• Korean Journal of Microbiology
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• v.48 no.4
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• pp.319-324
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• 2012

In this study, we investigated molecular divergences and phylogenetic characteristics of the 16S ribosomal RNA (rRNA) and RNA polymerase beta subunit (rpoB) gene sequences from the order Oscillatoriales (Cyanobacteria). The rpoB of Oscillatoriales showed higher genetic divergence when compared with those of 16S rRNA (p-distance: rpoB=0.270, 16S=0.109), and these differences were statistically significant (Student t-test, p<0.001). Phylogenetic trees of 16S rRNA and rpoB were generally compatible; however, rpoB tree clearly separated the compared Oscillatoriales taxa, with higher phylogenetic resolution. In addition, parsimony analyses showed that rpoB gene evolved 2.40-fold faster than 16S rRNA. These results suggest that the rpoB is a useful gene for the molecular phylogenetics and species discrimination in the order Oscillatoriales.

• Communications of the Korean Mathematical Society
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• v.37 no.2
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• pp.337-345
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• 2022

Let R ⊆ T be an extension of a commutative ring and S ⊆ R a multiplicative subset. We say that (R, T) is an S-accr (a commutative ring R is said to be S-accr if every ascending chain of residuals of the form (I : B) ⊆ (I : B²) ⊆ (I : B³) ⊆ ⋯ is S-stationary, where I is an ideal of R and B is a finitely generated ideal of R) pair if every ring A with R ⊆ A ⊆ T satisfies S-accr. Using this concept, we give an S-version of several different known results.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.296-302
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• 2010

Microcystis (Cyanobacteria, Chroococcales) is one of the green tide-causing organisms in freshwaters, and some species produce microcystin that is hepatotoxin. In the aspects of freshwater quality controls and health concerns, therefore it is necessary to manage the harmful organisms. In the present study, RNA polymerase beta subunit (rpoB) gene sequences of Microcystis were determined and characterized in order to use a potential marker for the molecular detections of the species. Microcystis rpoB showed high divergences of DNA similarity and genetic distances when compared with those of 16S rRNA, and the molecular differences were statistically significant (Student t-test, p<0.05). Parsimony analyses showed the rpoB gene evolves more than 2-fold faster than 16S rRNA. In addition, phylogeny of the rpoB gene separated each M. aeruginosa strain more clearly compared with a 16S rRNA tree. This study found that the order Chroococcales, including Microcystis, has approximately two rRNA operons and single copy of the rpoB gene in their chromosomes. These results suggest that the rpoB gene is a useful marker for the molecular phylogenetics and the detection of Microcystis.

• Bulletin of the Korean Mathematical Society
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• v.22 no.2
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• pp.121-126
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• 1985

D.K. Harrison [5] has shown that if R and S are fields of characteristic different from 2, then two Witt rings W(R) and W(S) are isomorphic if and only if W(R)/I(R)$^{3}$ and W(S)/I(S)$^{3}$ are isomorphic where I(R) and I(S) denote the fundamental ideals of W(R) and W(S) respectively. In [1], J.K. Arason and A. Pfister proved a corresponding result when the characteristics of R and S are 2, and, in [9], K.I. Mandelberg proved the result when R and S are commutative semi-local rings having 2 a unit. In this paper, we prove the result when R and S are 2-fold full rings. Throughout this paper, unless otherwise specified, we assume that R is a commutative ring having 2 a unit. A quadratic space (V, B, .phi.) over R is a finitely generated projective R-module V with a symmetric bilinear mapping B: V*V.rarw.R which is nondegenerate (i.e., the natural mapping V.rarw.Ho $m_{R}$ (V, R) induced by B is an isomorphism), and with a quadratic mapping .phi.:V.rarw.R such that B(x,y)=(.phi.(x+y)-.phi.(x)-.phi.(y))/2 and .phi.(rx)= $r^{2}$.phi.(x) for all x, y in V and r in R. We denote the group of multiplicative units of R by U(R). If (V, B, .phi.) is a free rank n quadratic space over R with an orthogonal basis { $x_{1}$, .., $x_{n}$}, we will write < $a_{1}$,.., $a_{n}$> for (V, B, .phi.) where the $a_{i}$=.phi.( $x_{i}$) are in U(R), and denote the space by the table [ $a_{ij}$ ] where $a_{ij}$ =B( $x_{i}$, $x_{j}$). In the case n=2 and B( $x_{1}$, $x_{2}$)=1/2, we reserve the notation [ $a_{11}$, $a_{22}$] for the space.the space.e.e.e.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1429-1435
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• 2002

The absolute stereochemistry of tetrin B (1), an antifungal antibiotic isolated from a soil actinomycete was determined by applying Rychnovsky analysis, the modified Mosher method, and CD exciton chirality to be 4R, 5R, 7S, 9R, 11S, 12R, 13S, 15R, 24S, and 25R.

• Korean Journal of Mathematics
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• v.27 no.4
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• pp.949-968
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• 2019

In this work, we characterize some matrix classes concerning the Binomial sequence spaces b^r,s_∞ and b^r,s_p, where 1 ≤ p < ∞. Moreover, by using the notion of Hausdorff measure of noncompactness, we characterize the class of compact matrix operators from b^r,s₀, b^r,s_c and b^r,s_∞ into c₀, c and ℓ_∞, respectively.

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.113-117
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• 1993

Good yield synthetic routes for the production of new B-alkyl-dithiaborane clusters are reported. The syntheses of the B-alkyl-dithiaboranes are based on the use of Fischer-type carbene reagents to activate the B-H bonds of dithiaborane for alkyl-addition reactions and are the first examples of transition-mediated reactions of dithiaborane to be reported. Thus, reactions employing arachno-$S_2B_7H_8$- and $(CO)_5M{C(R_1)R_2}$ (M = Cr, W; $R_1 = CH_3,\;C_6H_5;\; R_2 = OCH_3,\;SC_6H_5)$ were found to yield the intermidiate anions I, $[(CO)_5M{C(R_1)R_2S_2B_7H_8}]^-$, which upon protonation gave the corresponding neutral, air-sensitive cluster arachno-4-$RCH_2-6,8-S_2B_7H_8(R=CH_3,\;IIa;\;C_6H_5,\;IIb)$ range from 30 to 35% yield. Complexes IIa and IIb are isoelectronic with arachno-6,8-$S_2B_7H_9$ and, on the basis of the spectroscopic data, are proposed to adopt a similar arachno cage geometry in which an $RCH_2$ units are substituted to 4 position boron atom of the arachno-6,8-$S_2B_7H_9$.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.480-488
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• 2016

Soil microbes are widely well known to play an important role for sustainable agriculture in terms of crop healthy cultivation and environmental conservation. In this context, the distributional characteristics of soil microbes according to cropping systems were investigated under rice (R)-rice (R), rice (R)-barley (B)-rice (R), and soybean (S)-barley (B)-soybean (S) cropping condition to get basic informations for sustainable agriculture, where barley was grown for winter, in mid-mountainous loam paddy located at the altitude of 285 m above sea level in Sangju area from 2014 to 2015. Estimating from microbial communities by fatty acid methyl ester (FAME) method, a total biomass of bacteria, actinomycetes, and fungi in R-B-R plot was 37% and 40% higher than that in S-B-S and R-R plots, respectively (p < 0.05). In especial, bacteria and fungi were more in R-B-R plot than those in any other ones. B. japonicum, AMF, and mesophilic Bacillus sp. were also greater in S-B-S plot than those. In the community distribution, however, bacteria and actinomycetes showed comparatively high values in S-B-S plot relative to either R-R or R-B-R plot including rice, in which fungi outstanding. In the correlation between microbial biomass and soil properties changed by the cropping, bacteria was positively correlated with C:N ratio; actinomycetes with exchangeable Ca; fungi with available $P_2O_5$ (p < 0.05). While these microbes showed negative response to water stable aggregates of soil.

• BMB Reports
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• v.51 no.11
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• pp.602-607
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• 2018

Aberrant expression of microRNAs (miRNAs) plays important roles in carcinogenesis and tumor progression. However, the expression and biological role of miR-301b in triple-negative breast cancer (TNBC) remains unclear. Here we aimed to evaluate the roles and mechanisms of miR-301b in TNBC cells. miR-301b expression was assessed in TNBC specimens and cell lines by quantitative Real-Time PCR (qRT-PCR). TNBC cells were transfected with miR-301b mimics, inhibitors or Cylindromatosis (CYLD) small interfering RNA (siRNA) using Lipofectamine 2000. The functional roles of miR-301b were determined by cell proliferation, colony formation, and apoptosis assays. Western blots and qRT-PCR were used to measure the expression of mRNAs and proteins in the cells. We found that miR-301b was upregulated in TNBC specimens and cell lines. Overexpression of miR-301b promoted cell proliferation in TNBC cells, while inhibited the apoptosis induced by 5-FU. CYLD was downregulated by miR-301b at both mRNA and protein levels in TNBC cells. Dual-luciferase report assay confirmed that miR-301b downregulated CYLD by direct interaction with the 3'-untranslated region(3'-UTR) of CYLD mRNA. $NF-{\kappa}B$ activation was mechanistically associated with miR-301b-mediated downregulation of CYLD. However, inhibition of miR-301b reversed all the effects of miR-301b. In conclusion, miR-301b plays an oncogenic role in TNBC possibly by downregulating CYLD and subsequently activating $NF-{\kappa}B$ p65, and this may provide a novel therapeutic approach for TNBC.

• Bulletin of the Korean Mathematical Society
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• v.59 no.3
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• pp.643-657
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• 2022

Let R be a ring and S a multiplicative subset of R. An R-module T is called u-S-torsion (u-always abbreviates uniformly) provided that sT = 0 for some s ∈ S. The notion of u-S-exact sequences is also introduced from the viewpoint of uniformity. An R-module F is called u-S-flat provided that the induced sequence 0 → A ⊗_R F → B ⊗_R F → C ⊗_R F → 0 is u-S-exact for any u-S-exact sequence 0 → A → B → C → 0. A ring R is called u-S-von Neumann regular provided there exists an element s ∈ S satisfying that for any a ∈ R there exists r ∈ R such that sα = rα². We obtain that a ring R is a u-S-von Neumann regular ring if and only if any R-module is u-S-flat. Several properties of u-S-flat modules and u-S-von Neumann regular rings are obtained.