• Korean Journal of Pharmacognosy
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• v.32 no.4 s.127
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• pp.311-315
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• 2001

The root of Astragalus membranaceus Bunge (Leguminosae), which has been used for the treatment of hypertension, chronic hepatitis, duodenal ulcers, chronic nephritis and promotion of immunity in folk remedies. Cyclooxygenase (COX-2) is responsible for the production of large amounts of proinflammatory prostaglandins (PGs) at the inflammatory site. Thus, a logical approach to the treatment of inflammatory disease should involve the inhibitors of COX-2. To develop new COX-2 inhibitors from natural products, Astragali Radix was screened by inhibiting prostaglandin $E_2(PGE_2)$ generation in the culture medium using enzyme immunometric assay. Two isoflavone glycosides, $7,2'-dihydroxy-3',4'-dimethoxyisoflavan-7-O-{\beta}-D-glucoside$ and $calycosin-7-O-{\beta}-D-glucoside$ isolated from Astragali Radix inhibited COX-2 activity.

• Asian Journal of Atmospheric Environment
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• v.5 no.3
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• pp.172-180
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• 2011

The transfer of microorganisms is important process for ecosystems. Microorganisms in dryland can transport itself to wetland through atmospheric diffusion, but only few papers reported about the atmospheric bioaerosol present over dryland. We carried out the direct sampling using a tethered balloon over Dunhuang City, China's northwestern dryland. Bioaerosols were collected using a tethered balloon with a bioaerosol collector at 820 m above the ground (1,960 m above the sea level) around noon on August 17, 2007. The bioaerosols were cultured after the collection at Dunhuang Meteorological observatory. Two strains of molds were isolated using the Nutrient agar medium. About 400-bp 18S rRNA partial sequences were amplified by PCR and determined afterwards. The results of a homology search by 18S rRNA sequences of isolates in DNA databases (GenBank, DDBJ, and EMBL) and an observation of the form revealed that two bioaerosols in the convective mixed layer over Dunhuang City were Cladosporium sp. and Aspergillus sp.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.91-95
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• 1999

The Streptomyces albulus broth, when the polylysine in the broth, that has powerful growth inhibiting effect far many microbes, is its maximum, had filtered off the cells, to use the broth as preservative for keeping favorable taste of Korean Kimchi. Some microorganisms in their specific growth medium, known to deteriorate the useful nutrient of the Kimchi, has grown with different amounts of the inhibiting broth, to determine the minimum growth inhibition concentration. The ${\varepsilon}$-poly-L-lysine had been identified from the IR spectroscopic analysis of the purified poly lysine of the broth from ion exchange chromatographic separation. The content of the polylysine had been determined by methyl orange decoloration effect. Though the minimum inhibition concentration, evaluated by the naked eye based on the conventional method measuring the turbid feature after 18 hours of culture, has different values each other, the observed effects confirmed that the crude broth could be used as a natural preservative for the Kimchi in extending the fair taste.

• Smart Structures and Systems
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• v.22 no.1
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• pp.71-79
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• 2018

The nonlinear vibration analysis of a magneto-rheological elastomer (MRE) sandwich plate is conducted experimentally. Experiments have been performed in order to construct the frequency-response curves in the vicinity of the fundamental natural frequency of an MRE sandwich plate (plate A) in either the absence or presence of a localised external magnetic field at 3 different geometrical locations, for both small and medium magnetic fields. Furthermore, experiments have also been conducted on a pure aluminium plate (plate B) with an equal thickness to the MRE sandwich plate (plate A) in order to examine the influence of the MRE layer on the nonlinear dynamics of the system. An electrodynamic shaker was used to directly force each system and the displacement at the centre of the plate was measured. Meanwhile, permanent magnets were used to apply a localised magnetic field for the experiments where the MRE sandwich plate was subject to an external magnetic field. It was observed all the MRE systems displayed strong hardening-type nonlinear behaviour, however, with increasing magnetic field this behaviour transitioned to a weak hardening-type nonlinearity.

• Steel and Composite Structures
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• v.13 no.4
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• pp.327-341
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• 2012

With the advantages of large span, light deadweight and convenient construction, the steel-concrete composite beam (SCCB) has been rapidly developed as a medium span bridge. Compared with common beams, the global stiffness of SCCB is discontinuous and in a staged distribution. In this paper, the analysis model for the simply-supported SCCB is established and the vibration equations are derived. The natural vibration characteristics of a simply-supported SCCB are analyzed, and are compared with the theoretical and experimental results. A curvature mode measurement method is proposed to identify the shear connector damage of SCCB, with the stiffness reduction factor to describe the variation of shear connection stiffness. By analysis on the $1^{st}$ to $3^{rd}$ vertical modes, the distribution of shear connectors between the steel girder and the concrete slab are well identified, and the damage locations and failure degrees are detected. The results show that the curvature modes can be used for identification of the damage location.

• Journal of the Korean association of regional geographers
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• v.17 no.3
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• pp.259-269
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• 2011

The meaning of fengshui was another cultural ecological environment in the pre-modern in Korea. Village residents made interrelations with village natural environment by the medium of the geomantic landscape. The functions of cultural ecology through the village fengshui are as follows: the spatial location, the population inflow, the regulation of the community's production or construction or land-use, the adjustment of the environmental carrying capacity, the environmental management, the forming of the collective environmental perception and attitude. Village fengshui is a cultural adaptation strategy to the local environment for the village residents. Fengshui can be evaluated as a traditional cultural ecological way and knowledge system for keeping sustainable village environment in East Asia.

• Journal of Microbiology and Biotechnology
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• v.7 no.3
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• pp.180-188
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• 1997

Bacillus subtilis C9 was selected by measuring the oil film-collapsing activity and produced biosurfactant in a medium containing glucose as a sole carbon source. The biosurfactant emulsified hydrocarbons, vegetable oils and crude oil, and lowered the surface tension of culture broth to 28 dyne/cm. A biosurfactant, C9-BS produced by B. subtilis C9 was purified by ultrafiltration, extraction with chloroform and methanol, adsorption chromatography, and preparative reversed phase HPLC. Structural analyses, IR spectroscopy, FAB mass spectroscopy, amino acid composition, and NMR analyses, demonstrated that C9-BS was a lipopeptide comprising a fatty acid tail and peptide moiety. The lipophilic part consisting of $C_{14}\;or\;C_{15}$ hydroxy fatty acid was linked to the hydrophilic peptide part, which contained seven amino acids (Glu-Leu-Leu-Val-Asp-Leu-Leu) with a lactone linkage.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.375-380
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• 2015

Recently, methane has attracted much attention as an alternative carbon feedstock since it is the major component of abundant shale and natural gas. In this work, we produced methanol from methane using whole cells of Methylosinus trichosporium OB3b as the biocatalyst. M. trichosporium OB3b was cultured on NMS medium with a supply of 7:3 air/methane ratio at 30℃. The optimal concentrations of various methanol dehydrogenase inhibitors such as potassium phosphate and EDTA were determined to be 100 and 0.5 mM, respectively, for an efficient production of methanol. Sodium formate (40 mM) as a reducing power source was added to enhance the conversion efficiency. A productivity of 49.0 mg/l·h, titer of 0.393 g methanol/l, and conversion of 73.8% (mol methanol/mol methane) were obtained under the optimized batch condition.

• Journal of the Korean Magnetic Resonance Society
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• v.3 no.1
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• pp.44-51
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• 1999

An enzyme derived conformational changes of cobalamine is thought to be important in the homolytic cleavage of Co-C bond which is the first step of catalytic Cl-cycle of coenzyme B12-dependent enzymes. Modern 2D-NMR and NMR-based distance geometric studies were carried out to determine the 3D structure of corrin ring. Homonuclear and heteronuclear correlation NMR experiments were performed for complete 1H-NMR signal assignments. Distances between numerous proton pairs were deduced based on the NOE cross peak intensities and subsequently used as input into the distance geometry program for the 3D structure determination. The detailed 3D structure from the present NMR-based analysis was compared with the result from X-ray crystallographic study, which revealed greater conformational changes occur in benzimidazole group and sugar ring than in macrocyclic corrin and tetrapyrrole. In addition, the distance geometry used in this study was found to be quite useful for NMR-based structure determination of medium-sized molecules that give poor NOE effects arising from their intermediate tumbling rate ($\omega$$\tau$c 1.0).

• YAKHAK HOEJI
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• v.53 no.1
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• pp.12-18
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• 2009

The aim of this study was to develop antitoxic compound for cadmium-induced cytotoxic Vero cells. These cells were divided into five groups; control group (medium only), cadmium group (cadmium only), and two experimental groups. SRB (sulphorodamine B) assay was performed to evaluate the cytotoxicity of cell organelles. After cadmium was treated on Vero cells, we determined IC50 values to examine the detoxification effects of Houttuynia cordata methanol extract and quercetin under cadmium-induced cytotoxicity. Furthermore, morphological changes were observed by the light microscope. In Vero cells, methanol extract of Houttuynia cordata, and quercetin showed inhibitory effects on cadmium-induced cytotoxicity and these detoxification effects were increased in a concentration-dependent manner. These results suggest that methanol extract and quercetin from Houttuynia cordata retain a potential antitoxic activity.