• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.2
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• pp.235-251
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• 1997

A numerical simulation on the combined natural convection and radiation is carried out in a partially open rectangular enclosure with a heater by using the finite volume and the S-8 discrete ordinate methods. The fluid inside the enclosure is considered as an absorbing, emitting and anisotropic scattering media. The heater causes a natural circulation of the fluid (10$^{5}$ $^{9}$ ) which results in significant in-flow of the ambient cold fluid through the partially open wall. Comparing the results of pure convection with those of the combined convection- radiation, the combined heat transfer results with small Planck numbers (P$_{l}$ <1.0) show much stronger circulation than those of the pure convection, and the fluid circulation is more evident for larger Rayleigh numbers. When one of three radiative properties - the medium absorption coefficient, the wall reflectivity, and the scattering albedo - increases, the fluid circulation and the heat transfer in the enclosure are reduced. The location of the heater and the open ratio of the right wall are also shown to affect the fluid circulation and heat transfer significantly. However, the anisotropy of the scattering phase function is shown to be unimportant for the fluid circulation and heat transfer within the enclosure considered in this study.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1197-1206
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• 2005

Vibrio vulnificus is an opportunistic pathogen that causes a septicemia and expresses numerous virulence factors, in which luxS and smcR are genes encoding for components responsible for quorum-sensing regulation. In the present study, null mutants were constructed with lesions in each or both of these two genes from the V. vulnificus Vv$\Delta$Z strain, which is a lacZ$^{-}$ and chloramphenicol/streptomycin-resistant derivative of the wild-type ATCC29307 strain, and their phenotypes related to virulence were compared with those of the parental cells. $LD_{50}$ and histopathological findings of luxS-, smcR-, or luxS- smcR- deficient mutant were not different from those of the parent strain, a lacZ-deficient streptomycin-resistant strain in mice. However, time of death in mice was delayed, and numbers of bacteria survived in bloodstream after intraperitoneal injection in mice were decreased by mutation, especially luxS and smcR double mutant (VvSR$\Delta$ZSR). These phenomena were supported by increased serum sensitivity and delayed bacterial proliferation in both murine blood and iron-restricted medium. These results suggest that the luxS and luxR homologous genes in V. vulnificus could playa role in bacterial survival in host by enhancing proliferation and adjusting to changed environment.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.94-100
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• 2006

To isolate a bacterium that produces plant growth promoting hormone, a total of 29 bacteria were obtained from the soil in Gyeongsan, Korea. Among these, 14 strains were selected by their positive reaction on Salkowski to produce auxin. All of these were then tested for their property to produce siderophore using CAS (chrome azurol S) blue agar, and one was chosen for its ability to produce both, auxin and siderophore. This strain, denoted, AHl8, showed 1.5 times higher adventitious root induction rates than controls, using mung-beans. The strain also showed efficient biocontrol properties towards Fusarium-wilt of tomatoes in artificial pot assays. The strain was identified as Bacillus subtilis by 16s rDNA comparison and Biolog analyses. Growth and media conditions for Bacillus subtilis AH1 8 to highly produce siderophore were also investigated.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2643-2647
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• 2011

Efficient ditopic receptor, uranyl(II) N,N'-(ethylenedioxy)benzenebis(salicylideneimine) (3) for beryllium ion has been obtained upon functionalization of 1,2-ethylenedioxybenzene (1) with a uranyl-salphen (salphen = N,N'-phenylenebis(salicylideneimine)) unit. Binding affinities of the receptor, 3 in AN-DMSO (v/v 95:5) solution have been measured for alkali and alkaline earth metal ions by conductometry comparing 1. The results showed that both monotopic 1 and ditopic receptor 3 were selective for $Be^{2+}$ ions over other cations, while especially 3 that can complex both with cations (coordinated to basic oxygen of ethylenedioxybenzene) and anions (coordinated to the Lewis acidic uranyl center) results in an increase of the stability constants by a factor of $10^{2.42}$ with respect to 1. Furthermore, the $Be^{2+}$-3 interactions are demonstrated by $^1H$ NMR experiments in highly polar solvent medium, DMSO-$d_6$. Higher selectivities were also observed for $Be^{2+}$ when the ditopic receptor, 3 was incorporated into PVC membranes and tested as ion selective electrodes at neutral pH.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.49-60
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• 2003

Several growth factors and polypeptides are not commonly yet used for regenerators of bone tissue or alveolar bone because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many herbal medicines, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, antiinflammatory and regenerative potential of periodontal tissues. Morindae Radix, Cibotium Barometz (L.), Albizziae Cortex, Cistandhis Herba have been traditionally used as medicines for treatment of bone disease in Eastern medicine. The objective of the present study is to examine the ability of alkaline phosphatase (ALP) activity of human fetal osteoblast (hFOB1) when several natural medicines were supplemented. hFOB1 were cultured with Dulbecuo's Modified Eagle's Medium Nutrient Mixture F-12 HAM ( DMEM/F-12 1:1 Mixture, Sigma, USA) and negative control, dexamethasone (positive control), and each natural medicines for 3 days. And then ALP activity was measured by spectrophotometer for enzyme activity and Alizarin red S staining for morphometry. Among the natural medicines of this study, Morindae Radix, Cibotium Barometz (L.) and Cistanchis Herba induced higher activity of ALP synthesis than negative controls in all experimental group. Albizziae Cortex showed mild increases than negative control group. According to measurement of positively stained area, all of the natural medicines of this study increased compared to negative control. Especially, Cibotium Barometz (L.) and Cistanchis Herba showed statistical significance compared to negative control (p<0.05). These results indicate that Morindae Radix, Cibotium Barometz (L.), Albizziae Cortex, Cistandhis Herba have an inducing ability of ALP synthesis on osteoblast.

• Animal cells and systems
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• v.3 no.4
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• pp.385-391
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• 1999

Changes in the levels of prostaglandian F$_{2a}$ (PGF$_{2a}$) and E$_2$ (PGE$_2$) in culture medium during in vitro ovulation of Rana dybowskii follicles were examined. The ovulation was induced by frog pituitary homogenate (FPH) or TPA (12-O-tetradecanoylphorbol-13-acetate, a protein kinase activator) and the levels of PGs were measured by radioimmunoassay. When the ovarian follicles were cultured, only a few oocytes were ovulated by 12 h, but half of them were ovulated by 24 h in response to FPH, whereas around 30% of oocytes were ovulated by 12 h and maximum ovulation (around 50%) occurred by 24 h in response to TPA. Without any stimulation (control), no ovulation occurred. TPA elevated the level of PGF$_{2a}$ to high levels when compared to control (basal levels), but the increase by FPH was less evident. Likewise, the levels of PGE$_2$ increased markedly in response to TPA, but rather decreased by FPH treatment. Interestingly, PGF$_{2a}$ induced ovulation but PGE$_2$ suppressed FPH- or PGF$_{2a}$-induced oocyte ovulation. Basal levels of PGs Increased steadily during culture. When theca/epithelium (THEP) layer and granulosa cell-enclosed oocytes (GCEOs) were separated by microdissection and cultured independently, higher levels of both PGs were secreted by THEP than by GCEOS. Synthesis of PGs by follicle or follicular components was strongly suppressed by exogenous cAMP or indomethacin. These results suggest that: 1) PGF$_{2a}$ plays an important role in Rana ovulation, 2) protein kinase C is involved in PGs production, and 3) thecal epithelium layer is responsible for the PGs production in Rana.

• Journal of Sericultural and Entomological Science
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• v.41 no.2
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• pp.102-107
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• 1999

To analysis a promoter strength of Atographa californica nucler polyhedrosis virus (AcNPV) IE1 gene, an immediate viral gene, ${\beta}$-glactosidase gene as a reporter gene was introduced under the control of the IE1 promoter. The restriction fragment containing IE1 promoter and ${\beta}$-galctosidase gene from pAcIE1-gal were inserter into pBacPAK9 to yield transfer vector pAcNPV-IE1-gal. The pAcNPV-IE1-gal was cotransfected with AcNPV genomic DNA BacPAK6 into Sf9 cells to produce recombinant baculovirus AcNPV-IE1-gal. In addition, recombinant bacvulovirus AcNPV-gal, which express ${\beta}$-galac-tosidase under the control of the polyhedrin promoter, was constrer, was constructed to compared with AcNPV-IE1-gal. The recombinant viruses were respectively infected into Sf9 cells and characterized by the virus titer and expression of ${\beta}$-galactoxidase in Sf9 cells. The promoter strength of IE1 and polyhedrin promoters was determined by the amount of ${\beta}$-galactosidase secreted into medium by viral infection. The titer of AcNPV-IE1-Gal determined by plaque assays in Sf9 cells was similar to that of AcNPV-gal. However, expression level of ${\beta}$-galactosidase by AcNPV-IE1-gal was significantly lower than that by AcNPV-gal. In conclusion, promoter strength of IE1 was approximately 25-fold lower than that of polyhedrin.

• Korean Institute of Interior Design Journal
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• v.20 no.4
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• pp.54-62
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• 2011

Fast industrialization caused from Descartes' dichotomy has enormously developed our world, but endangered the ecosystem. In this study, the ecosystem aesthetics is not only a critique against existing growth-ideology and technical civilization, but also the art pursuing the life as an artistic state and achieving the dream for qualitatively different new future. Lao-tzu's Natural Beauty assumes that the adaptation to natural laws can lead every purpose's achievement. Based on such theoretical alternative, the earth construction as a medium for coexisting mankind, nature and construction interacts with the other objects through the natural affinity, the energy efficiency, the material generation. The earth construction provides the images of naivety, naturalness, folk as well as emotional stability in cultural terms. This study's direction and method are as follows. First, it researches the ecosystem aesthetics from the Taoism viewpoint, the alternative for environmental healing based on theoretical reviews about the ecosystem aesthetics. Second, it researches the earth construction's ecosystem aesthetic features and construction features from the low-tech aspect in continual construction genealogy. Third, it analyzes some cases targeting domestic buildings by drawing out expression methods and features through the connectivity of earth construction and ecosystem aesthetics. The earth construction lies between the heaven and the earth, but coexists in natural cycle. The earth construction caused from ecosystem aesthetics will be a future alterative, and various studies about its features and methods should be continued.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.50-58
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• 1996

Interspecific hybrids between Aspergillus oryzae var oryzae and A. nidulans 514 were obtained by nuclear transfer technique. Several autotrophic mutants isolated from conidiospores of the two strains were mutagenized with ultraviolet and N-methyl-N-nitrosoguanidine. Optimal conditions for formation of intergeneric hybrids were investigated. Frequencies of hybrid formation by nuclear transfer were $3{\times}10^{-5}{\sim}1{\times}10^{-5}$. From observation of genetic stability, conidial size, DNA content, and nuclear stain, it was suggested that their karyptypes are aneuploid. The hybrids showed 1.1~1.4 fold higher xylanase activities than parental strains did. The xylanase of Aspergiilus sp. TAVD514-3 was purified and some of it's enzymatc characteristics were investigated. The enzyme was purified about 85 fold with an overall yield of 17% from the culture medium by ammonium sulfate fractionation, Sephadex G-75 gel permeation chromatography, and CM-sephadex A-50 ion exchange chromatography. The purified enzyme functions optimally at pH 9.0 and 80$^{\circ}C$. The enzymatic activity was increased by the presence of $Mg^{2+}$ and $Mn^2$ ions.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.250-256
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• 2006

The optimum cultural conditions for production of Monascus natural pigment by Monascus purpureus MK2 were investigated in submerged culture. This strain was showed the maximum production of monascus natural pigment in the optimal medium of 3.0% wheat flour, 0.15% $NaNO_3$, 0.2% $K_{2}HPO_4$ and 0.05% $MgSO_4{\cdot}7H_{2}O$, at pH 7.0. The maximum production of this pigment was achieved at $30^{\circ}C$ for 7 day cultivation under 130 rpm shaking. At optimal condition, Monascus purpureus MK2 produced 29.10, 36.84 and 48.92 units of yellow, orange and red pigment, respectively.