• Journal of Life Science
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• v.11 no.5
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• pp.457-463
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• 2001

A bacterial strain SC-22 which produced alkaline lipase was isolated from salf-fermented shrimps. Strains SC-22 was identified as Staphylococcus xylosus. An alkaline lipase excreted by Staphylococcus xylosus SC-22 was purified by ammonium sulfate predipitation and column chromatography on Sephadex G-100 and DEAE-Sephace. The specific activity of purified lipase was 756U/mg of protein with 17.2% yield. The approximate molecular weight of the purified enzyme was 47 kDa. The partially purified lipase preparation had and optimum temperature of 4$0^{\circ}C$, an optimum pH of 8.0, and a stable of 5~10. Lipase activities were enhanced by salt ions such as $Ca^{2+}$, $Mg^{2+}$,N $a^{2+}$ while inhibited remarkably by heavy metal ions, C $u^{2+}$ and P $b^{2+}$.EX> 2+/.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.1-19
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• 1973

Heavy metal concentrations have been determined in fishes and shellfishes sampled from October 1971 to April 1972 in Korea. In general, fish viscera, shellfish muscle and crustacean exoskeleton contained high concentrations of the metals. With regard to the regional variations of the metals, samples of the west coast of Korea contained relatively high concentrations of mercury, copper, cadmium and lead, but those of the south coast contained high levels of cadmium and lead. In particular, the concentrations of copper in the samples of the west coast were almost twice as much those of the other coasts. The concentrations of mercury in the samples, as a whole, ranged from 0.02 to 0.58 ppm with an average of 0.16 ppm. The concentrations of cadmium were higher in the fish viscera and shellfish than the fish muscle, ranging from less than 0.02 to 0.78 ppm with an average of 0.12 ppm in the fish and shellfish muscle samples. The lead concentrations were slightly high in the fish viscera. In the muscle and bone of fish and shellfish, the range was 0.06-4.84 ppm with an average of about 1 ppm. The concentrations of copper were very high in the viscera of fish and shellfish. The shellfish muscle contained almost four times as much copper as in the fish muscle, particularly cephalopods, i. e., squid and octopus, contained very high levels of copper, and oysters collected from Gunsan area on the west coast contained the highest levels of copper. The concentrations of copper ranged from 0.12 to 28.7 ppm with an average of 1.4 ppm in the fish muscle and of 5.9 ppm in the shellfish muscle.

• Korean Journal of Occupational Health Nursing
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• v.10 no.1
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• pp.55-65
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• 2001

The purpose of this study was to find out the status of occupational health management and the degree of recognition about the occupational health management of employees 248 small-scale enterprises which have been managed by the small-scale enterprises health care management support institution in 1999, were selected for study, in Kwang-Ju City. 98 employees were selected in 116 industries of them to grasp recognition of employees about the occupational health management. ► The Status of Occupational Health Management 1. Of the sample industries, 62.1 percent employed eleven to twenty-nine workers. Of the sample workers, 72.1 percent occupied workers who were engaged in the production line. 2. Environment evaluation was made on 82.7 percent of the sample industries and general exam made on 66.5 percent and specific health exam done on 73.4 percent. 3. The harmful factors in the sample industries were found to lie noise, dust, solvent, heavy metal, etc. 4. In general health exam 1,774 workers were participated and 148 workers got the result of above grade C and were diagnosed as having the problems with digestive system (63.6%), circulatory system(20.6%). etc. ► The Degree of Recognition about The Occupational Health Management of Employees. 1. Respondents were mainly in the twenties (42.9%), males(69.1%), duration of working period of five to ten years(24.0%), office workers(51.0%), monthly income under one million(55.7%). 2. Recognition of employees about the occupational health management consists of workplace environmental evaluation, health education, health exam and protector management. Their recognition on health education showed high score (mean 3.1), but generally the score was low(mean 2.9).

• Journal of the Korean Ceramic Society
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• v.32 no.11
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• pp.1269-1275
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• 1995

Effects of GeO2 addition on the thermal and structural stabilities of PbO-Bi2O3-Ga2O3 glasses were studied. Thermal stabilities, as assessed by the weighted thermal stability factors [(Tx-Tg)/Tg], increased with GeO2 concentraton from 0.097 to 0.210 with the addition of 20 mol% GeO2. Increasing GeO2 content resulted in the decrease of apparent density, molar volume, refractive index and thermal expansion. On the other hand, IR transmission cut-off (λT=50%) moved from 6.73${\mu}{\textrm}{m}$ for the ternary PbO-Bi2O3-Ga2O3 glass to shorter wavelength side, 5.98${\mu}{\textrm}{m}$ for a glass containing 20mol% GeO2. There were little change with GeO2 content, however, in the activation energies for the viscous flow of approximately 140 kcal/mole within the temperature interval of 300~50$0^{\circ}C$. Addition of GeO2 to PbO-Bi2O3-Ga2O3 glasses enhanced the thermal and structural stabilities significantly at the expense of their infrared transmittance. An appropriate compsomise between these two opposite trends should be made following the specifications of the final applications.

• The Korean Journal of Malacology
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• v.27 no.1
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• pp.77-86
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• 2011

The unwanted artificial oil-spill has severely contaminated the coastal environment in the world. Level of contamination has so far been monitered by various indicator species including mussel, oysters, flounder, and cockle. In this study, we decided to use the oyster as a model organism to observe the morphological changes being exposed to the artificial oil-spill in the coastal areas in Taean, Korea. The oysters were collected from four local sites (Sindu-ri, Uiwang-ri, Jonghyeon-dong, Ansan and Uihang-ri) exposed to various levels of pollution after an oil spill in Taean. Microscopic analysis of the hepatopancreatic microstructure in the digestive gland from the collected oysters show that the swelling, whorl, and destruction phenomenon of the nuclear membrane, a well-known microstructure induced by heavy metal exposure, was observed. Nuclear body (Nb), another typical characteristic of contamination or infection were also observed in some samples. Necrosis was observed in tissue samples collected from the area with a high degree of oil pollution. In addition, parasite-like particles (virus, perkinsus) were observed in most samples. Taken together, these results suggest that oil contamination in the oyster habitats influences the cytopathological changes in Crassostrea gigas.

• Polymer(Korea)
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• v.36 no.5
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• pp.573-578
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• 2012

In general, most physical properties of wood/polyvinyl chloride (PVC) composites are lower than those of corresponding neat PVC resin because of poor interfacial adhesion between the hydrophilic wood flour and hydrophobic PVC. Therefore, in this study, we treated wood flour with three aminosilanes to improve wood/PVC interfacial adhesion strength, and eco-friendly wood/PVC/nanoclay composites were prepared by melt blending the aminosilane-treated wood flour, a heavy metal free PVC compound, and a type of nanoclay. The effects of treating wood flour with the aminosilanes and adding the nanoclay on the mechanical properties of the composites were investigated. Mechanical properties of the composites were investigated by universal testing machine (UTM), izod impact tester, dynamic mechanical analyzer (DMA), and thermomechanical analyzer (TMA). The tensile properties of the composites with the aminosilane-treated wood flour were considerably higher than those of the composites with neat wood flour. Furthermore, a small amount of the nanoclay improved mechanical properties of the composites. The performance of the wood/PVC composites was considerably improved by using the aminosilane-treated wood flour and the nanoclay.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.380-387
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• 2015

A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as $^{235}U$, $^{239}Pu$, $^{241}Pu$, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux ($>10^{12}n/cm^2{\cdot}s$) neutron source comprised of a high-energy (30 MeV)/high-current (~2 A) electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (< $0.06{\mu}Sv/h$), a few shielding materials [high-density polyethylene (HDPE)eBorax, $B_4C$, and $Li_2CO_3$] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in the near future.

• Journal of Ginseng Research
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• v.30 no.3
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• pp.106-111
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• 2006

Adverse changes in individual's biochemistry under heavy metal stress are directly linked with its metabolic activity and health status. The present investigation highlights the differences in protecting role of Panax ginseng extract against mercuric chloride induced alterations in serum proteins. The assessment was based on dividing fifty albino rats into two sets, one for acute and the other for sub-acute study. All the sets had five groups with five albino rats in each i.e. control group, mercuric chloride treated group, Panax ginseng extract treated group, mercuric chloride followed by Panax ginseng extract treated group and Panax ginseng extract followed by mercuric chloride treated group. Mercuric chloride was given orally 0.926 mg/kg body weight for acute set and 0.044 mg/kg body weight for sub-acute set after LD50 (9.26 mg/kg body weight) determination by probitt analysis. 10 mg/kg body weight Panax ginseng extract was given in both acute and sub-acute sets after incorporating safety trials. The control group received tween-20 and distilled water only. The result exhibited significantly reduction (P<0.01) in serum protein, albumin and globulin following mercuric chloride intoxication whereas significant (P<0.01) enhancement in other groups with Panax ginseng extract as an ingredient confirming its protective role. All serum samples were also electrophoresed in 10% SDS with standard marker using discontinuous buffering system. Gradual disappearance of alpha-2 and beta-1 globulin bands from electrophoretic pattern was observed, while a single sharp band was observed between beta-2 and gamma globulin in serum protein pattern of acutely mercuric chloride treated rats. However, this band could not be visualized in sub-acute studies. Panax ginseng extract exhibits a better protection after acute intoxication.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.2
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• pp.153-170
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• 2013

This study examined awareness and information acquisition behavior regarding food hygiene and safety of university students to improve safe dietary practices and to get basic information to develop educational materials for food safety. It was conducted among 276 university students of Qingdao University and Liaocheng University in Shandong province, China through a self-administered questionnaire. Data were analyzed by SPSS Windows V.19.0. To describe characteristics of the respondents, frequency distributions were used. In addition, t test, one-way analysis of variance and Duncan's multiple range tests were conducted. The results were as follows: The respondents were generally interested in food hygiene and safety. However, the level of awareness regarding the food hygiene and safety system in China was not high. Almost forty-five percent of the respondents did not think that foods produced and distributed in China were safe. For the reasons for their distrust, most of the students replied that they did not trust the safety 'because of distrust for hygiene of the food process', followed by 'because of distrust for food distribution' and 'because of excess or illegal use of food additives on food process'. The respondents answered for the concern level toward food hygiene and safety foodborne disease threatened food safety the most, followed by heavy metal contamination and endocrine disruptors. The respondents acquired most information from electronic media including TV and radio. Most of the students wanted to participate in food hygiene and safety education. Finally, when they found hazardous or foreign materials in food the most frequent reaction was 'paying attention in the next purchase', followed by 'notifying others', and 'letting it go this time but never buying that product in the future'.

• Clean Technology
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• v.17 no.4
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• pp.353-362
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• 2011

In our nature, the utilization of rainwater is essential for healthy water recirculation. This is one of the solutions of the increment of impermeability surface according to the development of new cities; this study of the improvement of rainwater quality has been carried on through the improvement of collecting and restoring system of rainwater. The southwestern region of Daejeon City, the rainwater coefficient of run off was 0.40 and this number had computed to 0.59 after the development. After filtration of rainwater, the heavy metal (Cu, As, Cr, Fe, Mn) contents level were lower than underground water. Moreover, collected rainwater showed better quality than underground water in following criteria; hardness, permanganate consumption quality, chloride, evaporation residue, sulfates and nitrate nitrogen. This water quality met the gray water quality standards. The rainwater quality was still suitable to use as bathroom flushing and gardening after 100 days of storage. This study proved that modification (installation of cover with gutter to existing rainwater collection system, proper filtering, and installation of underground storage tank) of collection system could improve quality of water and maintain this approximately 100 days.