• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.1285-1286
• /
• 2010

• Korean Journal of Veterinary Service
• /
• v.44 no.4
• /
• pp.247-256
• /
• 2021

The recombinant lysozyme-HJL34 proteins were expressed and purified using commercial Escherichia (E.) coli expression system. Stx2e⁺ F18⁺ E. coli, Actinobacillus pleuropneumoniae (APP), Streptococcus (S.) suis, and Clostridium (C.) perfringens strains were isolated from pigs. The minimum inhibitory concentrations (MICs) of the recombinant lysozyme-HJP34 proteins were examined by means of the microtiter plate method, according to the NCCLS recommendations. The possibility of its as the alternatives to antibiotics was tested in piglets. The MICs were determined as 75 ㎍/mL, 300 ㎍/mL, 75 ㎍/mL, 35.5 ㎍/m against Stx2e⁺ F18⁺ E. coli, APP, S. suis, C. perfringens, respectively. A total of 25 piglets were divied 5 groups. The piglets in group A~C were fed with commercial feed and those in groups D, E were fed with commercial feedstuff. All piglets in groups B~E were challenged with virulent Stx2e⁺ F18⁺ E. coli, APP, S. suis strains. Groups C and D were treated with antimicrobial from 24 h after challenge. All piglets in group B died within 3 days after challenge. Among 5 piglets in groups C and D piglets, 80% survived after challenge. Among group E piglets, 60% were alive until the end of this study. Therefore, this study indicates that recombinant lysozyme-HJP34 proteins is a suitable possibility as a feed additive for reduction of diseases by bacterial pathogens in piglet feed.

• Membrane Journal
• /
• v.11 no.4
• /
• pp.143-151
• /
• 2001

We have fabricated mixed-ionic conducting membranes, L $a_{0.6}$S $r_{0.4}$ $Co_{0.2}$F $e_{0.8}$ $O_{3-}$$\delta$/ and L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ by the solid state method. Ceramic membranes consisted of perovskite-type structures and exhibited high relative density, >95%. Especially, dense L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ layer was coated on the L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes by using screen printing technique in order to improve oxygen ion flux. We measured oxygen ion flux on uncoated L $a_{0.6}$S $r_{0.4}$ $Co_{0.2}$F $e_{0.8}$ $O_{3-}$$\delta$/, uncoated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/, and coated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes. The L $a_{0.6}$S $r_{0.4}$ $Co_{0.2}$F $e_{0.8}$ $O_{3-}$$\delta$/ membranes showed the highest flux, 0.26 mL/min.$\textrm{cm}^2$ at 90$0^{\circ}C$, after steady state had been reached. The oxygen flux of coated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes showed higher value, 0.19 mL/min.$\textrm{cm}^2$ at 95$0^{\circ}C$. This flux was as much as 2 or 3 times higher than those of uncoated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes. 3-$\delta$/ membranes.X> 3-$\delta$/ membranes.membranes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.265-268
• /
• 1999

In this study, we investigated the electromagnetic Properties of M $n_{Y}$Z $n_{1-x}$ F $e_{x}$ $O_4$(X=0.67~0.69, Y=0.13~0.19) doped with and without H $o_2$ $O_3$(each of 0.05~ 0.2wt%, step 0.05wt%). The greatest initial permeability of composition is M $n_{0.17}$Z $n_{0.16}$F $e_{0.67}$ $O_4$. As X and Y components, increased. generally resistivity slightly change by the various X and Y components. The initial permeability of M $n_{0.17}$Z $n_{0.16}$F $e_{0.67}$ $O_4$ doped with H $o_2$ $O_3$ showed the about 2.5 times higher than that of M $n_{0.17}$Z $n_{0.16}$F $e_{0.67}$ $O_4$ doped without H $o_2$ $O_3$EX>EX>EX>X>>EX>EX>EX>X>

• Journal of the korean Society of Automotive Engineers
• /
• v.4 no.1
• /
• pp.31-39
• /
• 1982

In this paper, the stress intensity factors at the crack tips in a finite plate having a straight crack with arbitrary lengths and directions are analyzed by means of Boundary Collocation Method in Cartesian coordinates under the following two cases. A) Case of only considering stress components at the boundary collocation points B) Case of considering stress resultant at the boundary, in addition to case of )A) and analyzed by means of F.E.M. To certify the Boundary Collocation Method the solutions of B.C.M. are compared with the solutions of F.E.M. demonstrates the simplicity of input data preparation and the reduction of cpu time against F.E.M.

• Journal of the Korean Mathematical Society
• /
• v.41 no.1
• /
• pp.39-50
• /
• 2004

In [25] Taskinen shows that if $\{E_n\}_n\;and\;\{F_n\}_n$ are two sequences of Frechet spaces such that ($E_m,\;F_n$) has the BB-property for all m and n then (${\Pi}_m\;E_m,\;{\Pi}_n\;F_n$) also has the ΒΒ-property. Here we investigate when this result extends to (i) arbitrary products of Frechet spaces, (ii) countable products of DFN spaces, (iii) countable direct sums of Frechet nuclear spaces. We also look at topologies properties of ($H(U),\;\tau$) for U balanced open in a product of Frechet spaces and $\tau\;=\;{\tau}_o,\;{\tau}_{\omega}\;or\;{\tau}_{\delta}$.

• Journal of Welding and Joining
• /
• v.7 no.3
• /
• pp.19-27
• /
• 1989

Both the SS41 steel and the M.E.F(martensite encapsulated islands of frrite) dual phase steel made of SS41 steel by heat treatment were welded by friction welding, and then manufactured machinemade Vnotch standard Charpy impact specimens and precracked with a fatigue system at BM(base metal), HAZ(heat affected zone) and WZ(weld interface Zone). The impact test of them was performed with an instrumented impact test machine at a number of temperatures in constant loading velocity and the dynamic fracture characteristics were studied on bases of the absorbed energy, dynamic fracture toughness and fractography from the test. The results obtained are as follows; At the room temperature, the absorbed energy is HAZ.geq.WZ.geq.BM in case of the M.E.F. dual phase steel: BM.geq.HAZ.geq.WZ in case of the SS41 steel, HAZ.geq.BM.geq.WZ at the low temperature. The absorbed energy is decreased markedly with the temperature lowering; it is highly dependent on the temperature. The dynamic fracture toughness of the M.E.F. dual phase steel is HAZ.geq.WZ.geq.BM at the room temperature; BM.geq.WZ.geq.HAZ below-60.deg. C. Therefore the reliability of friction welding is uncertain at the low temperature(below-60.deg. C). The dynamic fracture toughness of the SS41 steel; HZA.geq.WZ.geq.BM at overall temperature region. The flaw formed by rotational upsetting pressure was shown y SEM; in this region. The absorbed energy per unit area and dynamic fracture toughness were low relative to other region.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.6
• /
• pp.789-796
• /
• 2000

In order to analyze the effects of tktA, $aroF^{FBR}$, and aroL expression in a tryptophan-producing Escherichia coli, a series of plasmids carrying the genes were constructed. Introduction of tktA, $aroF^{FBR}$, and aroL into the E. coli strain resulted in approximately 10-20 fold increase in the activities of transketolase, the feedback inhibition-resistant 3-deoxy-D-arabinoheptulsonate-7-phosphate synthase, and shikimate kinase. Expression of $aroF^{FBR}$ in the aroB mutant strain of E. coli resulted in the accumulation of 10 mM of 3-deoxy-D-arabinoheptulsonate-7-phosphate (DAHP) in the medium. Simultaneous expression of tktA and $aroF^{FBR}$ in the strain further increased the amount of excreted DAHP to 20 mM. In contrast, the mutant strain which has no gene introduced accumulated 0.5 mM of DAHP. However, the expression of tktA and $aroF^{FBR}$ in a tryptophan-producing E. coli strain did not lead to the increased production of tryptophan, but instead, a significant amount of shikimate, which is an intermediate in the tryptophan biosynthetic pathway, was excreted to the growth medium. Despite the fact that additional expression of shikimate kinase in the strain could possibly remove 90% of excreted shikimate to 0.1 mM, the amount of tryptophan produced was still unchanged. Removing shikimate using a cloned aroL gene caused the excretion of glutamate, which suggests disturbed central carbon metabolism. However, when cultivated in a complex medium, the strain expressing tktA, $aroF^{FBR}$, and aroL produced more tryptophan than the parental strain. These data indicate that additional rate-limiting steps are present in the tryptophan biosynthetic pathway, and the carbon flow to the terminal pathway is strictly regulated. Expressing tktA in E. coli cells appeared to impose a great metabolic burden to the cells as evidenced by retarded cell growth in the defined medium. Recombinant E. coli strains harboring plasmids which carry the tktA gene showed a tendency to segregate their plasmids almost completely within 24h.

• Microbiology and Biotechnology Letters
• /
• v.26 no.1
• /
• pp.15-22
• /
• 1998

The dnrF gene, responsible for conversion of aklavinone to $\varepsilon$-rhodomycinone via C-11 hydroxylation, was mapped in the daunorubicin gene cluster of Streptomyces peucetius subsp. caesius ATCC 27952, close to drrAB, one of the anthracycline resistance genes. To characterize the enzymatic properties of the aklavinone 11-hydroxylase, the dnrF gene was overexpressed in Escherchia coli. The pET-22(+) plasmid which has the T7 promoter under the control of lacUV5 gene was used for the overexpression of the dnrF gene, and the recombinant plasmid pET213 that contains the dnrF gene linked to the T7 promoter of pET-22b(+) was introduced into the E. coli BL2l. When the expression of the dnrF gene was induced by IPTG at the final concentration of 1 mM, the induced protein could be detected in SDS-PAGE only in insoluble precipitate. The insoluble protein was electroeluted from the gel and used for the preparation of antiserum in mice. Various culture conditions were tested to maximize the expression of the aklavinone 11-hydroxylase in soluble form. The enzymatic activity was checked by the bioconversion experiment, and the protein was confirmed by the SDS-PAGE and the Western blot analysis. From the analysis of the data, it was concluded that the culture induced with IPTG at the final concentration of 0.02 mM at 37$^{\circ}C$ yielded the best productivity of active form of enzyme.

• The Korean Journal of Ceramics
• /
• v.4 no.3
• /
• pp.204-206
• /
• 1998

The Gibbs free energy of formation of $BaThO_3$ from elemental oxides has been measured at temperatures between 853 and 903 K using a $CaF_2$ solid electrolyte galvanic cell. The galvanic cell consisted of Pt, $O_2, CaO+CaF_2 \parallel CaF_2 \parallelBaThO_3+ThO_2+BaF_2, O_2$, Pt EMF gave the standard Gibbs free energy for the reaction $CaF_2+BaThO_3=CaO+BaF_2+ThO_3$ as $\DeltaG^o$,/TEX>=124111.031-117.597 T(J/mol).