• Journal of the Korean Mathematical Society
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• v.46 no.5
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• pp.1027-1040
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• 2009

A ring R is called IFP, due to Bell, if ab = 0 implies aRb = 0 for a, b $\in$ R. Huh et al. showed that the IFP condition is not preserved by polynomial ring extensions. In this note we concentrate on a generalized condition of the IFPness that can be lifted up to polynomial rings, introducing the concept of quasi-IFP rings. The structure of quasi-IFP rings will be studied, characterizing quasi-IFP rings via minimal strongly prime ideals. The connections between quasi-IFP rings and related concepts are also observed in various situations, constructing necessary examples in the process. The structure of minimal noncommutative (quasi-)IFP rings is also observed.

• Acta Via Serica
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• v.5 no.1
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• pp.121-152
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• 2020

The article is a critical examination of the political developments in Armenia since the 'Velvet Revolution' of April-May 2018, when, on the wave of massive protests against the ruling regime, new young forces came to power raising amongst broad segments of population enormous enthusiasm and hopes about radical reforms that would lead to profound transformations in the political and socio-economic spheres. It contains a thorough analysis of underlying political processes in the country in an attempt to answer a number of topical questions, so important to get a deeper understanding of the situation in Armenia and in the South Caucasus region. Based on the analysis of the new authorities' performance against the acknowledged benchmarks and standards of democracy consolidation, such as: separation of powers, independence of the judiciary, good governance, transitional justice the author comes to the conclusion that they failed to achieve any breakthrough in the above-mentioned fields. On the contrary, as demonstrated by concrete examples, what occurred in Armenia was not a revolution but a mere regime change under the leadership of Prime Minister Pashinyan, who gradually has concentrated in his hands executive, legislative, and quasi-totality of the judicial branch of power.

• Communications of the Korean Mathematical Society
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• v.39 no.1
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• pp.45-58
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• 2024

Let R be a commutative ring with identity. If the nilpotent radical N il(R) of R is a divided prime ideal, then R is called a ϕ-ring. Let R be a ϕ-ring and S be a multiplicative subset of R. In this paper, we introduce and study the class of nonnil-S-coherent rings, i.e., the rings in which all finitely generated nonnil ideals are S-finitely presented. Also, we define the concept of ϕ-S-coherent rings. Among other results, we investigate the S-version of Chase's result and Chase Theorem characterization of nonnil-coherent rings. We next study the possible transfer of the nonnil-S-coherent ring property in the amalgamated algebra along an ideal and the trivial ring extension.

• Korean Journal of Head & Neck Oncology
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• v.16 no.1
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• pp.46-51
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• 2000

Objectives: Primary malignant tumors in the salivary glands are relatively rare. Because of the rarity and the different histopathologic patterns, it is difficult to establish a uniform treatment strategy. The prime treatment of salivary gland malignancy is the surgery, but the role of radiotherapy has been under debate. Radiation therapy combined with conservative surgical procedures may be as successful and perhaps more rational treatment than radical surgery alone. The aim of this study is to evaluate clinical pattern, incidence, treatment modality and outcome of the salivary gland maligancy. Materials and Methods: The medical records of 32 patients with malignant neoplasm of salivary gland who treated at the Keimyung university Dongsan hospital were analyzed retrospectively. Results: The overall 5 year survival rate was 77.9% stage I : 100%, stage II : 75%, stage III : 66.7%, stage IV : 55.6%). The 5 year survival rate according to tumor grade was 100% in low grade malignancy, 71.8% in high grade malignancy. The 5 year survival rate according to treatment modalities was as follows: Surgery only group was 83.3%, combined treatment group with surgery and posoperative radiation was 74.6%. Conclusion: The factors affecting prognosis is variable, but the stage at the time of diagnosis, site of lesion, tumor grade, histologic subtype were important factors. Surgery was the prime treatment tool and postoperative radiotherapy was also imperative in higher stage patient, high grade tumor, or patients with positive surgical margin.

• Journal of the Korean Mathematical Society
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• v.51 no.1
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• pp.87-98
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• 2014

Let R be a commutative ring with identity and M an R-module. In this paper, we associate a graph to M, say ${\Gamma}(M)$, such that when M = R, ${\Gamma}(M)$ is exactly the classic zero-divisor graph. Many well-known results by D. F. Anderson and P. S. Livingston, in [5], and by D. F. Anderson and S. B. Mulay, in [6], have been generalized for ${\Gamma}(M)$ in the present article. We show that ${\Gamma}(M)$ is connected with $diam({\Gamma}(M)){\leq}3$. We also show that for a reduced module M with $Z(M)^*{\neq}M{\backslash}\{0\}$, $gr({\Gamma}(M))={\infty}$ if and only if ${\Gamma}(M)$ is a star graph. Furthermore, we show that for a finitely generated semisimple R-module M such that its homogeneous components are simple, $x,y{\in}M{\backslash}\{0\}$ are adjacent if and only if $xR{\cap}yR=(0)$. Among other things, it is also observed that ${\Gamma}(M)={\emptyset}$ if and only if M is uniform, ann(M) is a radical ideal, and $Z(M)^*{\neq}M{\backslash}\{0\}$, if and only if ann(M) is prime and $Z(M)^*{\neq}M{\backslash}\{0\}$.

• Journal of the Korean Mathematical Society
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• v.60 no.6
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• pp.1233-1254
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• 2023

We introduce two subclasses of abelian McCoy rings, so-called π-CN-rings and π-duo rings, and systematically study their fundamental characteristic properties accomplished with relationships among certain classical sorts of rings such as 2-primal rings, bounded rings etc. It is shown that a ring R is π-CN whenever every nilpotent element of index 2 in R is central. These rings naturally generalize the long-known class of CN-rings, introduced by Drazin [9]. It is proved that π-CN-rings are abelian, McCoy and 2-primal. We also show that, π-duo rings are strongly McCoy and abelian and also they are strongly right AB. If R is π-duo, then R[x] has property (A). If R is π-duo and it is either right weakly continuous or every prime ideal of R is maximal, then R has property (A). A π-duo ring R is left perfect if and only if R contains no infinite set of orthogonal idempotents and every left R-module has a maximal submodule. Our achieved results substantially improve many existing results.

• Journal of Life Science
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• v.27 no.12
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• pp.1470-1478
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• 2017

The aim of this study was to investigate biological activity and biochemical properties of extracts from Bacillus subtilis-fermented silkworm (Bombyx mori L., SP) powder of different origin (Buan, Namwon, and Boeun). An additional aim was to determine the inhibition of cancer cell (B16-F10, HT-29, LNcaP, and MCF-7) proliferation and nitric oxide (NO) production from lipopolysaccharide (LPS)-induced RAW264.7 cells. Biological activities (${\alpha},{\alpha}^{\prime}$-diphenyl-${\beta}$-picrylhydrazyl [DPPH], free radical scavenging activity, fibrinolytic activity, antiproliferation activity, and anti-inflammatory activity) and biochemical properties (compositional amino acid contents, and mineral contents) were examined in water extracts from silkworm powder and B. subtilis-fermented silkworm powder. The highest amino acid contents were detected in Buan silkworm powder (BU). After fermented, the highest contents were found in B. subtilis-fermented Buan silkworm powder (BBO). The major minerals detected were K, Ca, and Mg. Rates of these minerals, especially those of Na increased after fermented. DPPH radical scavenging activity and fibrinolytic activity were stronger in the fermented group than non-fermented group. DPPH radical scavenging activity and fibrinolytic activity were highest in the extract from BBO. The inhibition activities of LNcaP and MCF-7 cells viability were significantly decreased in the BBO, and there was no inhibition activity in other cancer cells (B16-F10 and HT-29). An SRB assay of the cell viability of RAW 264.7 cells exposed to extracts of silkworm powder and B. subtilis-fermented silkworm powder revealed no toxicity in any of the groups. Compared with the LPS-treated group, the biggest reduction in NO production was detected in the BBO group. Based on these results, extracts from Boeun silkworm powder fermented with B. subtilis could be a candidate material as a dietary supplement for use in healthy functional foods.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.77-77
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• 2016

Thin films synthesized by plasma processes have been widely applied in a variety of industrial sectors. The structure control of thin film is one of prime factor in most of these applications. It is well known that the structure of this film is closely associated with plasma parameters and species of plasma which are electrons, ions, radical and neutrals in plasma processes. However the precise control of structure by plasma process is still limited due to inherent complexity, reproducibility and control problems in practical implementation of plasma processing. Therefore the study on the fundamental physical properties that govern the plasmas becomes more crucial for molecular scale control of film structure and corresponding properties for new generation nano scale film materials development and application. The thin films are formed through nucleation and growth stages during thin film depostion. Such stages involve adsorption, surface diffusion, chemical binding and other atomic processes at surfaces. This requires identification, determination and quantification of the surface activity of the species in the plasma. Specifically, the ions and neutrals have kinetic energies ranging from ~ thermal up to tens of eV, which are generated by electron impact of the polyatomic precursor, gas phase reaction, and interactions with the substrate and reactor walls. The present work highlights these aspects for the controlled and low-temperature plasma enhanced chemical vapour disposition (PECVD) of Si-based films like crystalline Si (c-Si), Si-quantum dot, and sputtered crystalline C by the design and control of radicals, plasmas and the deposition energy. Additionally, there is growing demand on the low-temperature deposition process with low hydrogen content by PECVD. The deposition temperature can be reduced significantly by utilizing alternative plasma concepts to lower the reaction activation energy. Evolution in this area continues and has recently produced solutions by increasing the plasma excitation frequency from radio frequency to ultra high frequency (UHF) and in the range of microwave. In this sense, the necessity of dedicated experimental studies, diagnostics and computer modelling of process plasmas to quantify the effect of the unique chemistry and structure of the growing film by radical and plasma control is realized. Different low-temperature PECVD processes using RF, UHF, and RF/UHF hybrid plasmas along with magnetron sputtering plasmas are investigated using numerous diagnostics and film analysis tools. The broad outlook of this work also outlines some of the 'Grand Scientific Challenges' to which significant contributions from plasma nanoscience-related research can be foreseen.

• Journal of Life Science
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• v.28 no.7
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• pp.827-834
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• 2018

In this study, the biological activities of aqueous, ethanol, and methanol extracts of larvae of the edible insect Protaetia brevitarsis seulensis, fermented using several kinds of microorganisms, were tested in in vitro experimental models. Six effective microorganisms were used for fermentation, namely Lactobacillus plantarum JBMI F3, Lactobacillus plantarum JBMI F5, Lactobacillus gasseri Ba9, Aspergillus kawachii KCCM 32819, Saccharomyces cerevisiae KACC 93023, and Bacillus subtilis KACC 91157. Biological activities (${\alpha},{\alpha}^{\prime}-diphenyl-{\beta}-picrylhydrazyl$ [DPPH] free radical scavenging activity, reducing power, and fibrinolytic activity), and biochemical properties (phenolic compounds and flavonoids) were examined in aqueous, ethanol, and methanol extracts from P. brevitarsis seulensis powder and fermented P. brevitarsis seulensis powder. The total phenolic compounds and flavonoid contents were highest in the aqueous extract of B. subtilis-fermented P. brevitarsis seulensis powder. DPPH radical scavenging activity and reducing power were stronger in the fermented group than the nonfermented group. Fibrinolytic activity were highest in the extract from B. subtilis-fermented P. brevitarsis seulensis powder. The ${\alpha}-amylase$ activity in starch was higher in the fermented group than the nonfermented group, but there was no significant difference. These results provide basic data to understand the biological activities of bioactive materials derived from fermented P. brevitarsis seulensis larvae for the development of functional foods.

• Bulletin of the Korean Mathematical Society
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• v.40 no.2
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• pp.223-234
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• 2003

This note contains the following results for a ring A : (1) A is simple Artinian if and only if A is a prime right YJ-injective, right and left V-ring with a maximal right annihilator ; (2) if A is a left quasi-duo ring with Jacobson radical J such that $_{A}$A/J is p-injective, then the ring A/J is strongly regular ; (3) A is von Neumann regular with non-zero socle if and only if A is a left p.p.ring containing a finitely generated p-injective maximal left ideal satisfying the following condition : if e is an idempotent in A, then eA is a minimal right ideal if and only if Ae is a minimal left ideal ; (4) If A is left non-singular, left YJ-injective such that each maximal left ideal of A is either injective or a two-sided ideal of A, then A is either left self-injective regular or strongly regular : (5) A is left continuous regular if and only if A is right p-injective such that for every cyclic left A-module M, $_{A}$M/Z(M) is projective. ((5) remains valid if 《continuous》 is replaced by 《self-injective》 and 《cyclic》 is replaced by 《finitely generated》. Finally, we have the following two equivalent properties for A to be von Neumann regula. : (a) A is left non-singular such that every finitely generated left ideal is the left annihilator of an element of A and every principal right ideal of A is the right annihilator of an element of A ; (b) Change 《left non-singular》 into 《right non-singular》in (a).(a).