Characterization in Terms of the NUX Rule of G-inserted Mutant Hammerhead Ribozymes with High Level of Catalytic Power

Kuwabara, Tomoko,Warashina, Masaki,Kato, Yoshio,Kawasaki, Hiroaki,Taira, Kazunari Korean Society for Biochemistry and Molecular Biol 2001 Journal of biochemistry and molecular biology Vol.34 No.1

Attempts using in vitro and in vivo selection procedures have been made to search for hammerhead ribozymes that have higher activities than the wild-type ribozyme and also to determine whether other sequences might be possible in the catalytic core of the hammerhead ribozyme. Active sequences selected in the past conformed broadly to the consensus core sequence except at A9, and no sequences were associated with higher activity than that of the hammerhead with the consensus core, an indication that the consensus sequence derived from viruses and virusoids is probably the optimal sequence [Vaish et al. (1997) Biochemistry 36, 6495-6501]. Recently, during construction of ribozyme expression vectors, we isolated a mutant hammerhead ribozyme, with an insertion of G between A9 and G10.1, that appeared to show significant activity [Kawasaki et al. (1996) Nucleic Acids Res. 24, 3010-3016; Kawasaki et al. (1998) Nature 393, 284-289]. We, therefore, characterized kinetic properties of the G-inserted mutant ribozymes in terms of the NUX rule. We demonstrate that the NUX rule is basically applicable to the G-inserted ribozymes and, more importantly, one type of G-inserted ribozyme was very active with $k_{cat}$, value of $6.4\;min^{-1}$ in 50 mM Tris-HCl (pH 8.0) and 10 mM $MgCl_2$ at $37^{\circ}C$.

Characterization in Terms of the NUX Rule of G - inserted Mutant Hammerhead Ribozymes with High Level of Catalytic Power

(Tomoko Kuwabara),(Masaki Warashina),(Yoshio Kato),(Hiroaki Kawasaki),(Kazunari Taira) 생화학분자생물학회 2001 BMB Reports Vol.34 No.1

Attempts using in vitro and in vivo selection procedures have been made to search for hammerhead ribozymes that have higher activities than the wild-type ribozyme and also to determine whether other sequences might be possible in the catalytic core of the hammerhead ribozyme. Active sequences selected in the past conformed broadly to the consensus core sequence except at A9, and no sequences were associated with higher activity than that of the hammerhead with the consensus core, an indication that the consensus sequence derived from viruses and virusoids is probably the optimal sequence [Vaish et al. (1997) Biochemistry 36, 6495-6501]. Recently, during construction of ribozyme expression vectors, we isolated a mutant hammerhead ribozyme, with an insertion of G between A9 and 610.1, that appeared to show significant activity [Kawasaki et at (1996) Nucleic Acids Res. 24, 3010-3016; Kawasaki et al. (1998) Nature 393, 284-289]. We, therefore, characterized kinetic properties of the G-inserted mutant ribozymes in terms of the NUX rule. We demonstrate that the NUX rule is basically applicable to the G-inserted ribozymes and, more importantly, one type of G-inserted ribozyme was very active with k_(cat), value of 6.4 min^(-1) in 50 mM Tris-HCl (pH 8.0) and 10 m1VI MgCl₂ at 37℃.

Clinical features, diagnosis, and outcomes of multisystem inflammatory syndrome in children associated with coronavirus disease 2019

Kwak, Ji Hee,Lee, Soo-Young,Choi, Jong-Woon,Korean Society of Kawasaki Diseasety of Pediatric Endocrinology (KSPE), The Korean Pediatric Society 2021 Clinical and Experimental Pediatrics (CEP) Vol.64 No.2

The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been spreading worldwide since December 2019. Hundreds of cases of children and adolescents with Kawasaki disease (KD)-like hyperinflammatory illness have been reported in Europe and the United States during the peak of the COVID-19 pandemic with or without shock and cardiac dysfunction. These patients tested positive for the polymerase chain reaction or antibody test for SARS-CoV-2 or had a history of recent exposure to COVID-19. Clinicians managing such patients coined new terms for this new illness, such as COVID-19-associated hyperinflammatory response syndrome, pediatric inflammatory multisystem syndrome temporally associated with COVID-19, or COVID-19-associated multisystem inflammatory syndrome in children (MIS-C). The pathogenesis of MIS-C is unclear; however, it appears similar to that of cytokine storm syndrome. MIS-C shows clinical features similar to KD, but differences between them exist with respect to age, sex, and racial distributions and proportions of patients with shock or cardiac dysfunction. Recommended treatments for MIS-C include intravenous immunoglobulin, corticosteroids, and inotropic or vasopressor support. For refractory patients, monoclonal antibody to interleukin-6 receptor (tocilizumab), interleukin-1 receptor antagonist (anakinra), or monoclonal antibody to tumor necrosis factor (infliximab) may be recommended. Patients with coronary aneurysms require aspirin or anticoagulant therapy. The prognosis of MIS-C seemed favorable without sequelae in most patients despite a reported mortality rate of approximately 1.5%.

A CLUSTER SURVEY AROUND THE UNIDENTIFIED EGRET SOURCES

KAWASAKI WATARU,TOTANI TOMONORI The Korean Astronomical Society 2005 Journal of The Korean Astronomical Society Vol.38 No.2

Based on optical galaxy data, we executed a systematic search for galaxy clusters around the 15 steady unidentified EGRET GeV gamma-ray sources in high Galactic-latitude sky ([b] > $30^{\circ}$). We found a strong correlation with 3.7$\sigma$ level between close cluster pairs (merging cluster candidates) and the unidentified EGRET sources, though, in contrast, no correlation with single clusters. This result implies that merging clusters of galaxies are a possible candidate for the origin of high galactic-latitude, steady unidentified EGRET gamma-ray sources.

均如鄕歌 解讀을 위한 漢文 資料의 體系的 對照와 巨視的 接近

Kawasaki Keigo 구결학회 2012 구결연구 Vol.29 No.-

均如鄕歌에는 對應하는 漢文 資料, 즉 崔行歸의 漢譯詩와 『華嚴經』의 「普賢行願品」이 존재한다. 이들은 틀림없이 均如鄕歌 解讀에 있어서 一次的으로 철저하게 검토되어야 하는 자료일 것이다. 본고의 一次的인 목적은, 均如鄕歌와 이들 漢文 資料의 對應 關係를 자세히 검토하여, 그것을 체계적으로 기술함으로써, 이 對應 關係가 종래 일반적으로 생각되었던 것보다 더 세밀하게 잘 對應되어 있음을 지적하는 데에 있다. 또한 ①그 對應 關係와 ②文脈, 그리고 ③均如鄕歌 內的으로 얻을 수 있는 언어적 근거 등을 주된 근거로 삼아, 새로 지적될 만한 사실이나 생각해야 할 문제 등을 지적함으로써, ‘巨視的 接近’의 필요성과 유효성을 구체적으로 보이는 것을 二次的인 목적으로 삼고자 한다. 이 노래는 결코 “意味만 通하면 되는” 정도의 노래는 아니라, 민중들의 입에서 입으로 퍼지고, 왕왕 담벼락에 쓰이기도 하고, 千年 후인 오늘날까지 전해질만한 노래였던 것이다. 우리는 결코 難解하고 曖昧模糊한 解讀에 만족할 수는 없을 것이다. 마치 “현대 일본어를 번역한 듯한” 깔끔하고 자연스럽고 잘 다듬어진 明確한 현대어로서 번역될 것을 기대해야 하는 것은 아닐까.

Review: achieving superplastic properties in ultrafine-grained materials at high temperatures

Kawasaki, Megumi,Langdon, Terence G. Springer-Verlag 2016 JOURNAL OF MATERIALS SCIENCE - Vol.51 No.1

<P>The mechanisms of superplasticity occurring in conventional materials, having grains sizes of the order of a few microns, are now understood reasonably well. However, very recent advances in the processing of ultrafine-grained (UFG) metals have provided an opportunity to extend the understanding of flow behavior to include UFG materials with submicrometer grain sizes. In practice, processing through the application of severe plastic deformation (SPD), as in equal-channel angular pressing (ECAP) and high-pressure torsion (HPT), has permitted the fabrication of relatively large samples having UFG microstructures. Since the occurrence of superplastic flow generally requires a grain size smaller than similar to 10 mu m, it is reasonable to anticipate that materials processed by SPD will exhibit superplastic ductilities when pulled in tension at elevated temperatures. This review examines recent results that demonstrate the occurrence of exceptional superplastic flow in a series of UFG aluminum and magnesium alloys after ECAP and HPT. The results are analyzed to evaluate the superplastic flow mechanism and to compare with materials processed using different techniques. The critical issue of microstructural inhomogeneity is examined in two-phase UFG materials after SPD processing and the influence of microstructural homogeneity on the superplastic properties is also demonstrated.</P>

Evolution of hardness, microstructure, and strain rate sensitivity in a Zn-22% Al eutectoid alloy processed by high-pressure torsion

Kawasaki, Megumi,Lee, Han-Joo,Choi, In-Chul,Jang, Jae-il,Ahn, Byungmin,Langdon, Terence G IOP Publishing 2014 IOP conference series. Materials science and engin Vol.63 No.-

Computation of annular capacity by Hamiltonian Floer theory of non-contractible periodic trajectories

Kawasaki, Morimichi,Orita, Ryuma American Institute of Mathematical Sciences 2017 Journal of modern dynamics Vol.11 No.-

<P>The first author [9] introduced a relative symplectic capacity C for a symplectic manifold (N, omega(N)) and its subset X which measures the existence of non-contractible periodic trajectories of Hamiltonian isotopies on the product of N with the annulus A(R) = (-R, R) x R/Z. In the present paper, we give an exact computation of the capacity C of the 2n-torus T-2n relative to a Lagrangian submanifold T-n which implies the existence of non-contractible Hamiltonian periodic trajectories on A(R) x T-2n. Moreover, we give a lower bound on the number of such trajectories.</P>

Description of the Superplastic Flow Process by Deformation Mechanism Maps in Ultrafine-Grained Materials

Kawasaki, Megumi,Langdon, Terence G. Trans Tech Publications, Ltd. 2016 Materials science forum Vol.838 No.-

<P>The synthesis of ultrafine-grained (UFG) materials is very attractive because small grains lead to excellent creep properties including superplastic ductility at elevated temperatures. Severe plastic deformation (SPD) is an attractive processing technique for refining microstructures of metallic materials to have ultrafine grain sizes within the submicrometer to even the nanometer level. Among the SPD techniques, most effective processing is conducted through equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) and there are numerous reports demonstrating the improved tensile properties at elevated temperature. This report demonstrates recent results on superplasticity in metals after ECAP and HPT. Moreover, superplastic flow of the UFG materials is evaluated by using flow mechanisms developed earlier for coarse-grained materials and depicted by plotting deformation mechanism maps which provide excellent visual representations of flow properties over a wide range of testing conditions.</P>

Fabrication of nanocomposites through diffusion bonding under high-pressure torsion

Kawasaki, Megumi,Han, Jae-Kyung,Lee, Dong-Hyun,Jang, Jae-il,Langdon, Terence G. Published for the Materials Research Society by th 2018 Journal of materials research Vol.33 No.18

<▼1><B>Abstract</B><P/></▼1><▼2><P>This report summarizes a recent study demonstrating simple and rapid synthesis of a new Al-Mg alloy system and ultimately synthesizing a metal matrix nanocomposite, which was achieved by processing stacked disks of the two dissimilar metals by conventional high-pressure torsion (HPT) processing. The synthesized Al-Mg alloy system exhibits exceptionally high hardness through rapid diffusion bonding and simultaneous nucleation of intermetallic phases with increased numbers of HPT turns through 20, and improved plasticity was demonstrated by increasing strain rate sensitivity in the alloy system after post-deformation annealing. An additional experiment demonstrated that the alternate stacking of high numbers of dissimilar metal disks may produce a faster metal mixture during HPT. Metal combinations of Al-Cu, Al-Fe, and Al-Ti were processed by the same HPT procedure from separate pure metals to examine the feasibility of the processing technique. The microstructural analysis confirmed the capability of HPT for the formation of heterostructures across the disk diameters in these processed alloy systems. The HPT processing demonstrates a considerable potential for the joining and bonding of dissimilar metals at room temperature and the expeditious fabrication of a wide range of new metal systems.</P></▼2>