• Journal of Life Science
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• v.25 no.2
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• pp.237-242
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• 2015

The use of calcite-forming bacteria (CFB) in crack remediation and durability improvements in construction materials creates a permanent and environmentally-friendly material. Therefore, research into this type of application is stimulating interdisciplinary studies between microbiology and architectural engineering. However, the mechanisms giving rise to these materials are dependent on calcite precipitation by the metabolism of the CFB, which raises concerns about possible hazards to cement-based construction due to microbial metabolic acid production. The aim of this study was to determine target microorganisms that possibly can have bio-corrosive effects on cement mortar and to assess multi-functional CFBs for their safe application to cement structures. The chalky test was first used to evaluate the $CaCO_3$ solubilization feature of construction sites by fungi, yeast, bacterial strains. Not all bacterial strains are able to solubilize $CaCO_3$, but C. sphaerospermum KNUC253 or P. prolifica KNUC263 showed $CaCO_3$ solubilization activity. Therefore, these two strains were identified as target microorganisms that require control in cement structures. The registered patented strains Bacillus aryabhatti KNUC205, Arthrobacter nicotianae KNUC2100, B. thuringiensis KNUC2103 and Stenotrophomonas maltophilia KNUC2106, reported as multifunctional CFB (fungal growth inhibition, crack remediation, and water permeability reduction of cement surfaces) and isolated from Dokdo or construction site were unable to solubilize $CaCO_3$. Notably, B. aryabhatti KNUC205 and A. nicotianae KNUC2100 could not hydrolyze cellulose or protein, which can be the major constituent macromolecules of internal materials for buildings. These results show that several reported multi-functional CFB can be applied to cement structures or diverse building environments without corrosive or bio-deteriorative risks.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.1-10
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• 2016

Obesity is a pro-inflammatory state that contributes to the development of metabolic disorders such as hyperlipidemia, insulin resistance, type 2 diabetes, non-alcoholic fatty liver, and cardiovascular disease. In this study, we evaluated the inhibition of adipogenesis in 3T3-L1 cells and in high-fat diet (HFD)-induced obese mice by Peucedanum japonicum Thunberg L. water extract (PJT). Lipid accumulation measurement indicates that PJT markedly inhibited adipogenesis in a dose-dependent manner. RT-PCR results demonstrated that the mRNA expression of adipogenic transcription factors such as peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer binding protein-α (C/EBPα) in 3T3-L1 cells were significantly down-regulated by PJT treatment. Oral administration of PJT (100, 300, and 500 ㎎/㎏, b.w/daily for 4 weeks) was conducted in high-fat diet induced obese mice and C57BL/6 mice. The PJT-administered group of HFD-induced mice had a lower body weight gain, along with decreased serum levels of glucose, triglycerides, and total cholesterol compared with the control mice, however, the HDL-cholesterol/total cholesterol ratio was increased. Furthermore, the elevated mRNA expression levels of adipogenesis related genes in the white adipose tissue of obese mice were significantly suppressed by PJT. These results indicate that PJT exhibits anti-obesity effects in obese mice by decreasing in serum lipid levels and lipogenesis related gene.

• The Korean Journal of Food And Nutrition
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• v.14 no.1
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• pp.34-39
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• 2001

The purpose of this study was to examine physical properties of the addition of green tea powder on bread flour and dough rheology of white pan bread. Three levels(0.1, 0.5 and 1.0% ) of each green tea powder with bread flour were tested for their effects in dough mixing using rapid disco analyzer, alveogram and farinogram. Addition of green tea powder tended to reduce initial pasting temperature and increase peak viscosity, break down and set back. L(extensibility) and G(swelling index) value in alveogram showed decrement with increasing green tea powder. These meant that the volume of white pan bread would show same tendency. The use of green tea powder increased consistency and water absorption of the bread flour but decreased development time, salability and degree of softening on farinogram. White pan bread with green tea powder had higher value of hardness and springness than without it. Sensory evaluation determined that the white pan bread with 0.5% green tea powder had the highest score.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.567-587
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• 2018

A severe haze event occurred in October 2015 in Gwangju, Korea. In this study, the driving chemical species and the formation mechanisms of $PM_{2.5}$ pollution were investigated to better understand the haze event. Hourly concentrations of $PM_{2.5}$, organic and elemental carbon, water-soluble ions, and elemental constituents were measured at the air quality intensive monitoring station in Gwangju. The haze event occurred was attributed to a significant contribution (72.3%) of secondary inorganic species concentration to the $PM_{2.5}$, along with the contribution of organic aerosols that were strongly attributed to traffic emissions over the study site. MODIS images, weather charts, and air mass backward trajectories supported the significant impact of long-range transportation (LTP) of aerosol particles from northeastern China on haze formation over Gwangju in October 2015. The driving factor for the haze formation was stagnant atmospheric flows around the Korean peninsula, and high relative humidity (RH) promoted the haze formation at the site. Under the high RH conditions, $SO{_4}^{2-}$ and $NO_3{^-}$ were mainly produced through the heterogenous aqueous-phase reactions of $SO_2$ and $NO_2$, respectively. Moreover, hourly $O_3$ concentration during the study period was highly elevated, with hourly peaks ranging from 79 to 95ppb, suggesting that photochemical reaction was a possible formation process of secondary aerosols. Over the $PM_{2.5}$ pollution, behavior and formation of secondary ionic species varied with the difference in the impact of LTP. Prior to October 19 when the influence of LTP was low, increasing rate in $NO_3{^-}$ was greater than that in $NO_2$, but both $SO_2$ and $SO{_4}^{2-}$ had similar increasing rates. While, after October 20 when the impact of haze by LTP was significant, $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations increased significantly more than their gaseous precursors, but with greater increasing rate of $NO_3{^-}$. These results suggest the enhanced secondary transformation of $SO_2$ and $NO_2$ during the haze event. Overall, the result from the study suggests that control of anthropogenic combustion sources including vehicle emissions is needed to reduce the high levels of nitrogen oxide and $NO_3{^-}$ and the high $PM_{2.5}$ pollution occurred over fall season in Gwangju.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.496-504
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• 1997

This study was carried out to estimate toxic effects of phenol on survival and metabolism of the abalone juvenile, Haliotis discus hannai. The experiment was conducted by renewal bioassay procedure with different salinities at $20^{\circ}C$. The $LC_{50}$ of the juvenile exposed to phenol in the range of 0.5 and $100mg/\ell\;was\;34.3\~6.5mg/\ell\;at\;2.4\%_{\circ}\;and\;52.2\~9.3m/\ell\;at\;32\%_{\circ}$ salinity with exposure time from 24 hours to 96 hours. $LT_{50}$ was remarkablely reduced with increase of phenol conentration and decrease of salinity. Lethal toxicity or phenol was higher at low salinity than at high salinity. Therefore, salinity is likely to be one of factor to increase phenol toxicity. The oxygen consumption of the juvenile was reduced with increase of phenol concentration and with decrease of salinity. In spite of phenol toxicity, the oxygen consumption of the juvenile exposed to phenol of low concentration was high and similar as compared with that of control group. Survival rates of the abalone kept in phenol-free sea water after exposure to phenol concentration of 5, 10 and $20mg/\ell$ for 96 hours were reduced with decrease of salinity. Durations required to recover the normal metabolic rate of the juvenile, which was exposed to phenol concentration of 5, 10 and $20mg/\ell$ for 96 hours, were made longer with increasing phenol concentration. In the case of the juvenile exposed to sublethal concentration of phenol for 15 days, it were elongated as compared with that of the abalone exposed to phenol concentration caused acute toxicity. The result of this experiment indicated that relatively low concentration of phenol can impact on the abalone juvenile in marine ecosystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.417-423
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• 2002

The edible films were prepared from the protein of alaska pollack, Theragra chalcogrmma. Effects of plasticizer, cross linker and laminated film on physical properties such as tensile strength (TS), elongation (E) and water vapor permeability (WVP) of films were investigated. In adding various kinds of plasticizers, TS of the films prepared with propylene glycol (PG) was the highest, and followed sorbitol, polyethylene glycol 200 (PEG 200) and glycerol. Elongation of the films prepared with glycerol was the highest, then sorbitol, PEG 200 and PG. WVP of films showed lower in order of PG, sorbitol, glycerol and PEG 200.75 decreased with the increment of plasticizer concentration, but elongation increased, The addition of both PG and PEG 200 effected weakly on elongation, so they were inadequate as plasticizer for the film. Mixtures of glycerol and sorbitol, which showed opposing both TS and elongation in the films, could control the physical properties of the films. With increasing relative humidity, TS decreased, while elongation and equilibrium moisture content increased. By adding the cross linkers such as ascorbic acid, citric acid and succinic acid, TS and m of films increased, while elongation decreased. Ascorbic acid, citric acid, succinic acid were most effective for TS at 0.2, 0.1 and $0.1\%, respectively. Laminated film with alaska pollack protein and corn zein improved TS above two times, reduced WVP about $20\~30\%$, as compared with the Elm from alaska pollack protein. Two films did not show the difference to oxygen permeability, but they showed about tenfold greater oxygen resistance than polyethylene film. Laminated film showed higher b and $\Delta$E value of color difference, lower a and L value than the film from alaska pollack protein.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.177-183
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• 2008

It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel, undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesiodistally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference in fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even if that portion consists of mainly enamel and a little dentin structure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1219-1225
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• 2005

This study was carried out to investigate the effects of preheating temperature on the properties of the Korean traditional pepper pickle. In experimental groups, the pepper was heated in the warm water at 40, 60, 80$^{\circ}C$ for 10 minutes while the control group was not heated. The contents of chlorophyll and vitamin C in treated pepper were evaluated. The contents of chlorophyll were 30.96$\∼$31.13 mg$\%$ at the initial stage of 0 day and 0.76$\∼$2.34 mg$\%$ for 60 days of storage. The vitamin C contents were increased until storage 6 days and then were decreased. Pickles treated at 60$^{\circ}C$ showed the highest score on hardness after 60 days of storage followed by 40$^{\circ}C$>no-heat treatment (NH)>80$^{\circ}C$. The yellowness on the surface of brined pepper peels was increased with preheating temperature increased. Activities of pectinesterase were the highest at 60$^{\circ}C$ followed by 40$^{\circ}C$>80$^{\circ}C$>NH treated. Activities of polygalacturonase were lower than that of NH group.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.27-32
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• 1984

Recently, it has been reported that acute and chronic intoxication of Cd was concerned with environmental hygienic studies. In this study the effect of Ca and V-D was given directly into the diet with water containing the 20 ppm of Cd during so days. The results obtained were summarized as follows; 1. Administration of Ca and V-D inhibited the reduction of body weight induced by Cd. The internal organ weights of rats receiving Cd solution without Ca and V-D were generally increased except lung. 2. The values of hematocrit were higher in rats receiving Cd solution supplemented Ca and V-D than those doing Cd solution without Ca and V-D, and the levels of cholesterol were in- creased in experimental rats compared with control group. Total protein concentration in serum of the both group intaking the Ca and Y-D, and without Ca and V-D was not significant. 3. The concentration of Cd and Mg in liver was increased in rats feeding only Cd solution than those doing Ca and V-D group, whereas the concentration of Cu, Zn and Ca was decreased. The concentration of Cd, Cu and Ca in kidney was decreased in only Cd solution group, whereas by supplementing Ca and vitamin D was increased the concentration of Cd, Cu and Zn.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.426-434
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• 2011

In order to increase the use of rice, ginseng Garaedduks and Topokki were made and the physicochemical and sensory properties were investigated. Topokki and Garaedduks were added with 0, 1, 3 and 5% ginseng powder and stored at $20^{\circ}C$ for 48 hours. The moisture contents were not different to the increasing amount of ginseng powder and increasing storage time for 48 hours. The moisture content of Garaedduks for control and 5% added ginseng powder were 48.08% and 49.62%, respectively. The L value in color of uncooked ginseng Garaedduk decreased according to the added amount of ginseng powder, and the b value in color increased significantly according to the added amount of ginseng powder and during 48 hours storage at $20^{\circ}C$. Textural analysis, measured using a texture analyzer, of Garaedduk revealed that hardness, cohesiveness, chewiness decreased significantly and adhesiveness increased according to the added amount of ginseng powder. In sensory evaluation, 5% ginseng Garaedduk (uncooked, cooked) scored higher in overall acceptability than those of the other samples. In cooking properties, water absorption and solid contents increased according to the added amount of ginseng powder. Therefore, Garaedduk containing 5% ginseng powder was the most preferable. These results implied that the degree of retrogradation of ginseng Garaedduk might be low due to its high dietary fiber content.