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Summary One considers a system ofN particles on the real line which are of two different types (colours). Their dynamics is given by a stochastic differential equation with constant diffusion part; the drift felt by a particle of either type depends on the empirical measures of type 1 and 2 particles at every instant; further a reflection condition is imposed so that particles of different type are not allowed to cross each other. The article studies the Vlasov-McKean limit of the system asN: propagation of chaos and an evolution equation for the limiting empirical measures is established, from where in particular an equation for the separating front between the two types follos.To the Memory of the late Professor Gishiro Maruýama 相似文献
104.
5alpha-substituted swainsonine analogues were synthesized by Mannich reaction of an in situ generated (-)-swainsonine iminium ion intermediate. 5alpha-substituted swainsonine analogues were epimerized to their 5beta-isomers in protic solvent. [reaction: see text] 相似文献
105.
Synthesis of a Tricyclic Bisguanidine Compound Structurally Related to Saxitoxin and its Identification in Paralytic Shellfish Toxin‐Producing Microorganisms
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Shigeki Tsuchiya Dr. Yuko Cho Prof. Dr. Keiichi Konoki Prof. Dr. Kazuo Nagasawa Prof. Dr. Yasukatsu Oshima Prof. Dr. Mari Yotsu‐Yamashita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7835-7840
We recently reported the chemical synthesis and identification of the genetically predicted biosynthetic intermediates of saxitoxin (STX), including a 2‐aminoimidazole‐bearing monoguanidine compound (Int‐C′2) in two paralytic shellfish toxin (PST)‐producing microorganisms. In this study, we achieved the direct conversion of Int‐C′2 into a tricyclic bisguanidine compound (called Cyclic‐C′), which is structurally related to STX, through oxidative intramolecular guanidine transfer to 2‐aminoimidazole catalyzed by Pd/C under basic conditions in air. By using HPLC‐MS analysis, Cyclic‐C′ was also identified in the PST‐producing microorganisms, suggesting that Cyclic‐C′ is either another biosynthetic intermediate or a shunt product of PSTs. In addition, a weak inhibitory activity of Cyclic‐C′ to the voltage‐gated sodium channels was detected by using a cell‐based assay. 相似文献
106.
Bungo Ochiai Tomomi Nagasawa Yasuhiro Asano Daisuke Nagai Atsushi Sudo Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2007,45(13):2820-2826
Thermal behaviors were monitored by infrared thermographic analysis in the copolymerization of a spiroorthoester and a bifunctional oxetane with thermally latent initiators [benzyl tetrahydrothiophenium hexafluoroantimonate (BTHT) and benzyl 4‐hydroxyphenyl methyl sulfonium hexafluoroantimonate (BPMS)]. The copolymerization with BPMS increased the temperature during the copolymerization more than that with BTHT, whereas the exothermicities were lowered with the increase in the initial feed ratio of the spiroorthocarbonate monomer. The high exothermicity in the copolymerization with BPMS is ascribable to the faster propagation of the oxetane monomer with a high heat of polymerization, and this is supported by model reactions and computational calculation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2820–2826, 2007 相似文献
107.
Akihiro Ohkubo Haruhiko Taguchi Kohji Seio Hiroshi Nagasawa Mitsuo Sekine 《Tetrahedron letters》2007,48(29):5147-5150
DNA chips consisting of DNA oligonucleotide probes immobilized on the surface of solid supports are very powerful tools for rapid analysis of multiple samples. In this Letter we describe a new method for the efficient synthesis of DNA probes without their serious elimination by use of a new hydrophobic 16-hyroxydecanoic linker and a new non-aqueous reagent of MeNH2/THF for the deprotection of the base and phosphate protecting groups on CPG resins. The elimination of DNA probes in this new method could be suppressed more than 20-fold compared with the previous method using a hexaethylene glycol linker and concd NH4OH. Moreover, we carried out SNPs detection by use of our DNA-CPG conjugate to show the utility of our new linker and deprotection conditions. 相似文献
108.
Tomomi Nagasawa Bungo Ochiai Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2007,45(8):1388-1393
Infrared (IR) thermography was employed to monitor temperature changes during the copolymerization of a spiroorthoester monomer with an oxetane monomer initiated with a benzyl sulfonium salt. The temperature changes in the polymerizations decreased with the increase of the initial feed ratios of the spiroorthocarbonate monomer. For instance, the temperature in the copolymerization of the equimolar mixture of both of the monomers increased only ~1 °C, whereas that in the homopolymerization of the oxetane monomer increased more than 20 °C. This result indicates that the copolymerization employing spiroorthocarbonate monomers effectively suppress temperature increase, which are responsible to shrinkage during cooling. The suppression of polymerization shrinkage by spiroorthocarbonate was also confirmed by density measurement of the polymers using a gas pycnometer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1388–1393, 2007. 相似文献
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Tanwistha Ghosh Shinji Nagasawa Neethi Raveendran Vibhu Darshan Akinori Saeki Vijayakumar C. Nair 《化学:亚洲杂志》2019,14(7):963-967
Precise control over the supramolecular organization of organic semiconducting materials guiding to exclusive face‐on or edge‐on orientation is a challenging task. In the present work, we study the preferential packing of thiophene oligomers induced through rational molecular designing and self‐assembly. The acceptor–donor–acceptor‐type oligomers having 2‐(1,1‐dicyano‐methylene)rhodanine as acceptor ( OT1 ) favored a face‐on packing, whereas that of functionalized with N‐octyl rhodanine ( OT2 ) preferred an edge‐on packing as evident from 2D‐grazing incidence angle X‐ray diffraction, tapping‐mode atomic force microscopy (AFM) and Raman spectroscopy analyses. The oligomers exhibited anisotropic conductivity in the self‐assembled state as an outcome of the preferred orientation, revealed by the conducting AFM experiment. 相似文献