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1.
A self-propelled object coupled with an enzyme reaction between urease and urea was investigated at the air/aqueous interface. A plastic object that was fixed to a urease-immobilized filter paper was used as a self-propelled object, termed a urease motor, placed on an aqueous urea solution. The driving force of the urease motor is the difference in the surface tension around the object. Oscillatory motion or no motion was triggered depending on the initial pH of the urea solution. Both the frequency and maximum speed of the oscillatory motion varied depending on the initial pH of the water phase. The mechanisms underlying the oscillatory motion and no motion were discussed in relation to the bell-shaped enzyme activity of urease in the enzyme reaction and the surface tension around the urease motor. 相似文献
2.
Shunsuke Takagi Kei-ichi Watanabe 《Transactions of the American Mathematical Society》2004,356(10):3951-3961
Demailly, Ein and Lazarsfeld proved the subadditivity theorem for multiplier ideals on nonsingular varieties, which states the multiplier ideal of the product of ideals is contained in the product of the individual multiplier ideals. We prove that, in the two-dimensional case, the subadditivity theorem holds on log terminal singularities. However, in the higher dimensional case, we have several counterexamples. We consider the subadditivity theorem for monomial ideals on toric rings and construct a counterexample on a three-dimensional toric ring.
3.
Shunsuke Inenaga Ayumi Shinohara Masayuki Takeda Setsuo Arikawa 《Journal of Discrete Algorithms》2004,2(1):33
Suffix trees are a well-known and widely-studied data structure highly useful for string matching. The suffix tree of a string w can be constructed in O(n) time and space, where n denotes the length of w. Larsson achieved an efficient algorithm to maintain suffix trees for a sliding window. It contributes to prediction by partial matching (PPM) style statistical data compression scheme. Compact directed acyclic word graphs (CDAWGs) are a more space-economical data structure for indexing strings. In this paper we propose a linear-time algorithm to maintain CDAWGs for a sliding window. 相似文献
4.
Precise characterization of noncollinear optical parametric amplifier idler pulses that have bandwidths of more than an octave with a center wavelength at 990 nm was demonstrated. The method employed was cross-correlation frequency-resolved optical gating with broadband sum-frequency mixing to take advantage of the idler's angular dispersion. Compression to near the transform limit was achieved to produce quasi-monocyclic near-infrared pulses by use of a deformable membrane mirror. 相似文献
5.
6.
Yan Yin Otoo Yamada Shunsuke Hayashi Kazuhiro Tanaka Hidetoshi Kita Ken‐Ichi Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2006,44(12):3751-3762
A series of branched/crosslinked sulfonated polyimide (B/C‐SPI) membranes were prepared and evaluated as proton‐conducting ionomers based on the new concept of in situ crosslinking from sulfonated polyimide (SPI) oligomers and triamine monomers. Chemical branching and crosslinking in SPI oligomers with 1,3,5‐tris(4‐aminophenoxy)benzene as a crosslinker gave the polymer membranes very good water stability and mechanical properties under an accelerated aging treatment in water at 130 °C, despite their high ion‐exchange capacity (2.2–2.6 mequiv g?1). The resulting polymer electrolytes displayed high proton conductivities of 0.2–0.3 S cm?1 at 120 °C in water and reasonably high conductivities of 0.02–0.03 S cm?1 at 50% relative humidity. In a single H2/O2 fuel‐cell system at 90 °C, they exhibited high fuel‐cell performances comparable to those of Nafion 112. The B/C‐SPI membranes also displayed good performances in a direct methanol fuel cell with methanol concentrations as high as 50 wt % that were superior to those of Nafion 112. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3751–3762, 2006 相似文献
7.
Kakiuchi F Tsuchiya K Matsumoto M Mizushima E Chatani N 《Journal of the American Chemical Society》2004,126(40):12792-12793
Ruthenium-catalyzed silylation of sp3 C-H bonds at a benzylic position with hydrosilanes gave benzylsilanes. For this silylation reaction, Ru3(CO)12 complex showed high catalytic activity. This silylation proceeded at the methyl C-H bond selectively. For this silylation reaction, pyridyl and pyrazolyl groups, and the imino group in hydrazones, can function as a directing group. Several hydrosilanes involving triethyl-, dimethylphenyl-, tert-butyldimethyl-, and triphenylsilanes can be used as a silylating reagent. Coordination of an sp2 nitrogen atom to the ruthenium complex is important for achieving this silylation reaction. 相似文献
8.
Chatani N Amako K Tobisu M Asaumi T Fukumoto Y Murai S 《The Journal of organic chemistry》2003,68(4):1591-1593
The reaction of benzofuran-2,3-dione derivatives 1 with CO and alkenes (or alkynes) results in a carbonylative [2+2+1] cycloaddition in which the ester-carbonyl group is incorporated into a two-atom assembling unit to give spirolactone derivatives 2. This reaction provides the first example of an ester-carbonyl group participating in a carbonylative cycloaddition reaction. 相似文献
9.
Etsuo Watanabe Shunsuke Tokimatsu Kenzo Toyama Isao Karube Hideaki Matsuoka Shuichi Suzuki 《Analytica chimica acta》1984
A multielectrode enzyme sensor for the simultaneous determination of adenosine-5′-phosphate (AMP), inosine-5′-phosphate (IMP), inosine (HXR) and hypoxanthine (HX)in fish meat was developed by assembling four enzyme sensors for AMP, IMP, HXR and HX in a flow cell. These compounds were determined from oxygen consumption according to the following reactions: AMP IMP HXR HX Uric acid where AD is AMP deaminase, NT is 5′-nucleotidase, NP is nucleoside phosphorylase and XO is xanthine oxidase. Enzymes were covalently bound to a membrane prepared from cellulose triacetate, 1,8-diamino-4-aminomethyloctane and glutaraldehyde. Sensors for HX, HXR, IMP and AMP were prepared by attaching membranes of XO, XONP, XO NPNT, and of XONPNT and AD, respectively, to four oxygen electrodes. Samples extracted from sea bass, bream, flounder, abalone and arkshell were analyzed within 5 min, from the simultaneous response curves of the four electrodes. Results obtained by the multisensor system were in good agreement with those determined by each single electrode. 相似文献
10.
The reaction of alpha,beta-unsaturated imines with CO and alkenes in the presence of Ru(3)(CO)(12) as a catalyst results in a three-component coupling reaction that gives alpha,alpha-disubstituted beta,gamma-unsaturated gamma-butyrolactams. The reaction proceeds via a two-step sequence involving the initial formation of ketone derivatives by catalytic carbonylation at the beta-olefinic C-H bonds of alpha,beta-unsaturated imines, followed by the (uncatalyzed) intramolecular nucleophilic attack of the imine nitrogen on the ketonic carbon to generate a tetrahedral intermediate, which then undergoes a 1,2-ethyl migration. The reaction of a cyclic unsaturated imine, derived from the reaction of (1R)-(-)-myrtenal with tert-butylamine, gives a beta-aminocyclopentene derivative, which is formed by an aldol-type condensation of the initially formed ketone, indicating the initial formation of ethyl ketone. 相似文献