• KSBB Journal
• /
• v.18 no.4
• /
• pp.282-288
• /
• 2003

For the screening of anti-inflammation and antioxidative activities, ethanolic extract of 40 species of traditional herbal medicines were examined their hyaluronidase inhibitory effect and radical scavenging activity in vitro. From the result of the hyaluronidase inhibitory activity using a Morgan-Elson assay, Astragali Radix, Eucommia Cortex, Schizandrae Fructus, Scutellaria Radix, Acanthopanacis Cortex, Chaenomelis Fructus, Amomum xanthioides Wallich and Moutan Radicis Cortex showed more than 50% hyaluronidase inhibitory effects at the concentration of 10 mg/mL. In the various solvent fractions (n-hexane, chloroform, ethyl acetate, water) prepared from ethanolic extracts, the ethyl acetate fraction of all extracts tested showed strong activity. Antioxidative activity was evaluated by assaying electron-donating ability to DPPH free radical and scavenging of hydroxyl radical (ㆍOH) generated through Fenton reaction, respectively. Rubus coreanus Miq, Moutan Radicis Cortex, Paeoniae Radix Alba, Plantaginis Semen and Sorbus commixta Hedl. showed high activity more than 90%, yet similar activity to $\alpha$-tocopherol and BHA at the concentration of 1 mg/mL in electron donating activity. The scavenging effects of ethanolic extracts on hydroxyl radical were investigated using a 2-deoxyribose oxidation method and tested all extracts showed significant radical scavenging activity. The experiment was also performed to examine whether herbal medicines having significant lipid peroxidation inhibitory activity, Schizandrae-Fructus is the strongest inhibitory activity in both linoleic acid and liposome peroxidation.

• Journal of the Korean Ceramic Society
• /
• v.39 no.2
• /
• pp.159-163
• /
• 2002

A single phase perovskite relaxor ferroelectric PMN-PT-BT was prepared by a single calcination and the modified mixed oxide process. It was accomplished by ball-milling PbO, $Nb_2O_5,\;Ti(OC_3H_7)_4,\;BaCO_3,\;and\;Mg(NO_3)_2$ instead of MgO, removing the solvent, and then followed by calcination at 900$^{\circ}C$ for 2h. The specimen sintered at 1100$^{\circ}C$/2h showed the sintered density of 7.83 g/$cm^3$, room temperature dielectric constant of 22000, and dielectric loss of 2.5%. Addition of 1.0 mole% (0.3 wt%) of Ag as $AgNO_3$ and followed by calcination at 550$^{\circ}C$/2h lowered the sintering temperature to 900$^{\circ}C$. It still showed the sintered density of 7.88 g/$cm^3$, room temperature dielectric constant of 20000 and dielectric loss of 2.4%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.418-418
• /
• 2008

The electrochemical etching of silicon in HF-based solutions is known to form various types of porous structures. Porous structures are generally classified into three categories according to pore sizes: micropore (below 2 nm in size), mesopore (2 ~ 50 nm), and macropore (above 50 nm). Recently, the formation of macropores has attracted increasing interest because of their promising characteristics for an wide scope of applications such as microelectromechanical systems (MEMS), chemical sensors, biotechnology, photonic crystals, and photovoltaic application. One of the promising applications of macropores is in the field of MEMS. Anisotropic etching is essential step for fabrication of MEMS. Conventional wet etching has advantages such as low processing cost and high throughput, but it is unsuitable to fabricate high-aspect-ratio structures with vertical sidewalls due to its inherent etching characteristics along certain crystal orientations. Reactive ion dry etching is another technique of anisotropic etching. This has excellent ability to fabricate high-aspect-ratio structures with vertical sidewalls and high accuracy. However, its high processing cost is one of the bottlenecks for widely successful commercialization of MEMS. In contrast, by using electrochemical etching method together with pre-patterning by lithographic step, regular macropore arrays with very high-aspect-ratio up to 250 can be obtained. The formed macropores have very smooth surface and side, unlike deep reactive ion etching where surfaces are damaged and wavy. Especially, to make vertical microwire or nanowire arrays (aspect ratio = over 1:100) on silicon wafer with top-down photolithography, it is very difficult to fabricate them with conventional dry etching. The electrochemical etching is the most proper candidate to do it. The pillar structures are demonstrated for n-type silicon and the formation mechanism is well explained, while such a experimental results are few for p-type silicon. In this report, In order to understand the roles played by the kinds of etching solution and mask patterns in the formation of microwire arrays, we have undertaken a systematic study of the solvent effects in mixtures of HF, dimethyl sulfoxide (DMSO), iso-propanol, and mixtures of HF with water on the structure formation on monocrystalline p-type silicon with a resistivity with 10 ~ 20 $\Omega{\cdot}cm$. The different morphological results are presented according to mask patterns and etching solutions.

• Journal of Korean Society of Forest Science
• /
• v.99 no.6
• /
• pp.885-890
• /
• 2010

This study was conducted to confirm the application as ingredients of cosmetics through an examination of the function for anti-oxidant activity of the fraction isolated from Pyrus ussuriensis leaves. The dried leaf of Pyrus ussuriensis were extracted with acetone-$H_2O$ (6:4, v/v), concentrated and fractionated with the upper layer of acetone on a separatory funnel. Each fraction was freeze dried, then a portion of acetone soluble powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol as eluents and also used the MIC-gel using a series of aqueous methanol as developing solvent. The isolated compounds were identified by silica-gel TLC. The concentration of total phenolic compound of Pyrus ussuriensis acetate soluble fraction was high, 914 mg/g. The results obtained from the analyses of the anti-oxidanat effects of Pyrus ussuriensis acetate fraction can be summarized as follows: In the result of DPPH scavenging radical activity, Pyrus ussuriensis acetate soluble fraction showed more than 80% at 100 ppm. SOD-like activity of one of Pyrus ussuriensis acetate soluble fractions was 77% at 1000 ppm. Xanthine oxidase inhibition of Pyrus ussuriensis acetate soluble fraction was 38% at 100 ppm. From these results, we confirmed that acetate fraction of Pyrus ussuriensis has a great potential as a natural ingredients with a natural antioxidant and antimicrobial source.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.1
• /
• pp.14-18
• /
• 2009

This study was to determine the inhibitory effect against food borne pathogens of ethanol and water extracts from leaf, stem and root of Orostachys japonicus. On the paper disc assay, no detectable bactericidal activity in the water extracts from leaf, stem and root of Orostachys japonicus and ethanol extracts form stem and root of Orostachys japonicus was shown. However, ethanol extract of Orostachys japonicus leaf showed the highest antimicrobial activity. Minimum inhibitory concentration (MIC) of ethanol extracts was determined to range from 0.05 to 0.1% in leaf of Orostachys japonicus against gram positive bacteria and yeast. Antimicrobial activity of ethanol extracts was stable by heating at $121^{\circ}C$ for 15 min, and not affected by pH $2{\sim}10$ except for B. subtilis. These findings suggest ethanol extract from leaf of Orostachys japonicus may be useful as natural preservative.

• Journal of Life Science
• /
• v.30 no.8
• /
• pp.688-694
• /
• 2020

In a previous study, the total phenolic content in ethanol extracts of medicinal plants that naturally grow on Jeju Island were analyzed with the extracts of Raphiolepsis indica leaf found to have the highest. The current study was carried out to evaluate the total flavonoid content, radical-scavenging activity, and the protective effect of R. indica extracts and solvent fractions on oxidative stress in HaCaT keratinocytes. More specifically, total flavonoid content and 2-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical-scavenging activity were measured to assess anti-oxidative activity, and protective effects against hydrogen peroxide (H₂O₂) were determined by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay on the HaCaT cells. Of the various fractions analyzed, the ethyl acetate extract of R. indica showed the highest total flavonoid content (149.13 mg/g extracts) and the lowest remaining ABTS. In addition, the ethyl acetate fraction was significantly more resistant against H₂O₂ than the negative control. Our results therefore suggest that an ethyl acetate fraction of R. indica protects HaCaT cells against oxidative stress and could prove useful for developing functional cosmetic materials.

• Journal of the Korean Chemical Society
• /
• v.56 no.5
• /
• pp.583-590
• /
• 2012

The HF (Hollow fiber) extraction method was optimized to analysis seven species of pesticides in aqueous sample and analyzing samples by GC/MS. Hollow fiber extraction showed good efficiency when it was conducted under these conditions: organic solvent was toluene and agitation speed was 1200 rpm. The 15% concentration of NaCl was optimized when it was experimented between 5% and 25%. The equilibrium time was determined at 15 minutes. The pH 5 showed the best effect on the extraction efficiency. The linearities of calibration curves of seven species were good with correlation of regression ($r^2$) over 0.995 when they were experimented over a concentration range of $5{\mu}g/L$ to $50{\mu}g/L$. The analytical data exhibited the detection of limits (LODs) range of $0.37{\mu}g/L$ to $1.23{\mu}g/L$ and the limit of quantification (LOQs) range of $1.19{\mu}g/L$ to $3.91{\mu}g/L$. The optimized HF-LPME extraction method provides a simple and effective preparation and requires small amount of organic solvents and samples compared to conventional pre-treatment methods.

• Applied Chemistry for Engineering
• /
• v.10 no.4
• /
• pp.523-530
• /
• 1999

Acrylic pressure-sensitive adhesive has been made utilizing organic solvents, but nowadays it is made by solvent-free system due to environmental problems. In this study, emulsion polymerization were carried out at $40^{\circ}C$ with methacrylic acid(MAA), n-butyl acrylate(n-BA) and 2-ethylhexyl acrylate(2-EHA) as monomers in the presence of anionic(sodium dodecyl sulfate, SDS) and nonionic(ethylene oxide types) surfactant mixtures. The overall conversion of the polymerization reaction in a mixed surfactant system was found to be higher than that in a single surfactant system. Emulsion stability in mixed or anionic surfactant systems was found to be over 12 week, which was better than that in nonionic surfactant system. Emulsion particle size decreased as surfactant content increased. The Tg and molecular weight of emulsion polymer were inependent of the type, the amount and the mixing ratio of surfactant. Based on the results of stability and peel strength, the optimum nonionic surfactant ratio in total 4 g of surfactant mixture systems is found to be 40~60% by weight where the nonionic surfactant has 50 ethylene oxide groups and 16~18 carbon atoms in hydrophobic alkyl chain.

• Korean Journal of Environmental Biology
• /
• v.21 no.2
• /
• pp.170-176
• /
• 2003

The effect of xenobiotics on cytochrome P450 (CYP) and 7-ethoxyresorufin-O-deethylase (EROD) in hepatopancreatic microsome of surf clam, Coelomactra anti-quata, were investigated. The microsome isolated from the digestive gland of the surf clam, collected from the east coast of Korea, was in vitro exposed to p, p -DDT (0.1,0.4 and 1.0 mM) for 30 min and 2,3,7,8-TCDD (0.01, 0.04 and 0.1 ppb) and PCB-153 (0.01, 0.04 and 0.1 ppb) for 7 hr. In the case of DDT exposure, the CYP content and EROD activity of 1.0 mM exposure group increased up to about 117% and 120% of the DMSO solvent control group after 10 min. exposure, respectively. After 2 hr exposure of TCDD, the CYP content and EROD activity were also induced to the range of 103∼110% and 121∼139%, respectively. The PCB-153 exposure group showed 107∼115% of CYP content and 129∼140% of EROD activity after 2 hr exposure. Three test chemicals apparently induced CYP and EROD activity in the microsome of surf clam. The inducing potentials depend en the test chemicals.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.15 no.2
• /
• pp.144-152
• /
• 2005

To evaluate the effect of lead biomarkers including bone lead on neurobehavioral test in lead workers, 652 lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 102 non-occupationally lead exposed blue collar workers in general manufacturing industries were also joined this study. All study subjects joined this study with written informed consent. The study variables of lead exposure were blood and patella lead. For the general characteristics of study subjects, standardized questionnaire regarding age, sex, past disease history, job duration, body mass index (BMI), drinking and smoking habit were provided. For the past history of neurotoxicity related diseases, all study subjects were interviewed by qualified occupational health physician. The results obtained were as follows: 1. Compared with controls without occupational lead exposure, lead exposed subjects had worse performance on all tests(p<0.05). 2. After adjustment for covariates (age, sex, job duration, education level, BMI, smoking and drinking status), the signs of the regression coefficients for blood lead were negative for 13 of the 14 tests. Blood lead was a significant predictor of poorer scores on 8 tests (simple reaction time(ms & root MSD), Trail-Making Test B, Digit Symbol Substitution, Purdue Pegboard assembly, Digit Span Test, Benton Visual Retention, and Purdue pegboard both hand). 3. After adjustment for covariates (age, sex, job duration, education level, BMI, smoking and drinking status), the signs of the regression coefficients for patella lead were negative for 12 of the 14 tests. Patella lead was a significant predictor of poorer scores on 8 tests (simple reaction time(ms). Purdue Pegboard assembly, Digit Span Test, Benton Visual Retention. Pursuit Aiming rest (no. of correct & no. of incorrect), Purdue pegboard non-dominant hand and both hand). With above results, blood lead and patella lead were associated with poorer performance of neurobehavioral tests. In addition, patella lead was confirmed to be better predictor of manual dexterity test in neurobehavioral test battery in lead workers