• Mycobiology
• /
• v.40 no.2
• /
• pp.138-141
• /
• 2012

We measured physiological functionalities, including antihypertensive angiotensin I-converting enzyme inhibitory activity and immun-stimulating ${\beta}$-glucan content for sixty kinds of Makgeolli that is commercially available from the market. As a result, we selected R-12 commercial raw Makgeolli, with a high content of immuno-stimulating ${\beta}$-glucan, and R-14 commercial raw Makgeolli, exhibiting high antihypertensive activity. Due to the similarities in their overall physicochemical properties and raw materials used for fermentation, we compared the microbial flora in order to investigate the reason for the differences in their functionalities. Nested PCR and denaturing gradient gel electrophoresis for yeasts and bacteria were performed for analysis of microbial diversity of two different kinds of Makgeolli (i.e., R-12, R-14), which showed immuno-stimulating ${\beta}$-glucan content and exhibited a very high level of antihypertensive activity, respectively. Analysis of the 18S rDNA amplicon revealed a major presence of the yeast strain Pichia burtonii in every Makgeolli sample. Analysis of the 16S rDNA amplicon revealed a predominance of lactic acid bacteria, and the most frequent lactic acid bacteria were Lactobacillus ingluviei, L. fermentum, and L. harbinensis, and Lactobacillus sp. Among these, L. harbinensis was detected only in R-12 and L. ingluviei was found only in R-14. Different functionalities from the individual commercially available Makgeolli may be attributed to actions of different microbial flora during fermentation.

• Journal of the Korean Ceramic Society
• /
• v.51 no.5
• /
• pp.459-465
• /
• 2014

In this study, Si-SiC composites were fabricated using a Si melt infiltration method using ${\beta}$-SiC/C composite powders synthesized by the carbothermal reduction of $SiO_2-C$ precursors made from a TEOS and a phenol resin. The purity of the synthesized SiC-C composite powders was higher than 99.9993 wt% and the average particle size varied from 4 to $6{\mu}m$ with increasing carbon contents of the $SiO_2-C$ precursors. It was found that the Si-SiC composites fabricated in this study consist of ${\beta}$-SiC and residual Si, without any trace of ${\alpha}$-SiC. The 3-point bending strengths of the fabricated Si-SiC composites were measured and found to be higher than 550 MPa, although the density of the fabricated Si-SiC composite was less than $2.9g/cm^3$. The bending strengths and the densities of the fabricated Si-SiC composites were found to decrease with increasing C/Si mole ratios in the SiC-C composite powders. The specific resistivities of the Si-SiC composites fabricated using the SiC-C composite powders were less than $0.018{\Omega}cm$. With increasing C content in the SiC-C composite powders used for the fabrication of Si-SiC composites, the specific resistivity of the Si-SiC composites was found to slightly increase from 0.0157 to $0.018{\Omega}cm$.

• Clean Technology
• /
• v.19 no.1
• /
• pp.22-29
• /
• 2013

A comparison of photo-efficiency on dye-sensitized solar cells (DSCs) assembled by using $TiO_2$ materials with different structures and crystallite sizes were investigated in this study. The size and structure of $TiO_2$ have been controlled by pHs and calcination temperatures using solvothermal and sol-gel methods, respectively. Six types of $TiO_2$ samples are obtained; 8.9, 12.8, and 20.2 nm sized $TiO_2$ particles, and the other types using sol-gel method were anatase-rutile mixtures on the structure. The highest photo-efficiency which is remarkable result reached to 8.6% over DSC assembled by anatase $TiO_2$ with 20.2 nm particle size.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.42 no.1
• /
• pp.1-8
• /
• 2005

We fabricate PLT(5) thin film on Pt/TiO/sub x/SiO₂/Si substrate by using sol-gel method and investigate leakage current, switching and retention properties. The leakage current density of PLT(5) thin film is 3.56×10/sup -7/A/㎠ at 4V. In the examination of switching properties, pulse voltage and load resistance were 2V～5V and 50Ω～3.3kΩ, respectively. Switching time has a tendency to decrease from 0.52㎲ to 0.14㎲ with the increase of pulse voltage, and also the time increases from 0.14㎲ to 13.7㎲ with the increase of load resistance. The activation energy obtained from the relation of applied pulse voltage and switching time is about 135kV/cm. The error of switched charge density between hysteresis loop and experiment of polarization switching is about 10%. Also, polarization in retention decreases as much as about 8% after l0/sup 5/s.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.16
• /
• pp.7053-7060
• /
• 2015

In the present work, novel orange peel was extracted with 100%EtOH (ethanol) and fractionated into four fractions namely F1, F2, F3, F4 which were eluted from paper chromatographs using 100%EtOH, 80%EtOH, 50%EtOH and pure water respectively. The crude extract and its four fractions were evaluated for their total polyphenol content (TPC), total flavonoid content (TFC) and radical scavenging activity using DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Their cytotoxic activity using WST assay and DNA damage by agarose gel electrophoresis were also evaluated in a human leukemia HL-60 cell line. The findings revealed that F4 had the highest TPC followed by crude extract, F2, F3 and F1. However, the crude extract had the highest TFC followed by F4, F3, F2, and F1. Depending on the values of $EC_{50}$ and trolox equivalent antioxidant capacity, F4 possessed the strongest antioxidant activity while F1 and F2 displayed weak antioxidant activity. Further, incubation HL-60 cells with extract/fractions for 24h caused an inhibition of cell viability in a concentration-dependent manner. F3 and F4 exhibited a high antiproliferative activity with a narrow range of $IC_{50}$ values ($45.9-48.9{\mu}g/ml$). Crude extract exhibited the weakest antiproliferative activity with an $IC_{50}$ value of $314.89{\mu}g/ml$. Analysis of DNA fragmentation displayed DNA degradation in the form of a smear-type pattern upon agarose gel after incubation of HL-60 cells with F3 and F4 for 6 h. Overall, F3 and F4 appear to be good sources of phytochemicals with antioxidant and potential anticancer activities.

• Geomechanics and Engineering
• /
• v.12 no.5
• /
• pp.831-847
• /
• 2017

Conventional geotechnical engineering soil binders such as ordinary cement or lime have environmental issues in terms of sustainable development. Thus, environmentally friendly materials have attracted considerable interest in modern geotechnical engineering. Microbial biopolymers are being actively developed in order to improve geotechnical engineering properties such as aggregate stability, strength, and hydraulic conductivity of various soil types. This study evaluates the geotechnical engineering shear behavior of sand treated with xanthan gum biopolymer through laboratory direct shear testing. Xanthan gum-sand mixtures with various xanthan gum content (percent to the mass of sand) and gel phases (initial, dried, and re-submerged) were considered. Xanthan gum content of 1.0% sufficiently improves the inter-particle cohesion of cohesionless sands 3.8 times and more (up to 14 times for dried state) than in the untreated (natural) condition, regardless of the xanthan gum gel condition. In general, the strength of xanthan gum-treated sand shows dependency with the rheology and phase of xanthan gum gels in inter-granular pores, which decreases in order as dried (biofilm state), initial (uniform hydrogel), and re-submerged (swollen hydrogel after drying) states. As xanthan gum hydrogels are pseudo-plastic, both inter-particle friction angle and cohesion of xanthan gum-treated sand decrease with water adsorbed swelling at large strain levels. However, for 2% xanthan gum-treated sands, the re-submerged state shows a higher strength than the initial state due to the gradual and non-uniform swelling behavior of highly concentrated biofilms.

• Journal of the Korean Society of Industry Convergence
• /
• v.21 no.1
• /
• pp.9-16
• /
• 2018

Aloe gel layer is well known as raw materials of medicines and cosmetics due to their antioxidant and anti-inflammatory properties. In aloe gel extracting process, the outer part of the leaf was removed. It contains high quality of fiber and many nutrients. However, this part is thrown away and generally used as fertilizer. The purpose of this research was to examine the important nutrient of Aloe saponaria. Moreover, the feasibility of using aloe as a dietary supplement by feeding fermentation treatment of aloe was investigated. To do this, the aloe leaf was divided into several parts including leaf skin, bottom of the leaf, tip of the leaf, middle of the leaf, and leaf flesh. Then the saponin content were analyzed from each part. The extraction method was used to clarify the saponin content. The aloe then fermented to improve it benefit. The fermented Aloe then given as dietary food to group of pig. Finally, the appropriate feed level was determined and the pork meat quality was analyzed. The extraction of saponin shows that the highest concentration of saponin located on the skin of the leaf. The feeding experiment shows that there is no significant difference in pig growth without aloe dietary food and groups with aloe as dietary food. It was conclude that fermented aloe can replace the pigs normal feeder as an alternative feeding solution.

• Journal of Sensor Science and Technology
• /
• v.4 no.4
• /
• pp.75-80
• /
• 1995

In order to fabricate the piezoelectric thin film of the PZT-PNN ternary compound, the metal alkoxides were used as starting materials. The electrical and crystalline properties of the thin film were evaluated. The X- RD study shows that the crystallization of the film is optimized at $550^{\circ}C$ of sintering temperature. According to the D-E hysterisis curve, the coercive field is 28.8 kV /cm, and the remanent polariztion is $18.3\;{\mu}C/cm^{2}$. The break down voltages of the thin films are $76.0\;{\sim}\;27.0\;MV/m$. When the sintering temperature is raised, the break down voltage is lowered. As a result of measuring the C-V characteristic curve of the ternary compound piezoelectric thin film, the relative dielectric constants are 406 for the composition (50:40:10), 1084 for the composition (50:30:20), 723 for the composition (45:35:20) and 316 for the composition (40:40:20).

• Applied Chemistry for Engineering
• /
• v.7 no.5
• /
• pp.823-831
• /
• 1996

At the ratio [$H_2O$]/[TEOS]=1.7, the silica sol was synthesized by partial hydrolysis in the presence of acid catalyst. After stabilizing the silica sol by trimethylsilylation, the molecular weight and viscosity of the sol obtained at various reaction times were examined to determine a best spinnability of the sol. Gel fibers were prepared from the sol solution after removing solvent in the solution, and the gel fibers were heated at $1,000^{\circ}C$. The prepared silica fibers were in the shape of circular cross-section and their tensile strength and $SiO_2$ purity were $83{\pm}20kg/mm^2$ and about 99.997%, respectively.

• The Korean Journal of Nuclear Medicine
• /
• v.4 no.1
• /
• pp.43-49
• /
• 1970

In recent years with development of immuno-electrophoresis, more acurate analysis of the serum protein became possible. However, there is few reports in the literature which investigated the changes of the immunoglobulin compared with electrophoretically fractioned serum thyroglobulin in the patients with various thyroid diseases. The purpose of this report is to investigate the changes of thyroglobulin in various thyroid diseases by the method of immuno-electrophoresis and to compare the results with.serum protein fractionated by the method of agar-gel micro-electrophoresis. Materials and Methods: Sera from 9 patients with diffuse toxic goiter, 2 nodular nontoxic goiter, 2 thyroiditis, 3 hypothy, roidism, 1 thyroid cancer, 7 cystic degeneration of the thyroid gland, and 10 normal subject were taken. All cases were confirmed by various laboratory thyroid function tests and thyroid needle biopsy. Immuno-electrophoretic analysis of the serum were performed by Scheidegger's modified micro-immuno-electrophoretic method. The antiserum was obtained from the Travenol Laboratories International, Hyland Products Division and was rabbit anti-human thyroglobulin. Microscope slide agar-gel electrophoresis for serum protein fractionation was performed at $4^{\circ}C$ using veronal buffer, pH 8.6 and ionic strength 0.05, with 54 volts and 2.8 mA for 60 minutes. The fractionated slide was stained with 0.1% thiazine red. The results were as follows: 1) Increase of immune-globulin macroglobulin (IgM), alphaglobulin, and immune-globulin A (IgA) by 95.8%, 100%, 29.2% respectively was found in the serum from various thyroid diseases. 2) Thyroglobulin fraction was found to be increased in 50%, no change in 41.7%, and no line in 8.3% with all of the various goiter patients. On the other hand, 10 normal control group showed only 2 cases of increase, 5 cases of no change and 3 cases of no line.