• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1603-1608
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• 2011

Let R be a ring with identity. If a, b, $c{\in}R$ such that a+b+c = 1, then the distributive laws from addition over multiplication hold in R, that is a+(bc) = (a+b)(a+c) when ab = ba, and (ab)+c = (a+c)(b+c) when ac = ca. An application to obtains, if A,B are idempotent matrices and AB = BA = 0 then there exists an idempotent matrix C such that A + BC = (A + B)(A + C), and also A + BC = (I - C)(I - B). Some other cases and applications are also presented.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.339-346
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• 1992

These studies were carried out to identify Bacillus cereus group 1..5-] strain isolated from 5uyeong Bay. This strain was differentiated from B. cereus group using conventional, API system and fatty acid composition analysis. Colony characteristics were opague. mucoid, entire margin. convex. circular and non hemolysis on sheep blood agar plates, and were observed with central spore forming positive bacilli in a Gram stained preparation. and had no motility. The carbohydrates tested; glucose.maltose, and sucrose were assimilated but neither trehalose nor salicin were assimilated. This strain ultilized gelatin and was also inhibited by 6.5% NaCI. The results of biochemical examination were differented from B. cereus group LS-1 compared with others B. cereus group. The fatty acid composition contained major amounts of branched chain acids. iso $C_{15}$ and iso $C_{13}$ and the range of chain length was $C_{12}$ to C"$C_{17}$ and n$C_{15}$, acid was not detected. Automated fatty acid computer profile indicated "B. mycoides GC subgroup B of 0.312 similarity index." The results agreed with other research cases. On the other hand. A TB computer prolile index of API system (API 50 CHB & API 20E) identified" Doubtful profile of 99.7% B. firmus" . These results were presented with considerable discrepancies between API system and fatty acid analysis. With 67 biochemical characters. the similarity matrix of B. mycaides (KCTC 1033). B. thuringiensis (KCTC 1033). B. cereus (5-3) and B. mycoides (S-12) showed 42%. 42%. 59%, and 52%. respectively. Through the key tests and fatty acid analyses. we could notice the appearance of B. mycoides of the B. cereus group and this leads us to suspect the existence of a new biotype B. mycoides.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.605-613
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• 2022

The genus Flavobacterium, type genus of the family Flavobacteriaceae and a member of the phylum Bacteriodetes includes gram-negative and yellow-pigmented rods. Those bacteria have been isolated from various environments of the earth. A yellow-pigmented, gram-negative rod was isolated from a pond in the campus of the Changwon University, Changwon, Kyeongnam and designated as strain B1. Strain B1 was further analyzed physiologically, biochemically and phylogenetically, and concluded to be a member of genus Flavobacterium. BLAST search of the 16S rRNA gene sequence of strain B1 shows homology no higher than 99.0% with those sequences of other bacteria. The major fatty acids of strain B1 are iso-C_15:0 (19.6%), summed feature 3(C_16:1 ω7c and/or C_16:1 ω6c, 16.1%), iso-C_17:0 3OH(10.2%), iso-C_15:0 3OH(8.4%) and iso-C_15:1 G(6.6%) showing significant differences in fatty acid compositions between strain B1 and the other known Flavobacterium species. DNA sequence of 16S rRNA gene of strain B1 was deposited in genbank under accession number OP060681.

• Journal of Life Science
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• v.20 no.2
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• pp.260-268
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• 2010

The lactate dehydrogenase (EC 1.1.1.27, LDH) isozymes in tissues from Channa argus were purified and characterized by biochemical, immunochemical and kinetic methods. The activity of LDH in skeletal muscle was the highest at 380.4 units and those in heart, eye and brain tissues were 13.4, 3,5 and 5.4 units, respectively. Citrate synthase (EC 4.1.3.7, CS) activity in heart tissue was the highest at 20.7 units. LDH/CS in skeletal muscle, heart, eye and brain tissues were 172.9, 0.6, 0.32 and 0.47. Protein concentration in skeletal muscle tissue was 14.7 mg/g and specific activities of LDH in skeletal muscle, heart, eye and brain tissues were 25.88, 0.79, 0.31 and 1.38 units/mg, respectively. Therefore, skeletal muscle tissue was anaerobic and heart tissue was aerobic. The LDH isozymes in tissues were identified by polyacrylamide gel electrophoresis, immunoprecipitation and Western blot with antiserum against $A_4$, $B_4$, and eye-specific $C_4$. LDH $A_4$, $A_3B$, $A_2B_2$. $AB_3$ and $B_4$ isozymes were detected in every tissue, $C_4$, $AC_3$, $A_2C_2$ and $A_3C$ were detected in eye tissue, and $A_3C$ was found in brain tissue. LDH $A_4$, $A_3B$, $A_2B_2$, $AB_3$, $B_4$, eye-specific $C_4$ isozymes were purified by affinity chromatography and Preparative PAGE Cells. The LDH $A_4$ isozyme was purified in the fraction from elution with $NAD^+$ containing buffer of affinity chromatography. Eye-specific $C_4$ isozyme was eluted right after $A_4$, after which $B_4$ isozyme was eluted with plain buffer. As a result, one part of molecular structures in $A_4$, $B_4$ and eye-specific $C_4$ were similar, but were different from each other in $B_4$ and $C_4$. Therefore the subunit A may be conservative in evolution, and the evolution of subunit B seems to be faster than that of subunit A. The activity of LDH $A_4$, $A_2B_2$, $B_4$, and eye-specific $C_4$ isozymes remained at 39.98, 21.28, 19.67 and 16.87% as a result of the inhibition by 10 mM of pyruvate, so the degree of inhibition was very high. The $Km^{PYR}$ values were 0.17, 0.27 and 0.133 mM in $A_4$, $B_4$ and eye-specific $C_4$ isozymes, respectively. The optimum pH of LDH $A_4$, $B_4$, eye-specific $C_4$, $A_2B_2$, $A_3B$, and $AB_3$ were pH 6.5, pH 8.5, pH 5.5, pH 6.0-6.5, pH 5.0 and pH 7.5. The $A_4$ and heterotetramer isozymes stabilized a broad range of pH. Especially, LDH activities in skeletal muscle tissue were high, resulting in a high degree of muscle activity.LDH metabolism in eye tissue seems to be converted faster from pyruvate to lactate by eye-specific $C_4$ isozyme as eye-specific $C_4$ have the highest affinity for pyruvate, and right after the conversion, oxidation of lactate was induced by $A_4$ isozyme. It was found that expression of Ldh-C, affinity to substrate and reaction time of $C_4$ isozyme were different according to the ecological environmental and feeding capturing patterns.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.32-35
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• 2008

Thermally stable diffusion barrier of tungsten carbon nitride(W-C-N) and of tungsten boron carbon nitride(W-B-C-N) thin films have studied to investigate the impurity behaviors of boron and nitrogen. In this paper we newly deposited tungsten boron carbon nitride(W-B-C-N) thin film for various $W_2B$ target power on silicon substrate. The impurities of the 100nm-thick W-C-N and W-B-C-N thin films provide stuffing effect for preventing the inter-diffusion between W-C-N or W-B-C-N thin films and silicon during the high temperature($700^{\circ}C{\sim}1000^{\circ}C$) annealing process.

• Journal of dental hygiene science
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• v.22 no.3
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• pp.156-163
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• 2022

Background: This study attempted to apply resin infiltrant (RI) as a method to maintain the effect of tooth bleaching treatment and compared it with fluoride varnish (FV) or artificial saliva to evaluate the effect. Methods: Sixty healthy lozenge specimens were classified into five groups. Group 1 was the negative control group, and discoloration was induced after artificial saliva treatment of the tooth specimen (G1_S+C). Group 2 was a positive control group, in which pigmentation was induced after bleaching treatment and artificial saliva treatment (G2 _B+S+C). Coloration was induced in group 3 (experimental group 1) after bleaching treatment and artificial saliva treatment, followed by application of fluorine varnish (G3_B+FV+S+C). Coloration was induced in Group 4 (experimental group 2) after applying RI after bleaching treatment and artificial saliva treatment (G4_B+RI+S+C). Pigmentation was induced in group 5 (experimental group 3) after bleaching treatment and artificial saliva treatment, followed by acid treatment (etching) and treatment with RI (G5_B+E+RI+S+C). Coffee and wine were used to induce discoloration. The lightness value (L^*) of the CIE L^*a^*b^* color system was obtained by image analysis. Kruskal-Wallis H analysis was performed for the mean difference in L^* values by group. Results: When coloration was induced with coffee, there was no significant difference in L^* value between artificial saliva (G2 _B+S+C), FV (G3_B+FV+S+C), and RI (G4_B+RI+S+C, G5_B+E+RI+S+C) groups. There was no significant difference in L^* values between the artificial saliva (G2 _B+S+C), FV (G3_B+FV+S+C), and RI (G4_B+RI+S+C, G5_B+E+RI+S+C) groups, even in the case of wine induced coloration. Conclusion: It was confirmed that artificial saliva or RI treatment had similar effects to the FV previously used to maintain the effect of tooth bleaching treatment.

• Journal of Microbiology
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• v.44 no.6
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• pp.655-659
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• 2006

Phylogenetic studies of nef, pol, and env gene sequences of HIV-1 isolated from Koreans suggested the presence of a Korean clade in which Korean sequences are clustered to the exclusion of foreign sequences. We attempted to identify and characterize the Korean clade using all vif gene sequences isolated from Koreans registered in the NCBI GenBank database (n = 233). Most (77 %) of the Korean isolates belonged to the Korean clade as a large subcluster in subtype B, designated the Korean clade subtype B ($K_{C}B$). $K_{C}B$ sequences were relatively homogenous compared to Korean subtype B sequences that did not belong to the $K_{C}B$ (non-Korean clade subtype B; $NK_{C}B$). Comparison of amino acid frequencies of $K_{C}B$ and $NK_{C}B$ sequences revealed several positions where the amino acid frequencies were significantly different. These amino acid residues were critical in separating $K_{C}B$ from $NK_{C}B$ or from foreign sequences, since substitution of these amino acids in $K_{C}B$ with the $NK_{C}B$ amino acids relocated the $K_{C}B$ sequences to $NK_{C}B$, and vice versa. Further analyses of $K_{C}B$ will help us to understand the origin and evolutionary history of $K_{C}B$.

• Korean Journal of Mathematics
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• v.18 no.4
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• pp.335-342
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• 2010

Let D be an integral domain with quotient field K,$\mathcal{I}(D)$ be the set of nonzero ideals of D, and $w$ be the star-operation on D defined by $I_w=\{x{\in}K{\mid}xJ{\subseteq}I$ for some $J{\in}\mathcal{I}(D)$ such that J is finitely generated and $J^{-1}=D\}$. The D is called a Pr$\ddot{u}$fer $v$-multiplication domain if $(II^{-1})_w=D$ for all nonzero finitely generated ideals I of D. In this paper, we show that D is a Pr$\ddot{u}$fer $v$-multiplication domain if and only if $(A{\cap}(B+C))_w=((A{\cap}B)+(A{\cap}C))_w$ for all $A,B,C{\in}\mathcal{I}(D)$, if and only if $(A(B{\cap}C))_w=(AB{\cap}AC)_w$ for all $A,B,C{\in}\mathcal{I}(D)$, if and only if $((A+B)(A{\cap}B))_w=(AB)_w$ for all $A,B{\in}\mathcal{I}(D)$, if and only if $((A+B):C)_w=((A:C)+(B:C))_w$ for all $A,B,C{\in}\mathcal{I}(D)$ with C finitely generated, if and only if $((a:b)+(b:a))_w=D$ for all nonzero $a,b{\in}D$, if and only if $(A:(B{\cap}C))_w=((A:B)+(A:C))_w$ for all $A,B,C{\in}\mathcal{I}(D)$ with B, C finitely generated.

• Progress in Superconductivity and Cryogenics
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• v.21 no.1
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• pp.18-24
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• 2019

This study was carried out to investigate the effect of milling of boron (B), which is one of raw materials of $MgB_2$, on the critical current density ($J_c$) of $MgB_2$. B powder used in this study is semi-amorphous B (Pavezyum, Turkey, 97% purity, 1 micron). The size of B powder was reduced by planetary milling using $ZrO_2$ balls (a diameter of 2 mm). The B powder and balls with a ratio of 1:20 were charged in a ceramic jar and then the jar was filled with toluene. The milling time was varied from 0 to 8 h. The milled B powders were mixed with Mg powder in the composition of (Mg+2B), and the powder mixtures were uniaxially pressed at 3 tons. The powder compacts were heat-treated at $700^{\circ}C$ for 1 h in flowing argon gas. Powder X-ray diffraction and FWHM (Full width at half maximum) were used to analyze the phase formation and crystallinity of $MgB_2$. The superconducting transition temperature ($T_c$) and $J_c$ of $MgB_2$ were measured using a magnetic property measurement system (MPMS). It was found that $B_2O_3$ was formed by B milling and the subsequent drying process, and the volume fraction of $B_2O_3$ increased as milling time increased. The $T_c$ of $MgB_2$ decreased with increasing milling time, which was explained in terms of the decreased volume fraction of $MgB_2$, the line broadening of $MgB_2$ peaks and the formation of $B_2O_3$. The $J_c$ at 5 K increased with increasing milling time. The $J_c$ increase is more remarkable at the magnetic field higher than 3 T. The $J_c$ at 5 K and 4 T was the highest as $4.37{\times}10^4A/cm^2$ when milling time was 2 h. The $J_c$ at 20 K also increased with increasing milling time. However, The $J_c$ of the samples with the prolonged milling for 6 and 8 h were lower than that of the non-milled sample.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.791-793
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• 2009

Escherichia coli RNase P is composed of a large RNA subunit (M1 RNA) and a small protein subunit (C5 protein). Since both subunits are assembled in a 1:1 ratio, expression of M1 RNA and C5 protein should be coordinately regulated for RNase P to be efficiently synthesized in the cell. However, it is not known yet how the coordination occurs. In this study, we investigated how overexpression of C5 protein affects expression of the rnpB gene encoding M1 RNA, using a lysogenic strain, which carries an rnpB-lacZ transcription fusion. Primer extension analysis of rnpB-lacZ fusion transcripts showed that the overexpression of C5 protein increased the amount of the fusion transcripts, suggesting that rnpB expression increases with the increase of intracellular level of C5 protein.