• Advances in environmental research
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• v.2 no.3
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• pp.229-243
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• 2013

Coagulation-flocculation (CF) was tested coupled with an aerobic biofilter to reduce total petroleum hydrocarbon (TPHs) concentration and toxicity from petrochemical wastewater. The efficiency of the process was followed using turbidity and chemical oxygen demand (COD). The biofilter was packed with a basaltic waste (tezontle) and inoculated with a bacterial consortium. Toxicity test were carried out using Lactuca sativa var. capitata seeds. Best results for turbidity removal were obtained using alum. Considerable turbidity removal was obtained when using Opuntia spp. COD removal with alum was 25%, for Opuntia powder it was 36%. The application of the biofilter allowed the removal of 70% of the remaining TPHs after 30 days with a biodegradation rate (BDR) value 47 $mgL^{-1}d^{-1}$. COD removal was slightly higher with BDR value 63 $mgL^{-1}d^{-1}$. TPH kinetics allowed a degradation rate constant equal to $4.05{\times}10^{-2}d^{-1}$. COD removal showed similar trend with $k=4.23{\times}10^{-2}d^{-1}$. Toxicity reduction was also successfully achieved by the combined treatment process.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.169-176
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• 2013

Objectives: The aim of this study is to critically review the health effects of not only direct exposure to biocide, but also indirect exposure to by-product hazardous agents generated through the use of biocide in metalworking operations. Methods: An extensive literature review was conducted of studies reporting on respiratory disease cases, particularly hypersensitivity pneumonitis (HP), in environments using water-soluble metalworking fluids (MWFs). Keyword search terms included 'metalworking fluids', 'machining fluids', 'metalworking operation' 'machining operation' and 'biocide', which were also used in combination. Additional articles were identified in references cited in the articles reviewed. Results: Several of the field, epidemiological and experimental studies reviewed assumed that the symptoms and signs typical of HP developed in machinists who handled water-soluble MWF could be caused by inhalation exposure to nontuberculous mycobacteria (NTM). Most NTM are known to be not only resistant to both biocide and disinfectant, but also to have acid-fast cell walls that are highly antigenic. The presence or persistence of the Mycobacterium species, referred to as NTM, in metalworking fluid-using operations may be caused by NTM contamination in either the natural water or tap water that is used to dilute the base oil and additives for water-soluble MWFs. This hypothesis that NTM contamination in water-soluble MWFs is a causative agent of HP has high biologic plausibility, such as antigenic property, hydrophobicity and small diameter (< 5 um). Conclusions: Aerosolized mycobacteria colonized from MWF are likely to be causing the HP. Inhalation exposure to mycobacteria should be considered as a possible cause for the development of HP.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.349-360
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• 2011

The international oil price have being fluctuated due to the exhaustion of fossil energy problem became big social issue. Rural villages are relatively sensitive to the energy problem, reflecting the characteristics of rural sustainable and stable introduction of renewable energy sources that are available is essential. In addition, through the influx of young workers in rural areas to regain vitality, efforts to improve rural living environment has been under the rural newtown project. In this study, a survey aimed at rural dwellers through the AHP, interview to report of realization about renewable energy and review the current policies. The results of realization survey though AHP are as follows, (1) the advantage of the natural environment (2) the superiority of government supporting policy and being economic, (3) easy to use, (4) ecologically stable, and (5) policy stable, respectively. In addition, renewable energy sources among the inhabitants of rural areas by solar energy was the highest score. The impact of regional characteristics compared with other energy sources receive little, easy to apply and has already been considerable technological development is considered.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.68
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• pp.123-148
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• 2015

Central Asian Countries had been independent in 1991 from USSR. Since then it have been increasing foreign trade and investment amount with outside countries including China, Japan, EU and South Korea. Korean enterprises and entities have endeavored to secure plentiful natural resources, oil and gas energy and expand the market share to exporting the consuming and industrial competitive goods and services for those countries. In the case of disputes of commercial transactions and investment, arbitration is regarded as a dispute resolution system which has been preferred in international transactions and investments by the business world. Since the collapse of the USSR, Central Asian Countries have worked to modernize its arbitration law and procedure to conform with international standard rules. Arbitral legislation in Central Asian countries is based on the Model Law as adopted in 1985. However, CIS's legislation systems of arbitration are not satisfied with the international standard in national laws and practices. That is the reason to consider for the specific parliament about arbitration for the dispute resolutions in the commercial transaction and investment between Korean enterprises and CIS. In this article, it is discuss problems and its alternatives in the dispute resolution about the commercial transaction and investment into Central Asian countries including the tendency to the increasing the trade volumes of goods and investment between South Korea and CIS. According to this article, South Korea consider the long term strategy followed the preferred economic relative partnership for business success on commercial transaction and investment with the Central Asian Countries.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.spc1
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• pp.123-144
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• 1996

This review deals briefly with the various medicinal components(mainly saikosaponins), their biological activities and the variation of their contents by different cultivation environment and plant parts in Bupleurum species. Bupleuri radix, a crude drug, is the root of Bupleurum falcatum L. (Korea, Japan), B. chinense(China), and their related species (Umbelliferae). There are over 120 species in Bupleurum genus throughout world, mainly Asian area, and over 5 species in Korea, investigated up to now. These plants contain many physiological active compounds and the principal components are saikosaponins. Major activities of this crude drug and saikosaponins are the anti-inflammatory and antihepatotoxic activities. Saikosaponins and their derivatives in Bupleurum spp. have been chemically studied, isolated and identified over 70 compounds in over 50 species. Other components, physiologically active ones, also have been investigated, which are the groups of lignan, flavonoid, essential oil, polyacetylene, polysaccharide, etc. Saikosaponins belong to the group of triterpenoid saponin chemotaxonomically and occur the accumulation and turnover in plant tissues through secondary metabolism, mevalonic acid pathway. The contents and kinds of saikosaponins and other components in Bupleurum spp. plants are various due to different species and growing environments, as the plant growth characters and yield are various. Most of medicinal plants as well as Bupleurum species are very useful as agricultural products and traditional medicines, and also are very valuable as genetic resources and natural products. So we need to collect, evaluate, preserve, and utilize various medicinal plants, and also to under-stand secondary metabolism and improve the breeding and cultivation techniques for the safe production of crude drugs with high quality and yielding.

• Food Science and Preservation
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• v.9 no.3
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• pp.345-350
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• 2002

This study was carried out to determine the effect of gamma irradiated Puerariae radix extract on color removal, antioxidative, DPPH radical scavenging and antimicrobial efftcts. Puerariae radix were extracted with methanol and acetone and irrdiated 10, 20 and 30 kGy with gamma ray. Hunter color L-value increased by irrdiation in a dose dependent manner, resulting in brighter color. But a and b values decreased by irradiation in a dose dependent manner. Antioxidant activities of the Puerariae radix extract in soybean oil emulsion were higher in methanol extract than acetone extract. Scavenging effect of Puerariae radix extracts on DPPH radical with methanol was not changed by irradiation but acetone decreased Acetone extract from Puerariae radix showed antimicrobial activities in B. subtilis, B, natto, B, megaterium S, aureus, Sal, typhymurium and E. coli methanol extract also had the antimicrobial activities but weaker for Sal. typhymurium and E. coli. Results suggested that Puerariae radix extracts have a potential as a natural food preservatives and cosmetic raw material.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.65-71
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• 2009

Hydraulic fracturing technology has been widely applied in the industry for the recovery of the natural resources such as gas, oil and geothermal heat from hot dry rock. During hydraulic fracturing stimulation, multiple cracks are created resulting in mechanical interaction between cracks. Such an interaction influences obtaining hydraulic fracturing key parameters (crack opening, length, and borehole net pressure). The boundary collocation method (BCM) has been proved to be very effective in considering mechanical interaction. However, for better confidence, it needs to be verified by comparison with analytical solutions such as stress intensity factors. In this paper, three cases, single fracture in remote uniaxial tension, single fracture in remote shear stress field and two arbitrary segments in an infinite plane loaded at infinity are considered. As a result, the BCM is proved to be valid technique to consider mechanical interaction between cracks and can be used to estimate the hydraulic fracturing parameters such as opening of the fracture, and so on.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.135-141
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• 2001

Recently, the consumption of soy products has been associated with low rates of hormone-dependent and hormone-independent cancers. Asians, who consume $20{\sim}50times$ more soy per capita than Americans, have lower incidence and death rates from breast and prostate cancer. Because soy contains the isoflavones genistein and daidzein (present as their glycosidic conjugates) at mg/g concentrations, it has been suggested that isoflavones might be acting as natural chemopreventive agents. During the 1980s several groups of investigators carried out experiments to test the effectiveness of soy in the diet in animal models of cancer. These studies reported a protective effect of soy; none showed that soy increased cancer risk. Genistein was shown to inhibit the growth of a wide variety of tumor cell types in culture. The purpose of this study was to evaluate the effects of genistein on the carcinogenesis induced by topical application of 0.5% 9, 10-dimethyl 1,2-benzanthracene (DMBA) on the hamster buccal pouch. 48 syrian hamsters were employed in this study, divided into experimental group and control. 24 animals (DMBA topical application group) had the right buccal pouch painted 3times weekly with 0.5% DMBA in mineral oil, 24 animals (genistein group) were supplied with 0.1mg genistein with DMBA topical application. 3 animals in the experimental group and control were sacrificed at serially each other week after experiments. Their buccal pouches were removed and routinely processed for microscopic examination. The results were as follows: 1. In DMBA topical application and genistein group, they showed carcinogenesis as time goes by experimental stage. 2. Genistein group was retarded in carcinogenesis related to the acanthosis, hyperkeratosis, epithelial dysplasia. 3. p53 immunohistochemical study showed that the p53 protein of genistein group was less expressed than that of the control group. Thus, it seems that genistein has chemopreventive effect on the carcinogenesis in the oral cavity, but further study is required to elucidate the anticancer mechanism of genistein.

• Journal of Energy Engineering
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• v.12 no.4
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• pp.320-327
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• 2003

A CFD (Computational fluid Dynamics) research is conducted for the investigation of the fuel alteration of MBTU (medium-Btu) gas in IGCC gas turbine combustor. The computational analysis method of the gas turbine combustor is constructed by incorporating MBTU gas reaction and fuel NOx models into commercial CFD code. With the use of the present analysis method, comparisons are made on the flow velocity, the chemical species and the temperature distributions, and on the flame shape and behavior of gas turbine combustor firing natural gas and MBTU gases (coal gas, heavy residue oil gas). Furthermore, the NOx formation characteristics and the turbine matching condition of the combustor are analyzed. Based on the computed analysis results, the present study provides the directions for the redesign and the design modification of IGCC gas turbine combustor firing MBTU gas as alternative fuel.

• Korean journal of food and cookery science
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• v.18 no.4
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• pp.407-412
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• 2002

The purpose of this study was to investigate the oxidative stability of green tea-added mayonnaise during storage at 5, 15 and 25$\^{C}$. Mayonnaise was prepared with salad oil, egg yolk, sugar, salt and vinegar, and added with 0.1, 0.3 and 0.5% of green tea powder for experiment. Peroxide values (POV) of each mayonnaise were compared during storage for 13 weeks. POVs of control mayonnaise stored at 5, 15 and 25$\^{C}$ for 13 weeks were 28.0, 63.5 and 144.4 meq/kg, respectively. Oxidative stability of green tea-added mayonnaise was increased with increasing concentration of green tea in mayonnaise, but it was decreased with increasing storage temperature. The addition of green tea at 0.5% extended the induction period of mayonnaise significantly (p<0.05) at each temperature. Relative antioxidant effect (RAE) of mayonnaise containing 0.1% of green tea were 226%, 188% and 143% during storage at 5, 15 and 25$\^{C}$, respectively, and it was increased with increasing green tea concentration in mayonnaise. The results suggested that the use of green tea is valuable to inhibit the oxidation of mayonnaise as a natural antioxidant.