• 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 Nutrition and Health
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• v.38 no.5
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• pp.335-343
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• 2005

Rodent models have been used to study the anticarcinogenic properties of the soy isoflavones, particularly genistein, but there is little information regarding the pharmacokinetics of the absorption and excretion of genistein. In this study, rats were given a single oral dose of genistein (20 mg/kg body wt) or an equivalent dose as Myougjoonamul-kong and Myoungjoonamul soy sprouts. Concentrations of genistein were measured in plasma, urine and feces at intervals up to 48hr after dosing. Maximum peak of plasma genistein concentration is 8 hr after dosing, and its concentration is 13.2, 7.4mol/L in soy and soy sprout-treated rats, respectively. In pure genistein treated rats, maximum peak of plasma genistein concentration is 2hr after dosing (5.7 mol/L). The percentage of dose recovered in urine over 48hr was not different between groups ($21.2\%$ soy treated; $18.2\%$ soy sprout treated; $16.1\%$ pure genistein treated). There were no significant differences between groups in the recovery of genistein in feces ($19.5\%,\;7.5\%\;and\;15.7\%$ of doses, respectively). $6.9\%\;and\;6.07\%$ of the daidzein from the soy and soy sprout treated was recovered in the feces.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.467-472
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• 2003

Optically pure α-mono- and α, α-disubstituted β-amino acids were conveniently prepared in four steps and in 27-40% overall yields from the correspondingly substituted racemic β-hydroxy acids that can be readily obtained from diethyl malonate. In the synthesis, (S)-phenylethylamine has been used as a resolving agent and as a source of the amino group in the β-amino acids.

• Bulletin of the Korean Mathematical Society
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• v.54 no.4
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• pp.1281-1291
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• 2017

Let R be a strongly 2-primal ring and I a proper ideal of R. Then there are only finitely many prime ideals minimal over I if and only if for every prime ideal P minimal over I, the ideal $P/{\sqrt{I}}$ of $R/{\sqrt{I}}$ is finitely generated if and only if the ring $R/{\sqrt{I}}$ satisfies the ACC on right annihilators. This result extends "D. D. Anderson, A note on minimal prime ideals, Proc. Amer. Math. Soc. 122 (1994), no. 1, 13-14." to large classes of noncommutative rings. It is also shown that, a 2-primal ring R only has finitely many minimal prime ideals if each minimal prime ideal of R is finitely generated. Examples are provided to illustrate our results.

• Journal of applied mathematics & informatics
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• v.35 no.1_2
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• pp.25-32
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• 2017

Let G be a graph and k is a positive integer. Hammack and Livesay in [The inner power of a graph, Ars Math. Contemp., 3 (2010), no. 2, 193-199] introduced a new graph operation $G^{(k)}$, called the $k^{th}$ inner power of G. In this paper, it is proved that if G is bipartite then $G^{(2)}$ has exactly three components such that one of them is bipartite and two others are isomorphic. As a consequence the edge frustration index of $G^{(2)}$ is computed based on the same values as for the original graph G. We also compute the first and second Zagreb indices and coindices of $G^{(2)}$.

• Nonlinear Functional Analysis and Applications
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• v.27 no.4
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• pp.807-812
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• 2022

The need for smoothness measures emerged by mathematicians working in the fields of approximation theory, functional analysis and real analysis. In the present paper, a new version of generalized modulus of smoothness is studied. The aim of defining that modulus, is to find the degree of best L_p functions approximation via trigonometric polynomials. We benefit from Jackson integrals to arrive to the essential approximation theorems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.169-176
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• 2019

In the present study, a CFD/DSMC hybrid method performed by a coupled analysis between the CFD method and the DSMC method was developed to obtain the flow information on the rarefied gas flows effectively. Flow simulations around the high speed vehicles on the transition flow regimes were conducted by using the developed method. The FRESH-FX vehicle made of cone and cylinder shapes was considered for the simulations. The results of the hybrid method were compared with the results of the pure CFD and the pure DSMC method to confirm the reliability and efficiency of the hybrid method. It was found that the gradient and the intensity of the shock waves were weakened due to the relatively low density on the transition flow regime. It was confirmed that the results of the hybrid analysis were different to those of the pure CFD analysis and almost identical to those of the pure DSMC analysis. In addition, the computational time of the hybrid method was reduced than that of the pure DSMC method. As a result, it was obtained that the validity and the efficiency of the CFD/DSMC hybrid method.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.575-579
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• 2023

In this work, pure W and W-0.5wt%HfC alloy (WHC05) were fabricated by sintering and hot-rolling following the same processing route. After exposing to a high flux deuterium plasma irradiation with the D⁺ flux to three fluences of 6.00 × 10²⁴, 2.70 × 10²⁵ and 7.02 × 10²⁵ D/m², the evolution of surface morphology, deuterium retention and hardening behaviors in pure W and WHC05 has been studied. The SEM results show the formation of D blisters on the irradiated area, and with the increase of D implantation, the size of these blisters increases from 200 ~ 500 nm (2.70 × 10²⁵ D/m²) to 1 ~ 2 ㎛ (7.02 × 10²⁵ D/m²) in WHC05 and from 1 ~ 2 ㎛ (2.70 × 10²⁵ D/m²) to > 3 ㎛ (7.02 × 10²⁵ D/m²) in pure W, respectively. A higher D retention and obvious hardening are observed in pure W than that of the WHC05 alloy, indicating an improve radiation resistance in WHC05 compared to pure W.

• Journal of Genetic Medicine
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• v.14 no.2
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• pp.71-74
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• 2017

Mutations in the DNA methyltransferase 1 gene (DNMT1) were reported to cause two phenotypes: OMIM 604121 and OMIM 614116. The first phenotype includes autosomal dominant cerebellar ataxia, deafness, and narcolepsy, which were reported to be caused by mutations in exon 21. The second phenotype includes hereditary sensory and autonomic neuropathy type 1E, which was suggested to be caused by mutations in exon 20 and 21. In this article, we report a novel heterozygous missense variant c.898A>C, p.(Lys300Gln) in exon 12 of DNMT1 in a young woman who presented with pure cerebellar ataxia. This report indicates that a mutation in exon 12 may lead to pure cerebellar ataxia. Another possibility is that the patient is currently in an early stage of the disease, and as the disease progresses, she will have more manifestations. To confirm or exclude this possibility, a subsequent follow-up study reporting the disease progression in this patient may be needed. Further reports of cases with the same mutation are needed to confirm the phenotype of this mutation.

• Phonetics and Speech Sciences
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• v.9 no.4
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• pp.77-89
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• 2017

This study investigates the phonetic meaning of clarity and turbidity(淸濁) that has been used in psychoacoustics, musicology, and linguistics in both the East and the West. With a view to clarifying the phonetic meaning of clarity and turbidity, this study conducts three perception tests. First, 34 subjects were asked to take one of Clear and Turbid by forced choice for 5 pure and complex tones, respectively, ranging from A2 to A6 differing by octave. Second, they were asked to select between the two choices for 25 pure and complex tones, respectively, ranging from A2 to A4 differing by semitone. Third, they were asked to opt for one of the two choices for 8 different vowels of different formant and fundamental frequencies. Results showed that there is a certain range of tone which is perceived as clear, that clarity level increases as fundamental frequency increases, and that pure tones have a higher level of clarity than complex ones, fundamental frequency being equal. Results also showed that vocal tract resonance enhances clarity level on the whole, and that lower vowels have a higher level of clarity than higher ones. This study is significant in that it demonstrates that clarity level is proportional to fundamental frequency and the first formant frequency, all else being equal.