• Herbal Formula Science
• /
• v.14 no.2
• /
• pp.67-75
• /
• 2006

The natural plants were screened for new cosmetic materials. Many parts of Nelumbo nucifera has been investigated for anti-wrinkling and anti-furrowing effects. The leaves. flowers and stamens of Nelumbo nucifera were extracted with ethanol or distilled water. The effects of cell viability and $H_2O_2-induced$ cytotoxicity were studied on CCD-986sk human fibroblast cell line by MTT assay. We measured various effects related to skin such as the synthesis of MMP-1 and type I procollagen. The ethanol extract of Nelumbo nucifera leaves (ENL) at concentrations of 30 ${\mu}g/ml$ showed maximum cell viability on CCD-986sk cells by 129.70%. and $H_2O_2-induced$ cytotoxicity was blocked by ENL (5. 10. 20. 30. and 40 ${\mu}g/ml$) concentration-dependently. The synthesis of MMP-1 and type I procollagen were positive in ENL. These results suggest that ENL has anti-oxidant and anti-furrowing effects.

• The Journal of the Acoustical Society of Korea
• /
• v.14 no.5
• /
• pp.63-73
• /
• 1995

The conventional acoustic sounds can be synthesized by Frequency Modulation which includes the variation of frequency, amplitude, and modulation index. In this paper the number of variable synthesis parameters are limited to easily implement the existing two carrier FM algorithm by hardware. The DSP(Digital Signal Processor), which is able to carry out the modified algorithm and synthesize 16 sounds at a time, is designed with $0.8{\mu}m$ standard sells. The DSP which can synthesize 2 sounds at a time is implemented by ASIC emulator to examine the sound quality of the designed DSP. Through the objective and subjective estimation, it is confirmed that the sounds of many instruments from the implemented DSP are very closed to their real sound. Finally the designed DSP is layouted and simulated by VLSI desgn tool. According to the simulation, the designed DSP has the sufficiently fast speed for synthesizing 16 sounds at a time.

• Journal of Energy Engineering
• /
• v.19 no.1
• /
• pp.16-20
• /
• 2010

In present work, tin-carbon mixtures by using carbon from pyrolyzed coffee seeds were synthesized. Synthesis methods includes simple mixing and chemical mixing. X-ray diffraction pattern indicated carbon and tin mixture peaks and scanning electron microscope images showed particles size of $12{\sim}85\;{\mu}m$ and shape. Charge discharge test were carried out. Tin-carbon mixture by chemical mixing indicated higher discharge capacity of 191 mAh/g than commercial carbon black(105 mAh/g) for 15cycles. Tin-carbon mixture by simple mixing indicated similar performance to carbon black.

• Biomolecules & Therapeutics
• /
• v.15 no.4
• /
• pp.261-265
• /
• 2007

Hydroxyproline (HYP) is a post-translational product of proline hydroxylation catalyzed by an enzyme prolyl 4-hydroxylase (P4H) which plays a crucial role in the synthesis of all collagens. Considering the role of collagen and its significance in many clinically important diseases such as liver fibrosis, a great deal of attention has been directed toward the development of an assay at cell-based system. The reason is that cell-based assay system is more efficient than enzyme-based in vitro system and takes much less time than in vivo system. Several assay procedures developed for P4H are laborious, time-consuming and not feasible for the massive-screening. Here, we report the cell-based assay method of prolyl 4-hydroxylase in immortalized rat hepatic stellate HSC-T6 cells. To optimize the cell culture condition to assay for HYP content, various concentrations of reagents were treated for different times in HSC-T6 cells. Our data showed that the treatment with ascorbate in a hypoxic condition for 24 h resulted in the maximal increase of HYP by 1.8 fold. Alternatively, cobalt chloride ($5\;{\mu}M$) and ascorbate ($50\;{\mu}M$) in normoxic states exhibited similar effect on the production of HYP as in a hypoxic condition. Therefore, cobalt chloride can be substituted for a hypoxic condition when an anaerobic chamber is not available. Rosiglitazone and HOE077, known as inhibitors of collagen, synthesis decreased P4H enzyme activity by 32.3% and 15%, respectively, which coincided with previous reports from liver tissues. The level of the smooth muscle ${\alpha}$-actin, a marker of activated stellate cells, was significantly increased under hypoxia, suggesting that our experimental condition could work for screening the anti-fibrotic compounds. The assay procedure took only 3 days after treatment with agents, while assays from the primary stellate cells or liver tissues have taken several weeks. Considering the time and expenses, this assay method could be useful to screen the compounds for the inhibitor of prolyl 4-hydroxylase.

• Tribology and Lubricants
• /
• v.15 no.1
• /
• pp.77-82
• /
• 1999

The processing conditions fur the synthesis of platelet W $S_2$ lubricant powder through a solid-gas reaction were optimized. The mixture of tungsten and sulfur powders were sealed in a vacuum of 10$^{-6}$ torr, prior to heat-treating at 85$0^{\circ}C$ fur 8 days. The reaction product showed a well-developed platelet W $S_2$ powder with an average size of 3.8 ${\mu}{\textrm}{m}$. The TGA/DTA analysis of the synthesized W $S_2$ powder was performed up to 120$0^{\circ}C$ at a rate of 1$0^{\circ}C$/min in flowing air (100 ${\mu}{\textrm}{m}$/min) atmosphere. The weight loss was about 6% up to 120$0^{\circ}C$ compared to the original weight. A rapid weight loss of about 5% occurred in the temperature range of 44$0^{\circ}C$ to 66$0^{\circ}C$ and an exothermic peak observed due to the transition of W $S_2$ to W $O_3$. The synthesized W $S_2$powder was coated on the commercial deep grooved ball bearing (No. 6203) to examine the effect of W $S_2$, coating layer on the noise and endurance of the ball bearing. The level of noise obtained from W $S_2$, coated-ball bearing (56 ㏈) was higher. than the value (32 ㏈) occurred in the case of greece lubrication. The endurance of the ball-bearing assembled after the coating of W $S_2$ powder onto each part increased 50 times compared to the non-coated ball-bearing..

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.2
• /
• pp.152-164
• /
• 1995

$xPb(Fe_{1/2}Nb_{1/2})O_3 - (1 - x)Pb(Mg_{1/3}Nb_{2/3})O_3$ powders were synthesized by the molten salt synthesis method using the NaC!- KCI flux with 1 : 1 molar ratio, and their powders and dielectric properties were investigated. The synthesized powders showed less agglomerated shape with the average particle size of less than $2 \mu\textrm{m}$. The composition $x0.3Pb(Fe_{1/2}Nb_{1/2})O_3-0.7Pb(Mg_{1/3}Nb_{2/3})O_3$ could be sintered at $1000{\times}C$ and its dielectric constnat was over 11, 000.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.5
• /
• pp.401-409
• /
• 2013

Numerical analysis on RF (Radio-Frequency) thermal plasma treatment of micro-sized Ni metal was carried out to understand the synthesis mechanism of nano-sized Ni powder by RF thermal plasma. For this purpose, the behaviors of Ni metal particles injected into RF plasma torch were investigated according to their diameters ($1{\sim}100{\mu}m$), RF input power (6 ~ 12 kW) and the flow rates of carrier gases (2 and 5 slpm). From the numerical results, it is predicted firstly that the velocities of carrier gases need to be minimized because the strong injection of carrier gas can cool down the central column of RF thermal plasma significantly, which is used as a main path for RF thermal plasma treatment of micro-sized Ni metal. In addition, the residence time of the injected particles in the high temperature region of RF thermal plasma is found to be also reduced in proportion to the flow rate of the carrier gas In spite of these effects of carrier gas velocities, however, calculation results show that a Ni metal particle even with the diameter of $100{\mu}m$ can be completely evaporated at relatively low power level of 10 kW during its flight of RF thermal plasma torch (< 10 ms) due to the relatively low melting point and high thermal conductivity. Based on these observations, nano-sized Ni metal powders are expected to be produced efficiently by a simple treatment of micro-sized Ni metal using RF thermal plasmas.

• Korean Journal of Materials Research
• /
• v.8 no.11
• /
• pp.987-992
• /
• 1998

Titanium aluminide intermetallic compound was formed from high purity elemental Ti and A1 foils by selfpropagating, high-temperature synthesis(SHS1 in hot press. Formation of $TiAl_3$ intermetallics at the interface between Ti and Al foil was observed to be controlled by temperature, pressure and heating rate. Especially, the heating rate is the most important role to form intermetallic compound by SHS reaction. According to DTA experiment, the SHS reactions appeared at two different temperatures below and above the melting point of Al. It was also observed that both SHS reaction temperatures increased with increasing the heating rate. After the SHS reaction of alternatively layered 10 Ti and 9 A1 foils at the heating rate of $20^{\circ}C$/min, the $700\mu\textrm{m}$ thick titanium aluminide sheet was formed by heat treatment at $810^{\circ}C$ for 4hours.

• The Korean Journal of Mycology
• /
• v.16 no.3
• /
• pp.121-127
• /
• 1988

For selective purification of protein in Pleurotus cornucopiae (Per.) Rolland, affinity chromatography was performed by benzoyl-AH-Sepharose 4B gel synthesized using AH-Sepharose 4B with starting materials. Ligand capacity of benzoyl group was 9.3 micromole per milliliter of gel. Total apparent molecular weight of affinity protein was 255KD, which were protein complex of 29.5, 31.5 34.0, 71.0 and 89.0KD, respectively. The contents of nonpolar, polar, positively charged, and negatively charged amino acid were 45.68%, 26.93%, 11.81% and 15.58%, respectively. The nonpolar protein was selectively purified by hydrophobic ligand of benzoyl group of gel.

• Applied Chemistry for Engineering
• /
• v.17 no.3
• /
• pp.260-266
• /
• 2006

For the synthesis of polyurethane memory foam stabilizer with fine cells, hydrosilylation reaction with various polyalkyleneoxides and hydrogen functional group of polymethylhydrogensiloxane (D = 75, D' = 15) was conducted. Polyalkyleneoxides (PAO) used in this research were ethylene oxides or ethylene-co-propylene oxides with terminal groups of hydroxides or methyl groups. To analyze the molecular structures and molecular weights as well as the reaction yields (98%), NMR and GPC analysis were executed. Synthesized siloxane surfactants modified with polyalkylene (EO = 12 units) were applied to producing flexible polyurethane fine memory foams from 0.6 pphp to 2.0 pphp. By controlling the amount of the surfactant, physical characteristics, the polyurethane memory foam with cell size (minimum $0.868{\mu}m$), air flows (-78 KPa), and recovery times (8 sec) were achieved.