• Research in Plant Disease
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• v.17 no.2
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• pp.111-120
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• 2011

A bacterial artificial chromosome library of Pectobacterium carotovorum 35 was constructed to characterize the genome and to sequence its hrp region. The hrp cluster of P. carotovorum 35 consisted of 26 open reading frames in five operons. A promoter-based green fluorescent protein technology was used to identify the genes regulated by the alternative sigma factor, HrpL, in P. carotovorum 35. The majority of the selected clones contained the hrpJ operon promoter sequence, which harbors a hrp box, but no putative hrp boxes were detected within the promoter sequences of two other hrpL-regulated genes encoding for pectate lyase and large repetitive protein. Although the promoters of five other hrp operons also contained hrp boxes, their expression was not HrpL-dependent in the promoter-based selection in E. coli. However, transcriptional analysis showed that expression from all operons harboring hrp boxes, except for the hrpN operon, was reduced significantly in the hrpL mutant. The severity of soft-rot symptoms when the hrpL mutant was applied to the surface of tobacco leaves, mimicking natural infection, was greatly attenuated. These results indicate that the hrpL gene of P. carotovorum 35 may be involved in the development of soft-rot symptoms.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.68-72
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• 2002

While the biosynthetic gene cluster encoding the pigmented antibiotic actinorhodin is present in the two closely related bacterial species, Streptomyces lividans and Streptomyces coelicolor, it normally is expressed only in S. coelicolor---generating the deep blue colonies responsible for the S. coelicolor name. However, multiple copies of the afsR2 gene, which activates actinorhodin synthesis, result in the ability of S. lividansto also synthesize large amounts of actinorhodin. Here we report that the phenotypic property that historicially distinguishes these two Streptomycesspecies is determined conditionally by the carbon source used for culture. Whereas growth on glucose repressed actinorhodin production in S. lividans, culture on solid media containing glycerol as the sole carbon source dramatically increased the expression of afsR2 mRNA---leading to extensive actinorhodin synthesis by S. lividansand obliterating its phenotypic distinction from S. coelicolor. afsR2 transcription under these conditions was developmentally regulated, rising sharply at the time of aerial mycelium formation and coinciding temporally with the onset of actinorhodin production. Our results, which identify media-dependent parallel pathways that regulate actinorhodin synthesis in S. lividans, demonstrate carbon source control of actinorhodin production through the regulation of afsR2 mRNA synthesis. The nucleotide sequences of afsR2 revealed two putative important domains; the domain containing direct repeats in the middle and the domain homologous to sigma factor sequence in the C-terminal end. In this work, we constructed various sized afsR2-derivatives and compared the actinorhodin stimulating effects in S. lividans TK21. The experimental data indicate that the domain homologous to sigma factor sequence in the C-terminal end of afsR2 plays a critical role as an antibiotic stimulating function. In addition, we also observed that the single copy integration of afsR2 regulatory gene into S. lividans TK21 chromosome significantly activates antibiotic overproduction.

• Journal of the Korean Geotechnical Society
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• v.30 no.8
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• pp.25-37
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• 2014

In load and resistance factor design (LRFD) method, resistance factors are typically calibrated using resistance bias factors obtained from either only the data within ${\pm}2{\sigma}$ or the data except the tail values of an assumed probability distribution to increase the reliability of the database. However, the data selection approach has a shortcoming that any low-quality data inadvertently included in the database may not be removed. In this study, a data quality evaluation method, developed based on the quality of static load test results, the engineering characteristics of in-situ soil, and the dimension of aggregate piers, is proposed for use in constructing database. For the evaluation of the method, a total 65 static load test results collected from various literatures, including static load test reports, were analyzed. Depending on the quality of the database, the comparison between bias factors, coefficients of variation, and resistance factors showed that uncertainty in estimating bias factors can be reduced by using the proposed data quality evaluation method when constructing database.

• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.193-198
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• 2016

Early-type galaxies (ETGs) are supposed to follow the virial relation $M=k_e{\sigma}^2R_e/G$, with M being the mass, σ_* being the stellar velocity dispersion, R_e being the effective radius, G being Newton's constant, and k_e being the virial factor, a geometry factor of order unity. Applying this relation to (a) the ATLAS^3D sample of Cappellari et al. (2013) and (b) the sample of Saglia et al. (2016) gives ensemble-averaged factors 〈k_e〉 = 5.15 ± 0.09 and 〈k_e〉 = 4.01 ± 0.18, respectively, with the difference arising from different definitions of effective velocity dispersions. The two datasets reveal a statistically significant tilt of the empirical relation relative to the theoretical virial relation such that $M{\propto}({\sigma}^2_*R_e)^{0.92}$. This tilt disappears when replacing R_e with the semi-major axis of the projected half-light ellipse, a. All best-fit scaling relations show zero intrinsic scatter, implying that the mass plane of ETGs is fully determined by the virial relation. Whenever a comparison is possible, my results are consistent with, and confirm, the results by Cappellari et al. (2013). The difference between the relations using either a or R_e arises from a known lack of highly elliptical high-mass galaxies; this leads to a scaling (1 - ϵ ) ∝ M^0.12, with ϵ being the ellipticity and $R_e=a\sqrt[]{1-{\epsilon}}$. Accordingly, a, not R_e, is the correct proxy for the scale radius of ETGs. By geometry, this implies that early-type galaxies are axisymmetric and oblate in general, in agreement with published results from modeling based on kinematics and light distributions.

• Journal of the Korean Electrochemical Society
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• v.20 no.3
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• pp.55-59
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• 2017

In this study, thermoelectric characteristics of perovskite $La_{0.5}Ca_{0.5}MnO_3$ (LCMO) nanomaterials were investigated by theoretical simulation and experimental analysis. Thermoelectric power factors calculated by DFT simulation were gradually enhanced as increase in annealing temperature. Maximum power factor was obtained with high magnitude of $S^2{\sigma}=566{\mu}W/m{\cdot}K^2$ at 1100 K through a dominant improvement of Seebeck coefficient compared with electrical conductivity. Experimentally, the LCMO nanomaterials were hydrothermally synthesized and then treated by post thermal annealing with temperature variation. X-ray diffraction and SEM analysis illustrated that LCMO exhibited orthorhombic perovskite structures with small grain size of 16~19 nm over 873 K. The results directly confirmed that improvement of crystallinity and decrease of mean grain size given by post thermal annealing lead to enhancements of electrical conductivity and Seebeck coefficient, respectively.

• Bulletin of the Korean Chemical Society
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• v.15 no.10
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• pp.891-896
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• 1994

Reactions of mer, trans-$Re({\equiv}NC_6H_5)(PPh_3)_2Cl_3$, I, with $PMe_3$ and $P(OMe)_34 at room temperature, led to mer, trans-$Re({\equiv}NC_6H_5)(PPh_3)(PMe_3)Cl_3$, II, and fac-$Re({\equiv}NC_6H_5)(PPh_3)(P(OMe)_3)Cl_34, III, respectively. The crystal structures of II and III were determined through X-ray diffraction. Ⅱ crystallizes in the orthorhombic system, space group $Pna2_1$ with cell parameters a=19.379(4) ${\AA}$, b=11.867(2) ${\AA}$, c = 12.676(3) ${\AA}$, and Z = 4. Least-squares refinement of the structure led to a $R(wR_2)$ factor of 0.0251 (0.0621) for 2203 unique reflections of $I>2{\sigma}(I)$ and for 306 variables. III crystallizes in the monoclinic system, space group $P2_1/n$ with cell parameters a=11.399(3) ${\AA}$, b=14.718(4) ${\AA}$, c=17.558(5) ${\AA}$, ${\beta}=97.79(2){\circ}$, and Z=4. Least-squares refinement of the structure led to a $R(wR_2)$ factor of 0.0571 (0.1384) for 3739 unique reflections of $I>2{\sigma}(I)$ and for 344 variables. Structural studies showed that the relative orientations of the two phosphines in both complexes are different, probably due to the differences in the coordinating abilities between $PMe_3$ and $P(OMe)_3$ to the 5-coordinate fluxional intermediate.

• Geomechanics and Engineering
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• v.11 no.6
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• pp.739-756
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• 2016

The shear strength reduction finite element method (SSRFEM) is a powerful tool for slope stability analysis. The factor of safety (FOS) of the slope can be easily calculated only through reducing effective cohesion (c′) and tangent of effective friction angle ($tan{\varphi}^{\prime}$) in equal proportion. However, this method may not be applicable to soil slope under wetting-drying cycles (WDCs), because the influence of WDCs on c′ and $tan{\varphi}^{\prime}$ may be different. To research the method of estimating FOS of soil slopes under WDCs, this paper presents an experimental study firstly to investigate the effects of WDCs on the parameters of shear strength and stiffness. Twelve silty clay samples were subjected to different number of WDCs and then tested with triaxial test equipment. The test results show that WDCs have a degradation effect on shear strength (${\sigma}_1-{\sigma}_3)_f$, secant modulus of elasticity ($E_s$) and c′ while little influence on ${\varphi}^{\prime}$. Hence, conventional SSRFEM which reduces c′ and $tan{\varphi}^{\prime}$ in equal proportion cannot be adopted to compute the FOS of slope under conditions of WDCs. The SSRFEM should be modified. In detail, c′ is merely reduced among shear strength parameters, and elasticity modulus is reduced correspondingly. Besides, a new approach based on sudden substantial changes in the displacement of marked nodes is proposed to identify the slope failure in SSRFEM. Finally, the modified SSRFEM is applied to compute the FOS of a slope example.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1157-1163
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• 2009

Let G be a graph with vertex set V(G) and let f be a nonnegative integer-valued function defined on V(G). A spanning subgraph F of G is called a fractional f-factor if $d^h_G$(x)=f(x) for all x $\in$ for all x $\in$ V (G), where $d^h_G$ (x) = ${\Sigma}_{e{\in}E_x}$ h(e) is the fractional degree of x $\in$ V(F) with $E_x$ = {e : e = xy $\in$ E|G|}. In this paper it is proved that if ${\delta}(G){\geq}{\frac{b^2(k-1)}{a}},\;n>\frac{(a+b)(k(a+b)-2)}{a}$ and $|N_G(x_1){\cup}N_G(x_2){\cup}{\cdots}{\cup}N_G(x_k)|{\geq}\frac{bn}{a+b}$ for any independent subset ${x_1,x_2,...,x_k}$ of V(G), then G has a fractional f-factor. Where k $\geq$ 2 be a positive integer not larger than the independence number of G, a and b are integers such that 1 $\leq$ a $\leq$ f(x) $\leq$ b for every x $\in$ V(G). Furthermore, we show that the result is best possible in some sense.

• The Journal of Fisheries Business Administration
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• v.35 no.1
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• pp.117-132
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• 2004

This study attempts to suggest a new approach of the estimation of range and degree of fisheries damages caused by a large scale of reclamation undertaken in coastal area using the central limit theorem(CLT) in statistics. The key result of the study is the introduction of the new concept of critical variation of environmental factor($d_{c}$). The study defines $d_{c}$ as a standard deviation of the sample mean($\bar{X}$) of environmental factor(X), in other words, $\frac{\sigma}{ \sqrt{n}}$. The inner bound of $d_{c}$ could be the area of fisheries damages caused by public coastal undertaking. The study also defines the decreasing rate of fisheries production$\delta_{\varepsilon}$, in other words, degree of fisheries damages, as the rate of change in the distribution of sample mean(($\bar{X}$), caused by the continuous and constant variation of environmental factor. Therefore $\delta_{\varepsilon}$ can be easily calculated by the use of table of the standardized normal distribution.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.882-886
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• 2004

A nation have the regulation for a vehicle safety and interested in the side impact of a vehicle. But we spend a lot of money and time for the side impact test. So we must design a vehicle parts regard to the side impact test. This paper describes a new test method for side impact test. We used DFSS(Design For Six Sigma) process for design of door trim armrest. We searched the door trim armrest control factor and made the experiment plan. We researched the optimal design factor and improved the abdomen injury value of the human dummy.