), many bacteria were isolated from soil and a strain AY2000 was selected. The strain AY2000 was identified as Rahnella aquatilis by morphology, biochemical properties, and 16S r-RNA nucleotide sequence analyses. The strain AY2000 showed anti-yeast activity against Candida albicans and Saccharomyces cerevisiae, whereas R. aquatilis ATCC33071 as a type strain did not show the activity against the yeasts under the same condition. The growth of yeast cell was significantly inhibited by AYS produced by the strain AY2000, as shown by optical density and MTT assay. The minimum inhibitory concentration (MIC) of the AYS against S. cerevisiae and C. albicans at $28^{\circ}C\;was\;20{\mu}g/ml\;and\;60{\mu}g/ml$, respectively. The MIC of AYS against hyphae of C. albicans at $37^{\circ}C\;was\;600{\mu}g/ml$. Scanning electron microscopic analysis revealed that yeast cells treated with AYS had an irregular form with a wrinkled and rough surface.

• 한국전기전자재료학회논문지
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• 제33권6호
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• pp.460-464
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• 2020

This study reports the fabrication and application of semitransparent Cu nanoparticle layers. Spin coating and subsequent drying of a Cu colloid solution were performed to deposit Cu nanoparticle layers onto Si and glass substrates. As the spin speed of the spin coating increases, the density of the nanoparticles on the substrate decreases, and the agglomeration of nanoparticles is suppressed. This microstructural variation affects the optical properties of the nanoparticle layers. The transmittance and reflectance of the Cu nanoparticle layers increase with increasing spin speed, which results from the trade-off between the exposed substrate area and surface coverage of the Cu nanoparticles. Since the glass substrates coated with Cu nanoparticle layers are semitransparent and colored, it is anticipated that the application of a Cu nanoparticle-dielectric bilayer structure to transparent solar cells will improve the cell efficiency as well as aesthetic appearance.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.419-425
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• 2001

A dense pellicular solid matrix has been fabricated by coating 4% agarose gel on to dense zironia-silica(ZS) spheres by watr-in-oil emulsification . The agarose evenly laminated the ZS bead to a depth of 30㎛, and the resultin gpellicular assembly was characterised by densities up to 2.39g/mL and a mean particle dimeter of 136 ㎛. In comparative fluidisation tests, the pellicular solid phase exhibited a two-fold greater flow velocity than commercial benchmark ad-sorbents necessary to achieve common values of bed expansion. Furthermore, the perlicular parti-cles were characterised by improved qualities of chromatographic behaviour, particularly with re-spect to a three-fold increase in the apparent effective diffusivity of lysozyme within a pellicular assembly modified with Cibacron Blue 3GA. The properties of rapid protein adsorption/desorp-tion were attributed to the physical design and pellicular deployment of the reactive surface in the solid phase. When combined with enhanced feedstock throughput, such practical advantages recommend the pellicular assembly as a base matrix for the selective recovery of protein products from complex, particulate feedstocks(whole fermentation broths, cell disruptates and biological extracts).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.231-235
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• 2005

Most tissue engineering strategies for creating functional replacement tissues or organs rely on the application of temporary three-dimensional scaffolds to guide the proliferation and spread of seeded cells in vitro and in vivo. Scaffolds should be satisfied following requirements; macrostructure to promote cell proliferation, pore interconnectivity, pore size ranging from 200 to $400{\mu}m$, surface chemistry and mechanical properties. Rapid prototyping techniques have often been used as an useful process that fabricates scaffolds with complex structures. In this study, a new process to fabricate a three-dimensional scaffolds using bio-compatible polymer has been developed. It employs a highly accurate three-dimensional positioning system with pressure-controlled syringe to deposit biopolymer structures. The pressure-activated microsyringe is equipped with fine-bore nozzles of various inner-diameters. In order to examine relationships between line width and process parameters such as nozzle height, applied pressure, and speed of needle, experiments were carried out. Based on the experimental results, three-dimensional scaffold was fabricated using the apparatus. It shows the validity of the proposed process.

• 대한금속재료학회지
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• 제50권2호
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• pp.183-190
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• 2012

Hydrogen was generated by the reaction of metal hydride with water. The variation of hydrogen generation with the kind of powders (milled $MgH_2$, and $MgH_2$ milled with various contents of MgO, $MgCl_2$ or $Ni+Nb_2O_5$) was investigated. $MgH_2$ powder with a hydrogen content of 6.05 wt% from Aldrich Company was used. Hydrogen is generated by the reaction of Mg as well as $MgH_2$ with water, resulting in the formation of byproduct $Mg(OH)_2$. For about 5 min of reaction time, milled $95%MgH_2+5%MgO$ has the highest hydrogen generation rate among milled $MgH_2+x%MgO$ (x=0, 5, 10, 15 and 20) samples. Milled $90%MgH_2+10%MgCl_2$ has the highest hydrogen generation rate among all the samples.