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 $37^{\circ}C$.

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%.

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

Kuwabara, Tomoko,Warashina, Masaki,Taira, Kazunari,Kato, Yoshio,Kawasaki, Hiroaki 생화학분자생물학회 2002 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℃.

PREPARATION OF MONOSIZED SPHERICAL MICRO-PARTICLES AND APPLICATION FOR A TERAHERTZ PHOTONIC CRYSTAL

Kawasaki Akira 한국분말야금학회 2004 한국분말야금학회 학술대회논문집 Vol.2004 No.1

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>

Using high-pressure torsion to process an aluminum-magnesium nanocomposite through diffusion bonding

Kawasaki, Megumi,Ahn, Byungmin,Lee, HanJoo,Zhilyaev, Alexander P.,Langdon, Terence G. Cambridge University Press (Materials Research Soc 2016 Journal of materials research Vol.31 No.1

<▼1><B>Abstract</B><P/></▼1><▼2><P>Disks of commercial Al-1050 and ZK60A alloys were stacked together and then processed by conventional high-pressure torsion (HPT) through 1 and 5 turns at room temperature to investigate the synthesis of an Al-Mg alloy system. Measurements of microhardness and observations of the microstructures and local compositions after processing through 5 turns revealed the formation of an ultrafine multi-layered structure in the central region of the disk but with an intermetallic β-Al3Mg2 phase in the form of nano-layers in the nanostructured Al matrix near the edge of the disk. The activation energy for diffusion bonding of the Al and Mg phases was estimated and it is shown that this value is low and consistent with surface diffusion due to the very high density of vacancy-type defects introduced by HPT processing. The results demonstrate a significant potential for making use of HPT processing in the preparation of new alloy systems.</P></▼2>

Numerical Study on Propagation Characteristics of Tsunami Induced by Tokai, Tonankai and Nankai Massive Earthquakes

Kawasaki, Koji(카와사키 코지),Suzuki, Kazuki(스즈키 카즈키),Lee, Kwang-Ho(이광호),Kim, Do-Sam(김도삼) 한국해안해양공학회 2013 한국해안해양공학회 논문집 Vol.25 No.6

2011년 일본동북지방 대지진 이후, 규모 9.0의 토카이, 토난카이 및 난카이 대규모 지진이 일본 서부의 태평양 해안을 내습할 수 있다는 주장이 제기되고 있다. 본 연구에서는 태평양 해안과 일본의 주요 3대 만인 도쿄만과 이세만 그리고 오사카만에서 규모 9.0의 토카이, 토난카이 및 난카이 대규모 지진에 의해 발생하는 지진해일의 전파 특성을 수치적으로 검토하였다. 본 연구에서 수행된 수치해석결과 M9.0의 지진에 의해 발생하는 태평양 해안에서의 지진해일 높이는 M8.7의 지진에 비해 그 크기가 약 2배에 달하며 지진원으로부터 떨어진 일부 지역에서는 빠른 지진해일의 도달시간을 확인하였다. 또한, 페쇄된 만의 영향에 의해 오랜 시간 동안 만내에서 고수위가 지속됨을 알 수 있었다. After the 2011 Tohoku Earthquake, it has been pointed out that Tokai, Tonankai and Nankai massive earthquakes with a magnitude of 9.0 could strike the Pacific coasts in western Japan. This study aims at investigating numerically propagation characteristics of tsunami generated by a 9.0 magnitude Tokai, Tonankai and Nankai massive earthquakes on the Pacific coasts and three major bays in Japan, Tokyo Bay, Ise Bay and Osaka Bay. It was revealed from the numerical results that the tsunami heights on the Pacific coasts for M9.0 earthquake were about twice as much as those for M8.7 earthquake and the first tsunami arrival time was faster at some areas distant from the tsunami source. Moreover, high water level in the bays was recognized to continue for a long time because of the enclosed bays.

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>

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>

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.