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21.
Yamada K Harada Y Miyamoto T Isobe R Higuchi R 《Chemical & pharmaceutical bulletin》2000,48(1):157-159
A new ganglioside molecular species, HPG-7 (1) was obtained from the polar fraction of the chloroform/methanol extract of the sea cucumber, Holothuria pervicax. On the basis of chemical and spectroscopic evidence, the structure of 1 was determined, and the major component was 1-O-[alpha-L-fucopyranosyl-(1-->4)-(N-acetyl-alpha-D-neuraminosyl) - (2-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->4)-(N-acetyl -alpha-D- neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-(2S,3S,4R)-2-[(2R)-2- hydroxytetracosanoylamino]-14-methyl-hexadecane-1,3,4-triol. This is the first report on the isolation and structure elucidation of trisialo-ganglioside from sea cucumber. 1 showed neuritogenic activity toward the rat pheochromocytoma cell line, PC-12 cell. 相似文献
22.
23.
Atsunori Matsuda Tatsuo Matoda Yoshinori Kotani Toshihiro Kogure Masahiro Tatsumisago Tsutomu Minami 《Journal of Sol-Gel Science and Technology》2003,26(1-3):517-521
Anatase nanocrystals were precipitated mainly at the surface of the silica-titania gel films with hot water treatment, whereas the addition of poly(ethylene glycol) (PEG) in the films led to the dispersion of anatase nanocrystals in the whole of the films after the treatment. Both films with and without PEG showed high photocatalytic activities for acetaldehyde, NO
x
and stearic acid in the gas-solid system, and for methylene blue and potassium iodide in the liquid-solid system. The addition of PEG improved the photocatalytic activities of the resultant films due to the smaller anatase crystallites and the porous film structure. The residual silica under-layer of the superficially anatase-precipitated films is expected to act as a protective one for an organic polymer substrate against the photocatalytic degradation. 相似文献
24.
Y. Miyamoto Y. Saito M. Magara S. Usuda 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(3):553-557
To clarify the magnitude of wash-out effect of rain on the elemental composition of airborne dust and the possible origin of the dust, the dust samples were collected with a high-volume air sampler at the JAERI-Tokai. The dust suspended in rain was also collected from rain by filtration. Up to 20 elements in both types of the dust were determined by instrumental neutron activation analysis. It was found that the elements determined could be classified into 3 groups from the elemental composition and the elemental correlation in both types of the dust samples. 相似文献
25.
Masahiro?Okada Takumi?Matoba Masayoshi?OkuboEmail author 《Colloid and polymer science》2003,282(2):193-197
The influence of nonionic emulsifier, included inside styrene-methacrylic acid copolymer [P(S-MAA)] particles during emulsion copolymerization, on the formation of multihollow structure inside the particles via the alkali/cooling method (proposed by the authors) was examined in comparison to emulsifier-free particles. It was clarified that the nonionic emulsifier included inside the P(S-MAA) particles eased the formation of multihollow structure.Part CCL of the series studies on suspension and emulsion 相似文献
26.
Atsunori Matsuda Tatsuo Matoda Toshihiro Kogure Kiyoharu Tadanaga Tsutomu Minami Masahiro Tatsumisago 《Journal of Sol-Gel Science and Technology》2004,31(1-3):229-233
Titania nanosheet-precipitated coatings have been prepared by treating SiO2-TiO2 gel films on glass substrates with hot water at 90°C under vibration. Longitudinal vibrations at about 6 Hz during the treatment enhanced the formation of titania nanosheet. The titania nanosheet consisted of several layers with a spacing of about 0.6 nm and was identified as hydrated titania with a lepidocrocite-type structure. The morphology of the titania nanosheet-precipitated coatings is probably achieved by lowering of the concentration of hydrolyzed titania species at the surface due to rapid water flow driven by the vibrations. The coatings were transparent in the visible range and showed high photocatalytic activity and antifogging property. 相似文献
27.
Ken-Ichi Ito Masamichi Nishimura Minoru Sashio Masahiro Tsunooka 《Journal of polymer science. Part A, Polymer chemistry》1994,32(11):2177-2185
It was found that amines were formed efficiently by the photolysis of O-acyloximes followed by hydrolysis in polystyrene films and the relationship between structures of O-acyloximes and yields of amines were investigated. O-phenylacetyl acetophenone oxime (PaApO), O-pivaloyl acetophenone oxime (PApO), and O-benzoyl acetophenone oxime (BApO) as monofunctional O-acyloximes and O,O′-succinyl diacetophenone oxime (SDApO) and O,O′-glutaryl diacetophenone oxime (GDApO) as bifunctional O-acyloximes were examined. The yields of amines for PaApO and SDApO under N2 were ca. 70%, which was the highest among O-acyloximes examined in this experiment. On the other hand, the yields for PApO, BApO, and GDApO were less than 15% and it was verified that the hydrogen abstraction by imino radicals via 6-membered cyclic intermediates resulted in the lowering of yields. Although the effect of oxygen under photolysis on the yields of amine for PaApO was negligible under 50% conversion of PaApO, the yield decreased with further increase in the conversion and was 50% at 90% conversion. © 1994 John Wiley & Sons, Inc. 相似文献
28.
Ichinose H Michizoe J Maruyama T Kamiya N Goto M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(13):5564-5568
Enzyme-based electron-transfer reactions involved in the cytochrome P450 monooxygenase system were investigated in nanostructural reverse micelles. A bacterial flavoprotein, putidaredoxin reductase (PdR), was activated and shown to be capable of catalyzing the electron transport from NADH to electron-carrier proteins such as cytochrome b5 (tCyt-b5) and putidaredoxin (Pdx) in reverse micelles. Ferric tCyt-b5 in reverse micelles was effectively converted to its ferrous form by the exogenous addition of separately prepared reverse micellar solution harboring PdR and NADH. The fact that direct interactions of macromolecular proteins should be possible in the reverse micellar system encouraged us to functionalize a multicomponent monooxygenase system composed of the bacterial cytochrome P450cam (P450cam), putidaredoxin (Pdx), and PdR in reverse micelles. The successful camphor hydroxylation reaction catalyzed by P450cam was significantly dependent on the coexistence of Pdx, PdR, and NADH but not H2O2, suggesting that the oxygen-transfer reactions proceeded via a "monooxygenation" mechanism. This is the first report of a multicomponent cytochrome P450 system exhibiting enzymatic activity in organic media. 相似文献
29.
T. Miyamoto Y. Sato T. Shibata H. Inagaki M. Tanahashi 《Journal of polymer science. Part A, Polymer chemistry》1984,22(10):2363-2370
13C-NMR spectra of ring carbons and O-acetyl carbonyl carbons of cellulose acetate (CA) in dimethyl sulfoxide-d6 were analyzed. The CA samples with the degree of substitution (DS) ranging from 0.84 and 1.91 were prepared by homogeneous acetylation of cellulose with acetic anhydride in a 10% LiCl/dimethyl acetamide solvent. It was found that the use of these low DS samples permitted easier assignments not only of the ring carbon but also of the O-acetyl carbonyl carbon signals. The assignments were confirmed by comparing with the 1H-NMR spectra of the samples obtained by complete acetylation of the corresponding CA samples with acetyl-d3 chloride. Two methods for determining the distribution of O-acetyl groups of CA, i.e., the relative DS at the three different types of hydroxyl groups, were developed. One is based on the measurements of the relative intensities of the signals for the ring carbons and the other is based on the measurements of the relative intensities of the signals for the O-acetyl carbonyl carbons. 相似文献
30.
Ooi Y Hobara D Yamamoto M Kakiuchi T 《Langmuir : the ACS journal of surfaces and colloids》2005,21(24):11185-11189
In formation of binary self-assembled monolayers (SAMs) composed of 2-aminoethanethiol (AET) and 2-mercaptoethane sulfonic acid (MES) by adsorption from an ethanol solution on Au(111), the adsorption shows nearly ideal nonideality in that the surface ratio of MES to AET in the SAM is unity and does not depend on the mixing ratio of MES to AET in the bathing ethanol solution used for preparing SAMs, chi(soln)MES, over the wide range of chi(soln)MES between 0.01 and 0.95. X-ray photoelectron spectroscopy confirms that at least 80% of AET molecules adsorbed are protonated in this range of chi(soln)MES, indicating that the electrostatic interaction between positively charged AET and negatively charged MES is responsible to the observed nonideality. Correspondingly, there appears only one cathodic peak in a linear-sweep voltammogram of the reductive desorption of the SAM, having a narrow full width at half-maximum of about 20 mV. This suggests the presence of strong lateral attractive interaction between the adsorbed thiolates. 相似文献