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991.
Akio Yasuhara Junko Shindo Hiroyasu Ito Tsuguo Mizoguchi Keiichiro Fuwa 《Analytica chimica acta》1985
The library search system described identifies a single component or two components in the unknown pure or mixture mass spectra by comparing them with a large data base of reference spectra. A preliminary search is based on the spectral interpretation and the main search is based on the probability of peak appearance. The performance of this system was tested on 254 pure spectra and 88 mixture spectra. The percentages of successful search by using the NIH/EPA/MSDC data base were 75% for the pure spectra, and 63% for both the first and second components in mixture spectra. The percentages of successful search improved to 94% for the first components of the mixture spectra and 77% for both first and second components of the mixture spectra, when conditions for measurement of reference spectra were the same as those for the unknown spectra. 相似文献
992.
OCCURRENCE OF PHOTOREVERSIBLE ABSORPTION CHANGES IN DISSOCIATED ALLOPHYCOCYANIN AND PHYCOCYANIN 总被引:1,自引:0,他引:1
Abstract— Photochromic response of allophycocyanin (APC) and phycocyanin (PC) was studied. Phycobiliproteins were isolated from the blue-green alga Tolypothrix tennis and supplementary from Anabaena cylindrica. The response was found in both APC and PC when they were dissociated into monomer in the presence of propylene glycol at high concentration. APC in propylene glycol solution showed two photoresponses identical with those of "phycochromes" c and d , respectively. PC showed the photoresponse "phycochrome" a type. After re-association by removal of propylene glycol, photoresponse activities disappeared.
We concluded that (i) some of monomer APC's and PC's became photoreactive when APC and PC were dissociated into monomer thus that (ii) photoresponses of "phycochromes" a, c and d were not attributed to the special pigments independent of APC and PC, but were responsible to special molecules of monomer APC and PC. Spectral patterns of photoresponses were discussed in relation to dissociation-association of protein. 相似文献
We concluded that (i) some of monomer APC's and PC's became photoreactive when APC and PC were dissociated into monomer thus that (ii) photoresponses of "phycochromes" a, c and d were not attributed to the special pigments independent of APC and PC, but were responsible to special molecules of monomer APC and PC. Spectral patterns of photoresponses were discussed in relation to dissociation-association of protein. 相似文献
993.
Yasuda T Yoshimura Y Yabuki H Nakazawa T Ohsawa K Mimaki Y Sashida Y 《Chemical & pharmaceutical bulletin》2003,51(12):1426-1428
During the course of our systematic investigation of the metabolism of flavonoids, the polymethoxyflavone nobiletin, occurring in the fruits of Citrus depressa, was orally administered to rats. The urinary metabolites were separated and identified by three-dimensional HPLC equipped with a photodiode array detector and the structure was determined by spectroscopic methods to be 4'-hydroxy-3',5,6,7,8-pentamethoxyflavone (1). 相似文献
994.
995.
Michiya Fujiki Hong-Zhi Tang Masao Motonaga Keiichi Torimitsu Julian R. Koe Junji Watanabe Takahiro Sato Akio Teramoto 《Silicon Chemistry》2002,1(1):67-72
A new rod-like helical polysilane, poly{(S)-3,7-dimethyloctyl-(2-cyclopentylethyl)silane}, was found to undergo a thermo-driven, helix-helix transition at –33 ° C in isooctane associated with the discontinuous changes in the Si -Si *transition energy and intensity in the transition temperature region. This is the first example of a helix-helix transition polysilane with a cycloalkyl group. A similar rod-like polysilane derivative, poly{(S)-3,7-dimethyloctyl-(1-cyclopentylmethyl)silane}, however, did not undergo any helix-helix transition between –61 and 80 ° C. 相似文献
996.
997.
Zhou SL Matsumoto S Tian HD Yamane H Ojida A Kiyonaka S Hamachi I 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(4):1130-1136
A pH-responsive volume-change function was successfully introduced into a supramolecular hydrogel that contained GalNAc-appended (GalNAc=N-acetylgalactosamine) glutamate ester 1 by the simple mixing of it with an appropriate amount of 2 a or 2 b amphiphilic carboxylic acid. In the 1:1 mixture (1:2), the hydrogel swelled under neutral pH conditions, but shrank to almost half of its original volume under acidic pH conditions. The structure and pH response of the mixed hydrogel were characterized by using X-ray diffraction (XRD), confocal laser scanning microscopy (CLSM), transmission or scanning electron microscopy (TEM, SEM), and Fourier transform IR (FTIR) spectroscopy. Well-developed fibers formed a stable hydrogel by self-assembly, and under acidic conditions the charge of the carboxylic acid terminal (from the carboxylate anion) was neutralized and then these fibers became densely packed. This macroscopic pH response was also applied to the pH-triggered release of bioactive substances. In this mixed supramolecular hydrogel, the hydrogelator 1 provides a stable hydrogel structure and the additive 2 acts as a commander that is sensitive to an environmental pH signal. The present supramolecular copolymerization strategy should be useful for the construction of novel, stimuli-responsive, soft materials. 相似文献
998.
Shin Nishimura Akira Nagai Akio Takahashi Tadashi Narita 《Journal of polymer science. Part A, Polymer chemistry》1993,31(1):135-139
Anionic copolymerizations of 2,3,4,5,6-pentafluorostyrene (PFS) with 1,3-divinylbenzene (m-DVB) and 1,4-divinylbenzene (p-DVB) were performed by using lithium diisopropylamide as an initiator in order to synthesize the fluorine-containing linear polymer with pendant vinyl groups. The products were soluble copolymers possessing both PFS and DVB monomeric units, and the DVB monomeric unit in copolymer had pendant vinyl group. This copolymerization reaction took a much longer time than that of styrene with DVB. The copolymerization parameter of this system was examined from copolymer composition curves. In this system, m-DVB was found to be more reactive than p-DVB. The reactivity of copolymerization was largely influenced by the reactivity of active species. © 1993 John Wiley & Sons, Inc. 相似文献
999.
Highly-sensitive enzymatic immunoassay procedures based on a chemiluminescent reaction are described. Glucose oxidase was used as the labelling enzyme conjugated with anti-α-fetoprotein IgG, insulin or 17-α-hydroxyprogesterone. Free and bound fractions present after the immune reaction were separated by an immobilized antibody or a second antibody. The enzyme activity was measured by the chemiluminescence produced by luminol and hydrogen peroxide, catalyzed by potassium hexacyanoferrate(III) after incubation with glucose. The chemiluminescence was measured in a flow-injection system, with a home-made luminescence detector equipped with a spiral flow cell. The detection limits for each substance were 10?15–10?17 mol. Recoveries of added α-fetoprotein from diluted serum were quantitative. 相似文献
1000.
Murakami R Takata Y Ohta A Takiue T Aratono M 《Journal of colloid and interface science》2004,270(2):262-269
The thermodynamic equations for examining aggregate formation in an oil phase and adsorption at the oil/water interface of a nonionic solute were derived. The total differentials of chemical potentials of species and the oil/water interfacial tension were expressed as functions of temperature, pressure, and the total concentration of solute in the oil phase after explicit consideration of aggregate formation. The partial derivatives of the chemical potentials and the interfacial tension with respect to the independent variables were found to provide the thermodynamic quantities of aggregate formation and adsorption from oil phase to the interface by introducing the concept of an ideally dilute associated solution. These equations were applied to the cyclohexane solution of oleyl alcohol/water system, and the adsorption and aggregate formation was examined. 相似文献