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951.
952.
ABSTRACT Periodate oxidation of glucans afforded a dialdehyde structure, which was highly reactive with various compounds containing amino groups. A covalent Schiff base linkage was readily formed at the alkaline pH of 8-9 and cyclodextrin dialdehyde gave both positively and negatively charged derivatives upon incubation with hexamethylenediamine and ?-aminocaproic acid, respectively. Binding of the amino group containing a fluorescent probe of ethylenediaminonaphthalene yielded fluorescent glycogen, which was hydrolyzed with Taka-amylase A. By gel filtration with a Bio-Gel P-2 column, hydrolyzed oligosaccharides containing a fluorescent probe were strongly retained to the column. Dextran dialdehyde was useful in producing a covalent linkage with trypsin under very mild conditions, and the enzyme-dextran complex formed was recovered in a high-molecular weight and active form. Thus, various glucan dialdehydes may serve as useful cross-linking reagents for enzymes. 相似文献
953.
Teruaki Toyota Tadashi Hanafusa Takashi Oda Iwane Koumura Takanori Sasaki Eiji Matsuura Hiromi Kumon Tsuneo Yano Toshiro Ono 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):295-300
Ion exchange is a simple and efficient method for separating no-carrier-added 64Cu from an irradiated Ni target. We developed a semi-automated two-round 64Cu separation system equipped with a strong-base anion exchange resin column. We first verified the efficiency of the system using a non-radioactive substitute consisting of 25 mg of Ni and 127 ng of Cu, and confirmed that Cu was completely eluted at the second round of the separation step. After the bombardment, separation of 64Cu from the Ni target was achieved with high radiochemical purity. 64Cu produced and separated in this study had an extremely low level of Ni impurity. It could be used for labeling monoclonal antibodies for antibody positron emission tomography imaging and synthesizing radiopharmaceuticals. 相似文献
954.
(E)-1-Alkenylsilanes with an amino or an alkoxy group on silicon can be conveniently synthesized by regioselective coupling of a potassium reagent derived from an allyl(amino)silane with alkyl halides. 相似文献
955.
Shigeru Arimoto Mark Spivakovsky Eiji Yoshida Keith F. Taylor Paul G. Mezey 《Journal of mathematical chemistry》2011,49(8):1700-1712
The present article is a direct continuation of part IV of this series. The Local Analyticity Proposition (LAP1), which admits
a proof via resolution of singularities is a major key to proving the Fukui conjecture via resolution of singularities and
related methods. By LAP1, the essential part of the mechanism of the “asymptotic linearity phenomena” is extracted and is
elucidated by using tools from the theory of algebraic and analytic curves. Here in the present article, we complete the proof
of the LAP1 by using fundamental tools developed in parts III and IV of this series, thus completing the proof of the Fukui
conjecture via resolution of singularities and related methods. This series of articles I-V establishes, for the first time,
a new linkage between (i) the mathematical field of resolution of singularities and (ii) the chemical field of additivity
problems tackled and solved in a unifying manner via the repeat space theory (RST), which is the central theory in the First
and Second Generation Fukui Project. A new development called the Matrix Art Program in the Second Generation Fukui Project
has also been expounded with a graphical representation of energy band curves of a carbon nanotube. 相似文献
956.
Direct triarylation and sequential triarylation reactions of simple azoles catalyzed by [Pd(phen)(2)]PF(6) are described. Simple azoles, such as N-methylimidazole, thiazole, and oxazole, were observed to undergo triaryaltion reactions even at their C4 positions when treated with aryl iodides in the presence of [Pd(phen)(2)]PF(6) as a catalyst and a stoichiometric amount of Cs(2)CO(3) in DMA at 150 °C. Using excess amounts of azoles, selective C5 monoarylation was achieved by using the same catalytic system. Subsequent efforts demonstrated that C5 arylated azoles undergo exclusive C2 arylation using [Pd(phen)(2)]PF(6) as the catalyst with galvinoxyl as an additive. Finally, unprecedented C4 arylation reactions of 2,5-diaryl-azoles occur by using the new catalytic system to give the corresponding triarylated products in good to excellent yields. The results of mechanistic studies suggest that the C2 arylation process takes place by way of an electrophilic aromatic substitution (S(E)Ar) palladation pathway, while arylation reactions at the C4 position occur via a S(E)Ar palladation and/or radical mechanism. Finally, a concise, three-step synthesis of the Tie-2 Tyrosine Kinase Inhibitor has been executed starting with commercially available N-methylimidazole by a route that employs the new sequential arylation process. 相似文献
957.
958.
959.
A simple multilevel halftoning method, which is based on the conventional error diffusion method and realizes halftoning excelled in the distribution of dots, is proposed. The proposed method consists of three steps, e.g., the image decomposition, the generation of binary halftone images by the error diffusion, and the synthesis of a multilevel halftone image, and each step does not require a complicated algorithm. The effectiveness of the proposed method is indicated by applying it to three- and four-level halftoning of gray-tone and natural images. 相似文献
960.
In multimedia content, colors play important roles in conveying visual information. However, color information cannot always
be perceived uniformly by all people. People with a color vision deficiency, such as dichromacy, cannot recognize and distinguish
certain color combinations. In this paper, an effective lightness modification method, which enables barrier-free color vision
for people with dichromacy, especially protanopia or deuteranopia, while preserving the color information in the original
image for people with standard color vision, is proposed. In the proposed method, an optimization problem concerning lightness
components is first defined by considering color differences in an input image. Then a perceptible and comprehensible color
image for both protanopes and viewers with no color vision deficiency or both deuteranopes and viewers with no color vision
deficiency is obtained by solving the optimization problem. Through experiments, the effectiveness of the proposed method
is illustrated. 相似文献