• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1767-1770
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• 2005

Novel 1',4'-dimethyl branched carbocyclic nucleosides were synthesized from acetol. The 4'-methyl group was installed via a Claisen rearrangement reaction, and the carbonyl addition of methylmagnesium bromide was used to introduce the 1'-methyl group. The coupling of nucleosidic bases and desilylation was used to produce a series of novel nucleosides.

• Journal of the Korean Mathematical Society
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• v.35 no.4
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• pp.961-980
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• 1998

The cyclically presented groups which arise as fundamental groups of cyclic branched coverings of the knot $5_2$ are studied. The fundamental polyhedra for these groups are described. Moreover the cyclic covering manifolds are obtained in terms of Dehn surgery and as two-fold branched coverings of the 3-sphere.

• Journal of the Korean Mathematical Society
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• v.46 no.6
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• pp.1119-1137
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• 2009

We construct a family of hyperbolic 3-manifolds by pairwise identifications of faces in the boundary of certain polyhedral 3-balls and prove that all these manifolds are cyclic branched coverings of the 3-sphere over certain family of links with two components. These extend some results from [5] and [10] concerning with the branched coverings of the whitehead link.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.5
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• pp.29-38
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• 1992

This paper describes the general formulation for the in-plane longitudinal and flexural coupled free vibration analysis of a branched structure. The branched structure, which is mainly found in machine tools, pipeline systems and so on, has some crooked parts and subsystems. And it modeled as a distributed mass system. The superiority of the present method to the transfer matrix method in the computation accuracy and speed was confirmed by the numerical computation results. Moreover, we comfirmed that boundary and intermediate conditions have been controlled by the spring constants.

• Archives of Pharmacal Research
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• v.28 no.10
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• pp.1105-1110
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• 2005

Novel anomeric branched carbocyclic nucleosides were synthesized from 1,3-dihydroxy acetone. 4'-Hydroxymethyl was installed by [3,3]-sigmatropic rearrangement reaction and 1'-methyl group was introduced by carbonyl addition of methylmagnesium bromide. The coupling of nucleosidic bases and desilylation afforded a series of novel nucleosides. The synthesized compounds $16{\~}19$ were evaluated for their antiviral activity against HIV-1, HSV-1, HSV-2, and EMCV. Compounds 16 and 19 exhibit toxicity non-related to any anti-HIV-1 activity.

• Archives of Pharmacal Research
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• v.26 no.12
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• pp.1109-1116
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• 2003

A series of 3'- and 4'-branched carbocyclic nucleosides 25, 26, 27, 28, 29 and 30 were synthesized starting from simple acyclic ketone derivatives. The construction of the required quaternary carbon was made using a [3,3]-sigmatropic rearrangement. In addition, the installation of a methyl group in the 3'-position was accomplished using a Horner-Wadsworth-Emmons (HWE) reaction with triethyl 2-phosphonopropionate. Bis-vinyl was successfully cyclized using a Grubbs' catalyst (Ⅱ). Natural bases (adenine, cytosine, uracil) were efficiently coupled with the use of a Pd(0) catalyst.

• East Asian mathematical journal
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• v.38 no.1
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• pp.107-127
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• 2022

In this paper, we discuss the relationship between doubly-pointed Heegaard diagrams of (1, 1)-knots in lens spaces and Dunwoody 3-manifolds, and then give explicit representations of n-fold cyclic branched coverings of all (1, 1)-knots in S³ up to 10 crossings in Rolfsen's knot table as Dunwoody 3-manifolds.

• Journal of the Korean Electrochemical Society
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• v.16 no.2
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• pp.81-84
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• 2013

We demonstrate rutile $TiO_2$ branched nanostructure ($TiO_2$-BN) electrodes synthesized by seeding method for enhanced lithium intercalation properties. The morphology and crystalline nature of the $TiO_2$-BN were clearly observed by field-emission transmission electron microscopy and fast Fourier transform pattern. The $TiO_2$-BN electrodes showed excellent capacity and high rate performance. The improved lithium-ion intercalation properties of the $TiO_2$- BN may be attributed to relatively large specific surface area and short transport distance of the branched nanostructure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.461-464
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• 2000

A branched crack in a semi-infinite plate under tension and bending moment is considered. Intensity factors of the stress and moment for the branched crack are evaluated. The stress intensity factors are obtained by using the finite element method and the J-based mutual integral. The moment intensity factors are calculated by extrapolating the values of the moment near the crack tip. Approximate expressions are also obtained as functions of the branched crack length and branching angle.

• BMB Reports
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• v.28 no.1
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• pp.12-16
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• 1995

The branched-chain ${\alpha}$-keto acid dehydrogenase (BCKAD) complex is a rate limiting enzyme which catalyzes the oxidative decarboxylation of branched-chain ${\alpha}$-keto acids. Numerous studies have suggested that BCKAD is subject to covalent modification in vitro via phosphorylation and dephosphorylation, which are catalyzed by a specific kinase and phosphatase, respectively. The biggest difficulty in the assay of BCKAD activity is to arrest the interconversion between the active and inactive forms. BCKAD activity was determined from fresh rat heart and liver tissues using homogenizing and assay buffers containing inhibitors of phosphatase and kinase. The results suggest that a radiochemical assay using ${\alpha}$-keto[1-$^{14}C$]-isovalerate as a substrate for the enzyme can be applied as a reliable method to determine in vitro enzyme activity with arrested interconversion between the active and inactive forms of the BCKAD complex.