• Development and Reproduction
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• v.1 no.1
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• pp.25-28
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• 1997

The present study was conducted to determine the effect of recombinant human follicle stimulating hormone (rhFSH) on the estrogen synthesis by human fetal ovarian tissues. Fetal ovaries were 18-19 weeks old (18 wks:n=1, 19 wks:n=2). One case of 19-week-old fetal ovaries were obtained from anencephalic fetus. Obtained ovarieswere cleaned and diced around $600\mu\textrm{m}$ pieces, and cultured in the sandwich agar bed system for 21-23 days. Estrone ($E_{1}$) and estradiol-17 $\beta$($E_{2}$) in the medium was measured by radioimmunoassay. Amount of $E_{2}$ synthesis was greater than $E_{1}$ in both normal cases. In contrast, fetal ovaries from anencephalic fetus did not produce neither $E_{1}$ nor $E_{2}$ in the presence or absence of rhFSH. Results suggest that the fetal ovaries have a capacity of estrogen production at 18-19 weeks of gestation Existence of FSH receptor is also supposed. Different results by anecephalic fetal ovaries suggest the difference in the development between normal and anencephalic fetal ovaries.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.951-956
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• 2001

A 28-kDa extracellular lipase (pI 8.7) was purified to homogeneity from the culture supernatant of Trichosporon sp. Y- 11 by mmonium sulfate precipitation, DEAE-Sephadex A-50, Bio-Gel P-30, CM- Sephadex C-50, and Bio-Gel P- 10 chromatographies. The purified enzyme exhibited a specific activity of $2,741{\;}{\mu}mol/min/mg$ based on the hydrolysis of triolein, and the optimal hydrolysis activity was dentified at pH 8.0 and $40^{\circ}C$. The enzyme activity was inhibited by $Ag^+$ and enhanced by $Fe^{2+}$, $Fe^{3+}$, $Mg^{2+}$, $Mn^{2+}$, and $Li^{+}$. The enzyme activity exhibited for the hydrolysis of both tributyrin and trilinolein. The ester synthesis of unsaturated fatty acids with various alcohols catalyzed by the purified lipase in a nonaqueous medium or microaqueous system was also investigated. The esterification activity of the lipase increased with an increase of the carbon chain length in the alcohol. The synthesis rate of linoleic acid and oleyl alcohol was the highest with an optimal temperature and pH of $40^{\circ}C$ and 8.0, respectively. The water content and agitation also affected the esterification activity of the lipase.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.57-63
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• 2013

Ammonium dinitramide (AND) is one of the most promising oxidizers in propellants without chlorinated pollution to the atmosphere in these days. Potassium sulfamate (PS) is a key substance in ADN synthesis as forming nitrates such as $-N(NO_2)_2$. In this paper, potassium sulfamate as a starting material for ADN synthesis was prepared in a lab scale through crystallization with ethanol solvent, and observed the effects on the yield and purity of KDN. The prepared potassium sulfamates were analyzed using FE-SEM, XRD, BET and TGA-DSC. The lab-made PS, which was ground to $20{\mu}m$ showed more beneficial than a commercial product achieving high yield and purity of the synthesized KDN. It would be associated closely with crystallinity, porosity and pore size of prepared PS.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.109-117
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• 2004

The purpose of the present study was to examine the effect of diesel exhaust particles on human aortic vascular smooth muscle cells (VSMCs). DNA synthesis, cell viability and morphology of VSMCs after treatment of diesel exhaust particles (DEP) and fine particulate matter (PM$_{2.5}$) were assayed. PM$_{2.5}$ inhibited the DNA synthesis of VSMCs in a concentration -dependent manner, whereat DEP did not affect VSMCs up to 50$\mu\textrm{g}$/mL. These results were confirmed by morphological examination of VSMCs. PM$_{2.5}$ showed a dose-dependent cytotoxicity of VSMCs by MTT assay. Fraction 4 (organic acids) and fraction 8 (moderately polar compounds) showed the most potent inhibition of DNA synthesis of VSMCs, and fraction 7 (slightly polar compounds), fraction 9 (higher polar compounds), and fraction 6 (aromatic compounds) were next order. These results were confirmed by morphological examination of VSMCs. These results suggest that PM$_{2.5}$ inhibits the DNA synthesis of VSMCs through the cytotoxicity.oxicity.

• Journal of Powder Materials
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• v.12 no.1
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• pp.17-23
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• 2005

Dense $WSi_2$-20vol.%SiC composite was synthesized by high-frequency induction-heated combustion synthesis(HFIHCS) method within 2 minutes in one step from elemental powder mixture of W, Si and C. Simultaneous combustion synthesis and densification were accomplished under the combined effects of an induced current and mechanical pressure. Highly dense $WSi_2$-20vol.%SiC with relative density of up to 97% was produced under simultaneous application of 60MPa pressure and the induced current. The average grain size of $WSi_2$ was about $5.2{\mu}m$. The hardness and fracture toughness values obtained were 1700kg/$mm^2$ and $4.4MPa{\cdot}m^{1/2}$, respectively.

• Journal of Powder Materials
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• v.25 no.1
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• pp.48-53
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• 2018

One-dimensional rutile $TiO_2$ is an important inorganic compound with applicability in sensors, solar cells, and Li-based batteries. However, conventional synthesis methods for $TiO_2$ nanowires are complicated and entail risks of environmental contamination. In this work, we report the growth of $TiO_2$ nanowires on a Ti alloy powder (Ti-6wt%Al-4wt%V, Ti64) using simple thermal oxidation under a limited supply of $O_2$. The optimum condition for $TiO_2$ nanowire synthesis is studied for variables including temperature, time, and pressure. $TiO_2$ nanowires of ${\sim}5{\mu}m$ in length and 100 nm in thickness are richly synthesized under the optimum condition with single-crystalline rutile phases. The formation of $TiO_2$ nanowires is greatly influenced by synthesis temperature and pressure. The synthesized $TiO_2$ nanowires are characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HR-TEM).

• Applied Science and Convergence Technology
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• v.26 no.6
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• pp.164-173
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• 2017

Across the most industry, the demand for nanoparticles is increasing. Therefore, many studies have been carried out to synthesize nanoparticles using various methods. The aim of this paper is to introduce an industry-applicable as well as financially and environmentally effective solution plasma process. The solution plasma process involves fewer chemicals than the traditional kit, and can be used to replace many of the chemical agents employed in previous synthesis of nanoparticles into plasma. In this study, this process is compared to the wet-reaction process that has thus far been widely used in the most industry. Furthermore, the solution plasma process has been classified into four different types (in-solution, out of solution, direct type, and remote type), according to its plasma occurrence position and plasma types. Thus, the source of radicals, nanoparticle synthesis, and modification methods are explained for each design. Lastly, unlike nanoparticles with hydrophilic functional groups that are made inside the solution, a nanoparticle synthesis and modification method to create a hydrophobic functional group is also proposed.

• Journal of the Korean institute of surface engineering
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• v.47 no.6
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• pp.347-353
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• 2014

We present a synthesis of single-walled carbon nanotubes(SWNTs) for enhancement of parallel-alignment and density using chemical vapor deposition with methane feed gas. As-purchased ST-cut quartz substrates were heat-treated and line-patterned by electron-beam lithography in order to grow SWNTs with parallel alignment. We investigated the effects of various synthesis parameters such as catalyst oxidation, reduction, and synthesis conditions in order to enhance both tube density and degree of parallel alignment. The condition of $1{\AA}$ of Fe catalyst film, atmospheric oxidation at $750^{\circ}C$ for 10 min, reduction under 400 Torr for 5 min, and growth at $865^{\circ}C$ under 300 Torr yields $33tubes/10{\mu}m$, which is the highest tube density with parallel alignment. Based on the results of atomic force microscope and Raman spectroscopy, it was found that SWNTs have diameter range of 0.8-2.0 nm. We believe that the present work would contribute to the development of SWNTs-based flexible functional devices.

• Journal of Life Science
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• v.28 no.7
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• pp.802-810
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• 2018

Aging is accompanied by changes in the body, such as graying hair, wrinkles, and black spots composed of lipid peroxides and proteins. Melanin is a polymer substance produced by an oxidation polymerization reaction from tyrosine, and it determines the color of hair and skin. It has been reported that melanin is synthesized by melanocyte, and its excessive production by reactive oxygen species is associated with aging. The purpose of this study was to determine the direct effects of Musa paradisiaca peel ethanolic extract (MPEE) on antioxidative activity and melanin synthesis. It was observed that the antioxidant activity of MPEE was similar to that of vitamin C, a positive control, in both DPPH radical scavenging assay and reducing power assay. In order to examine cytotoxicity prior to cell experimentation, 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed for B16F1 cells. MPEE was not cytotoxic at $32{\mu}g/ml$ or less. In addition, MPEE increased melanin synthesis in live cells in addition to tyrosinase activity and melanin synthesis in dihydroxyphenylalanine (DOPA)-oxidation assay in vitro. Moreover, MPEE increased melanin synthesis in cells aged by pretreatment with $H_2O_2$. The expression levels of tyrosinase-related protein (TRP)-1, TRP-2, and superoxide dismutase (SOD)-2 by western blot analysis were increased in the presence of MPEE. These results suggest that MPEE could promote the melanin synthesis as an antioxidative substance.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.2 s.57
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• pp.117-121
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• 2006

Although many studies have been performed to elucidate the molecular consequence of factors that regulate skin aging, little is known about the effect of green tea catechins except EGCG. The matrix metalloproteinase (MMP), can degrade matrix proteins and results in a collagen deficiency in photodamaged skin, are known to play an important role in photoaging. This study, investigated the effects of green tea catechins on the UVA-induced MMP-1 expression, activity of MMP-2 and synthesis of type I procollagen in human dermal fibroblasts. We examined eight catechins that naturally exist in green tea leaves and compared their efficacies among them. Most of catechins inhibited the expression of MMP-1 in dose dependent manner, and the levels were reduced, especially, 57.4 and 68.2% by treatment with $1{\mu}M$ of epigallocatechin-3-gallate (EGCG) and gallocatechin-3-gallate (GCG), respectively. Also, catechins significantly suppressed the activities of MMP-2. Catechins also induced the expression of type I procollagen, however, they acted only at the concentration below $1{\mu}M$ interestingly. Furthermore, when EGCG:GCG:ECG had the ratio of 0.5:1.5:.1.3, they presented the most effective on procollagen synthesis. Therefore, we concluded that catechins significantly inhibited MMPs and induced collagen synthesis. Taken together, all these results suggested that green tea catechins might be good natural materials act as an anti-photoaging and a skin-aging improving agent.