• Journal of Conservation Science
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• v.26 no.1
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• pp.61-67
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• 2010

After selecting five types of adhesive epoxy resin for metallic cultural assets such as $Araldite^{(R)}$ rapid type, $Devcon^{(R)}$, $Araldite^{(R)}$ SV427+HV427, $CDK^{(R)}$520, $Araldite^{(R)}$ AW106+HV953 which had already been studied, this paper approached more closely the problem of yellowing and the signal of aging with time passing by connecting the problems with the safety of metallic cultural assets. The change of physical properties according to the change of state of epoxy adhesives was investigated through the change of flexural strength and the change of surface hardness by artificially providing the possible environmental change factors such as ultra-violet ray, and acid base, and how the epoxy chemically changes in its ingredients by the environment was analyzed through FT-IR. As a result of the experiment, for the most part of adhesives brought about the physical change of flexural strength, the change of surface hardness, and the chemical change of chemical ingredients as the product of alcohol, which were respectively different according to the time of ultraviolet irradiation, and acid base change. Under most of the conditions, SV427+HV427 and $CDK^{(R)}$520 were fairly stabilized under each condition of weatherability, but it seems that they should be refrained from being applied in case that the area to restore is thin and wide because the degree of flexural strength of themselves is low. Also, it is found that the preservation environment is very important not only for artifacts but also for the preservation of resins sused for preservation treatment.

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.279-288
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• 1986

One hundred and fifty one mutant strains were obtained from the parent strain Aspergillus oryzae MF by ultra-violet ray irradiation. Among those mutants a strain, Asp. oryzae UM-36 which hyperprodued protease, was selected and its morphological characteristics and the production of enzymes protease, ${\alpha}$-amylase, and glucoamylase on wheat bran koji and on soy-sauce koji were studied. The results obtained were as follows 1. The selected mutant showed slower growth and weak sporulation on malt agar and on Czapek agar than the parent strain. 2. The conidiophores of the mutant were generally shorter than those of the parent when grown on malt agar. 3. Sectoring in colonies was not found when grown on malt agar and on Czapek agar. 4. The level of protease production by the mutant was increased approximately 1,4-fold higher on wheat bran koji and 2-fold higher on soysauce koji than by the parent. 5. The production of ${\alpha}$-amylase and glucoamylase by the mutant were also increased as compared with the parent on wheat bran koji and on soy sauce koji. 6. In the case of parent strain and mutant strain, the highest activity of protease appeared after three days in wheat bran medium at $30^{\circ}C$ incubation, but the highest activities of ${\alpha}$-amylase and glucoamylase appeared after two days.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.355-360
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• 1997

In order to investigate the influence of photosensitized oxidation in the sun-dried irish moss (Chondrus Ocellatus), laver (Porphyra Yezoensis) and ultra violet irradiated oyster (Crassostrea gigas) the oxidation of lipid and isomers of hydroperoxides were analyzed by gas chromatography-mass spectrometry. The lipid contents of oyster, irish moss and layer were $2.7\%,\;0.1\%,\;0.1\%$ of respectively. Peroxide value, 56,7 meq/kg in the raw oyster was increased of 100.9 meq/kg by the U.V, irradiation for 4 hours. Also the peroxide values of the irish moss and laver were increased by the sun-drying. In the identification of hydroperoxides isomers by trimethylsily (TMS) derivative of photo-oxidized lipid from oyster, irish moss and laver, the proportions of positional isomer, 9-OOH and 13-OOH were dominant than those 10-OOH and 12-OOH.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.929-935
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• 2014

Two types of nanosized titanium dioxide, anatase ($anTiO_2$) and rutile ($rnTiO_2$), are widely used in industry, commercial products and biosystems. $TiO_2$ has been evaluated as a Group 2B carcinogen. Previous reports indicated that $anTiO_2$ is less toxic than $rnTiO_2$, however, under ultraviolet irradiation $anTiO_2$ is more toxic than $rnTiO_2$ in vitro because of differences in their crystal structures. In the present study, we compared the in vivo and in vitro toxic effects induced by $anTiO_2$ and $rnTiO_2$. Female SD rats were treated with $500{\mu}g/ml$ of $anTiO_2$ or $rnTiO_2$ suspensions by intra-pulmonary spraying 8 times over a two week period. In the lung, treatment with $anTiO_2$ or $rnTiO_2$ increased alveolar macrophage numbers and levels of 8-hydroxydeoxyguanosine (8-OHdG); these increases tended to be lower in the $anTiO_2$ treated group compared to the $rnTiO_2$ treated group. Expression of $MIP1{\alpha}$ mRNA and protein in lung tissues treated with $anTiO_2$ and $rnTiO_2$ was also significantly up-regulated, with $MIP1{\alpha}$ mRNA and protein expression significantly lower in the $anTiO_2$ group than in the $rnTiO_2$ group. In cell culture of primary alveolar macrophages (PAM) treated with $anTiO_2$ and $rnTiO_2$, expression of $MIP1{\alpha}$ mRNA in the PAM and protein in the culture media was significantly higher than in control cultures. Similarly to the in vivo results, $MIP1{\alpha}$ mRNA and protein expression was significantly lower in the $anTiO_2$ treated cultures compared to the $rnTiO_2$ treated cultures. Furthermore, conditioned cell culture media from PAM cultures treated with $anTiO_2$ had less effect on A549 cell proliferation compared to conditioned media from cultures treated with $rnTiO_2$. However, no significant difference was found in the toxicological effects on cell viability of ultra violet irradiated $anTiO_2$ and $rnTiO_2$. In conclusion, our results indicate that $anTiO_2$ is less potent in induction of alveolar macrophage infiltration, 8-OHdG and $MIP1{\alpha}$ expression in the lung, and growth stimulation of A549 cells in vitro than $rnTiO_2$.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.69-75
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• 2006

Improper disposal of petroleum and spills from underground storage tanks have created large areas with highly toxic contamination of the soil and groundwater. Methyl tert-butyl ether (MTBE) is widely used as a fuel additive because of its advantageous properties of increasing the octane value and reducing carbon monoxide and hydrocarbon exhausts. However, MTBE is categorized as a possible human carcinogen. This research investigated the Modified Photo-Fenton system which is based on the Modified Fenton reaction and UV light irradiation. The Modified Fenton reaction is effective for MTBE degradation near a neutral pH, using the ferric ion complex composed of a ferric ion and environmentally friendly organic chelating agents. This research was intended to treat high concentrations of MTBE; thus, 1,000 mg/L MTBE was chosen. The objectives of this research are to find the optimal reaction conditions and to elucidate the kinetic and mechanism of MTBE degradation by the Modified Photo-Fenton reaction. Based on the results of experiments, citrate was chosen among eight chelating agents as the candidate for the Modified Photo-Fenton reaction because it has a relatively higher final pH and MTBE removal efficiency than the others, and it has a relatively low toxicity and is rapidly biodegradable. MTBE degradation was found to follow pseudo-first-order kinetics. Under the optimum conditions, [$Fe^{3+}$] : [Citrate] = 1 mM: 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, and initial pH 6.0, the 1000 ppm MTBE was degraded by 86.75% within 6 hours and 99.99% within 16 hours. The final pH value was 6.02. The degradation mechanism of MTBE by the Modified Photo-Fenton Reaction included two diverse pathways and tert-butyl formate (TBF) was identified to be the major degradation intermediate. Attributed to the high solubility, stability, and reactivity of the ferric-citrate complexes in the near neutral condition, this Modified Photo-Fenton reaction is a promising treatment process for high concentrations of MTBE under or near a neutral pH.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.465-474
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• 1999

RNase activity of Saccharomyces cerevisiae ATCC 7754 was investigated to obtain strains with high ribonucleic acid (RNA) content. The yeast strain contained two RNase activities; an acidic RNase with a optima of pH $3{\sim}4$ and an alkaline RNase with a optima pH 9. The acidic RNase activity was inhibited by $0.08\;M\;HgCl_{2}$ most drastically. The alkaline RNase activity was inhibited by 2.0 M NaCl or KCl, while enhanced by addition of $0.05\;M\;CaCl_{2},\;0.02\;M\;ZnSO_{4},\;or\;0.008\;M\;HgCl_{2}$. Various mutants of Saccharomyces cerevisiae ATCC 7754 were isolated by ethylmethane sulfonate (EMS) treatment or $\gamma$-ray/ultra violet irradiation. Among the mutants that were sensitive to high concentration of KCl which inhibits alkaline RNase, B24 was selected for high RNA content per culture volume. Growth characteristics of the mutant were comparable to those of the mother strain with optimum growth at pH $4.5{\sim}5.5$. The mutant accumulated higher content of RNA than the mother strain when glucose was used as the carbon source. However, both growth rate and total RNA content of the mutant were higher in molasses medium than in glucose medium. RNA content of the mutant increased rapidly during the early stage of growth, and then decreased gradually until the culture reached stationary phase by a fed-batch culture in a 5 L jar fermenter. Maximal cell harvest and the final RNA content using the mutant B24 were 69.6 g/L culture broth and 19.8 g/100 g of the dry cell while those using the mother strain were 68 g/L culture broth and 16.1 g/100 g of dry cell, respectively.