• Journal of Radiation Industry
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• v.10 no.4
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• pp.205-210
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• 2016

This study was conducted to evaluate the combined effect of gamma irradiation and different conditions (vacuum packaging, antioxidant and freezing) on the microbiological and sensory characteristics of freeze dried Manila clam porridge (MCP) for immuno-compromised patient food. MCP can be sterilized at 1 kGy to 10 kGy. The initial counts of total aerobic bacteria and yeast molds in the non-irradiated MCP were $2.4{\pm}0.5$ and $1.2{\pm}0.3{\log}\;CFU\;g^{-1}$, respectively, but gamma irradiation significantly decreased the total aerobic bacteria to below the detection limit ($1{\log}\;CFU\;g^{-1}$) (5 kGy). Moreover, gamma irradiation effectively eliminated yeasts/molds at dose below than 1 kGy. However, gamma irradiation accelerated the increase of lipid oxidation and therefore, decreased the sensory characteristics of MCP as irradiation dose increased. To improve the sensory qualities of gamma irradiated MCP, combination treatment (vacuum packaging, 0.1% vitamin C) were applied. There was no significant difference in the overall acceptance scores between the combined-treatment sample (5.6 points) and the non-irradiated samples (6.0). The results indicate that combination treatment (vacuum packaging, 0.1% vitamin C) may help to maintain the quality of MCP. Therefore, it considered that irradiation of MCP with combined treatment and this is an effective method for the consumption as a special purpose food such as for space travel or immuno-compromised patients.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1857-1864
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• 2018

Phthalate plasticizers residue in food is a serious threat to public health. Spores of Ganoderma lucidum are easy to be contaminated with phthalates during collection and processing. In this study, supercritical fluid extraction (SFE) was performed to remove phthalates in spores of G. lucidum, and the effects on acid and peroxide values of spores' oil were also evaluated. The results showed SFE removed 100% of the residual di-iso-butyl phthalate, di-n-butyl phthalate and di-2-ethylhexyl phthalate in the spores of G. lucidum. No significant differences in polysaccharides content and fatty acid composition were observed between SFE and control spores. However, the triterpenoid extracts of SFE spores had a 7.45% increase, significantly higher than that in control spores. Accelerated oxidation tests further implied that SFE could improve the stability of spores' oil. Our results suggested SFE is a potential approach to remove phthalate from food related products.

• Elastomers and Composites
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• v.55 no.4
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• pp.270-276
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• 2020

The long-term durability of an FKM O-ring used as parts of a hydrogen station was investigated by exposing it to high-pressure gaseous hydrogen for 1, 3, and 7 days at room temperature. Changes in its sealing force were subsequently measured at 150℃ using intermittent compression stress relaxation (CSR). No changes in the tensile properties of FKM O-ring were observed, but its initial and overall sealing forces at 150℃ significantly decreased with increasing exposure time to hydrogen gas. Microvoid formation in the FKM O-ring upon exposure to high-pressure hydrogen was minimized over time after the ring was exposed to atmospheric pressure at room temperature, which prevented changes in its tensile properties. However, applying heat accelerated FKM O-ring oxidation, which decreased its sealing force. These results indicated that identifying changes in the sealing force of rubber materials using intermittent CSR is not sufficient for monitoring changes in mechanical properties under high-pressure hydrogen atmospheres; however, it is suitable for evaluating the long-term durability of sealing materials for hydrogen station applications under similar conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3252-3260
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• 2012

2,2'-Bipyridinium chlorochromate[$C_{10}H_8N_2HCrO_3Cl$] was synthesized by the reaction of 2,2'- bipyridine with chromium(VI) trioxide in 6M HCl. The structure was characterized by IR and ICP analysis. The oxidation of benzyl alcohol using 2,2'-bipyridinium chlorochromate in various solvents showed that the reactivity increased with the increase in the order of the dielectric constant(${\varepsilon}$), in the order: cyclohexene< chloroform$p-CH_3$, H, m-Br, $m-NO_2$) in N,N'-dimethylformamide. Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.64(303K). The oxidation reactivity of alcohols can be a useful factor to study about physical properties such as thermal stability, when the polysilsesquioxane solution is ready for an applying coating agent. The observed experimental data was used to rationalized the hydride ion transfer in the rate-determining step.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1108-1113
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• 2005

Advanced oxidation process involving $O_3/H_2O_2$ was used to eliminate 1,4-dioxane and to enhance the biodegradability of dioxane-contaminated water. Oxidation process was carried out in a bubble column reactor under different pH and $H_2O_2$ concentrations. The removal efficiencies of 1,4-dioxane were investigated at hydrogen peroxide concentration between 40 and 120 mg/L. At the same pH, removal efficiencies of 1,4-dioxane increased with increasing initial $H_2O_2$ concentration. There was a linear relationship between initial concentration of $H_2O_2$ and the amount of consumed $O_3$. It was observed that the high $H_2O_2$ concentration accelerated the generation of hydroperoxy ions(${HO_2}^-$) and hydroxyl radicals($OH{\cdot}$). Hydrogen peroxide enhanced the decomposition of 1,4-dioxane and the biodegradability of the solution.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.307-319
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• 2008

STATEMENT OF PROBLEM: It is known that an anodic oxidation technique, one of the methods for the implant surface treatment, remarkably increased surface area, enhanced wettability and accelerated the initial bone healing. Purpose: This study was performed to evaluate the wettability of anodized titanium surface which has a nanotubular structure, to assess osseointegration after the placement of implant with nano-size tubes on tibia of rats and to analyze quantitatively transferable rhBMP-2 on each surface. MATERIAL AND METHOD: Four different kinds of surface-treated titanium discs (polished (machined surface) group, micro (blasting surface) group, nano (anodizedmachined surface) group, and nano-micro (anodized-blasting surface) group) were fabricated (n=10). Three different media were chosen to measure the surface contact angles; distilled water, plasma and rhBMP-2 solution. After a single drop (0.025 $m{\ell}$) of solution, the picture was taken with the image camera, and contact angle was measured by using image analysis system. For the test of osseointegration, 2 kinds of anodized surface (anodized-machined surface, anodized-blasting surface) implants having 2.0 mm in diameter and 5.0 mm in length inserted into the tibia of Wistar rats. After 3 weeks, tibia were harvested and the specimens were stained with hematoxylin and eosin for histological analysis. To test the possibility of drug delivery, after soaking sample groups in the concentration of 250 ng/$m{\ell}$l of rhBMP-2 for 48 hours, the excess solution of rhBMP-2 were removed. After that, they were lyophilized for 24 hours, and then the rhBMP-2 on the surface of titanium was resolved for 72 hours in PBS. All the extracted solution was analyzed by ELISA. One-way analysis of variance (ANOVA) was performed on the data. RESULTS: The wettability is improved by anodic oxidation. The best wettability was shown on the nano-micro group, and it was followed by nano group, micro group, and polished group. In the histological findings, all implants showed good healing and the new bone formation were observed along the implant surface. After 3 days, nano-micro group delivered the most amount of rhBMP-2, followed by nano group, micro group, and polished group. CONCLUSION: It indicated that anodic oxidation on blasting surface produce functionally graded nano-micro porous structure and enhance hydrophilicity of the surface and osseointegration. The findings suggest that the nano-micro porous structure could be a useful carrier of osteogenic molecules like rhBMP-2.

• Journal of the Korean Ceramic Society
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• v.32 no.5
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• pp.626-634
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• 1995

The SiC-porcelain powder mixtures containing 51.9wt% SiC are produced as by-products from the surface abrasion process of porcelain cores. This raw powders were used as starting materials for the synthesis of SiC containing ceramics. The specimen, which was fired at 135$0^{\circ}C$ from raw powders, had SiC, $Al_{2}O_{3}$, , cristobalite, mullite as crystalline phases, and the fractured microstructure showed dispersed SiC crystalline particles almost wetted with glassy matrix and spherical pores. Although the oxidation of SiC containing powder compacts wetted with glassy matrix and spherical pores. Although the oxidation of SiC containing powder compacts started at the range of 600~80$0^{\circ}C$ form the analysis of weight gain, the presence of $SiO_{2}$ crystallien phase and cristobalite was confirmed at 100$0^{\circ}C$ by XRD analysis. Mullitization of specimens was accelerated by preheating before the final firing. The specimen sintered at 135$0^{\circ}C$ after 100$0^{\circ}C$ preheating consisted of SiC, cristobalite, mullite as crystalline phases, and revealed 2.24g/$cm^{3}$ bulk density, 11.73% water adsorption, porous microstructure with small amount of glassy phase. SiC contents of specimens, which was 51.9 wt% in the raw powders, reduced to 37~22 wt% after firing at 135$0^{\circ}C$ depending on the preheating condition.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.264-271
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• 1999

This study was conducted to know the storage stability of Yackwa, a traditional Korean fried cookie, prepared by two different cooking methods; deep fat frying at 160$^{\circ}C$ for 8 min (DFF), and preheating Yackwa dough and then deep fat frying at 180$^{\circ}C$ for 2 min (MW/DFF). Soybean oil (SBO), hydrogenated soybean oil (HSBO) or hydrogenated palm oil (HPO) were used for frying Yackwa. Compared to Yackwa prepared by DFF, all MW/DFF Yackwa samples had low fat content and high moisture content. MW/DFF saved frying time 6 min compared with DFF. Non-hydrogenated soybean oil for frying fats was replaced with hydrogenated types of soybean oil and palm oil to improve the storage stability of Yackwa. To investigate the oxidation stability of Yackwa during the accelerated storage for 15 days at 60$^{\circ}C$, acid value, anisidine value, peroxide value and oxidation value of Yackwas were measured. Acid values of Yackwa made by MW/DFF were higher than those made by DFF through the whole storage periods, regardless of frying fats. Peroxide and anisidine values of Yackwa coated with syrup were much lower than those without syrup. MW/DFF cooking method, using hydrogenated soybean oil or hydrogenated palm oil for frying, showed lowering effects on peroxide value as well as anisidine value, resulting in improved oxidation stability of Yackwa during the storage. In sensory evaluation, the acceptability of MW/DFF Yackwa was higher than those of the commerical products. Yackwa prepared by MW/DFF cooking method using hydrogenated palm oil, showed the highest acceptability in color, taste and texture among the samples.

• Journal of Life Science
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• v.19 no.10
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• pp.1389-1395
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• 2009

Generally, it takes a long time to purify wood vinegar, and it contains toxic compounds such as tar, methanol, phenol and benzopyrene. To reduce the toxicity of wood vinegar itself, we have developed a new purification method of wood vinegar using an oxidation-cohesion reaction and distillation with an active carbon. We have investigated the physico-chemical change (pH, specific gravity, refractive index and dissolved tar), the change of amount of toxic compounds (carbonyl group, phenol, benzopyrene and residual solvents) and organic acids (formic acid (FA), acetic acid (AA), propionic acid (PA)) of the purified wood vinegar under the long term and accelerated storage conditions. Also, we have evaluated the effect of the purified wood vinegar on hair growth using an alopecia model of C57BL/6 mice. As a result, we could find out that the purified wood vinegar was stable and remained without decay under the storage conditions and benzopyrene, a carcinogenic agent, was not detected in the purified wood vinegar. After topical treatment of the purified wood vinegar solution or minoxidil (MXD) for 2 weeks to dorsal skin, the hair regrowth of the mice accelerated faster than that of the control, with no clinical signs. In conclusion, we could suggest a guideline for quality control of process to reduce the toxic compounds in wood vinegar and it might be a useful hair growth promoter in the treatment of baldness or alopecia.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.425-431
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• 2007

The quality characteristics of Gangjung added with detoxified Rhus verniciflua stem bark (RVSB) extract, as well as the changes that occurred in the product during accelerated storage ($60^{\circ}C$, 24 hr), were investigated. The expansion rate of Gangjung was not significantly different (p < 0.05). The L-value of the Gangjung with added detoxified RVSB extract was higher than the control, while the a-value decreased as the addition levels of the detoxified RVSB extract increased. The b-value was highest for the Gangjung prepared with 7% (w/w) detoxified RVSB extract. The moisture content of the Gangjung decreased as the storage period increased, but the addition of detoxified RVSB extract (p < 0.05) did not significantly change this effect. We found no significant difference in the hardness of the Gangjung within the concentration range of 0-7% (w/w) detoxified RVSB extract, and the peak number slightly decreased as the storage period increased. After 16 hr of storage, the acid value was significantly lower for the Gangjung containing detoxified RVSB extract at concentration between 5-7%. Furthermore, after 12 hr of accelerated storage, peroxide and TBA values significantly decreased with additions of detoxified RVSB extract that were over 3% (w/w). These results suggest that the physical texture of Gangjung did not improve by the addition of detoxified RVSB extract; however, its rate of lipid oxidation was reduced.