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101.
Sugar-based gemini surfactants with peptide bonds-synthesis, adsorption, micellization, and biodegradability 总被引:1,自引:0,他引:1
Yoshimura T Ishihara K Esumi K 《Langmuir : the ACS journal of surfaces and colloids》2005,21(23):10409-10415
The sugar-based gemini surfactant with peptide bonds, N,N'-bisalkyl-N,N'-bis[2-(lactobionylamide)ethyl]hexanediamide (2C(n)peLac, in which n represents hydrocarbon chain lengths of 12 and 16), was synthesized by reacting adipoyl chloride with the corresponding monomeric surfactant N-alkyl-N'-lactobionylethylenediamine (C(n)peLac), which was obtained by reacting ethylenediamine with alkyl bromide and lactobionic acid. The adsorption and micellization properties of C(n)peLac and 2C(n)peLac were characterized by the measurement of their equilibrium and dynamic surface tension, steady-state fluorescence using pyrene as a probe, dynamic light scattering (DLS), and time-resolved fluorescence quenching (TRFQ), and their biodegradability was also investigated. The critical micelle concentration (cmc) decreases with an increase in the hydrocarbon chains from monomeric to gemini surfactants, whereas it increases with an increase in the chain length from 12 to 16 for both systems. The increases in both the hydrocarbon chain and the chain length of sugar-based surfactants reduce surface activities such as the ability to lower the surface tension, the occupied area per molecule, and the adsorption rate at the air/water interface. The sugar-based surfactants C(n)peLac and 2C(n)peLac exhibit unique aggregation behavior in aqueous solution. The DLS results indicate that the apparent hydrodynamic diameter of C(n)peLac micelles decreases sharply with increasing concentration, whereas that of 2C(n)peLac micelles decreases gradually. From the TRFQ measurement, it was observed that, as concentration increases, the aggregation numbers are almost constant for C(n)peLac, whereas they increase for 2C(n)peLac. These results imply that loosely packed micelles formed by sugar-based surfactants become tightly packed micelles as the concentration increases. Furthermore, it was found that 2C(n)peLac shows lower biodegradability than does C(n)peLac because it contains tertiary amines in the molecule. 相似文献
102.
C. Yonezawa P. P. Ruska H. Matsue M. Magara T. Adachi 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(3):571-575
Determination of ppm levels of B in 21 igneous and sedimentary rocks of the Japanese geochemical reference samples prepared
by the Geological Survey of Japan (GSJ) has been performed by neutron-induced prompt γ-ray analysis (PGA) using cold and thermal
guided neutron beams of the JRR-3M. Owing to the Doppler broadened γ-ray line of B 478 keV, many elements such as Na, Ni,
Cl and so on showed spectral interference in the determination of B. The interference was corrected by computer fitting and
a reference peak method. The analytical results obtained by the present method almost agreed with the GSJ values recommended
in 1994 within the standard deviation of the recommended values. Sodium contents determined by the PGA in the reference rock
samples are also reported. 相似文献
103.
A. Kuno K. Sampei M. Matsuo C. Yonezawa H. Matsue H. Sawahata 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(3):587-590
Neutron induced prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA) have been applied to the
sediments collected from the Yasaka River estuary in Oita Prefecture, Japan. The vertical distribution of 33 elements in the
sediments has been determined and compared with that in more polluted estuarine sediments. While the S content increased with
increasing depth because of a sulphide accumulation under reducing condition, the increase in sulphide-forming elements such
as Ag, Cd, Co and Zn was not observed in the deeper section of the Yasaka River estuarine sediments. 相似文献
104.
Tomokazu Iyoda Takashi Shimura Kenichiro Nakamura Kazuhito Hashimoto Akira Fujishima 《高等学校化学学报》1995,16(Z1):21
The intercalation of various kinds of alcohols into vanadyl-organophosphate powder is investigated mainly by elementary analysis and X-ray diffraction measurement. Not only a series of fatty alcohols but also benzylalcohol derivatives are almost quantitatively intercalated with reasonable relationships between the size of the intercalators and the increasing layer spacing. Another useful preparative method for the host thin film is developed by electrochemical treatment of a conventional V2O5 thin film. 相似文献
105.
Tadashi Kawai Keiichiro Shiga Takehiko Suzuki Tomokazu Iyoda 《Journal of molecular catalysis. A, Chemical》1999,140(3):15-292
Tetravinylsilane and divinylsilanes have been successfully metathesized for the first time over Re2O7/Al2O3 catalyst promoted with tetrabutyltin under mild reaction conditions. All of the products were acyclic oligomers via intermolecular metathesis; the cyclic products via intramolecular metathesis were not formed. 相似文献
106.
107.
108.
Hotta H Kang S Umeyama T Matano Y Yoshida K Isoda S Imahori H 《The journal of physical chemistry. B》2005,109(12):5700-5706
Two kinds of fullerene derivatives have been designed to examine the effect of the fullerene substituents on the structure and photoelectrochemical properties of fullerene clusters electrophoretically deposited on nanostructured SnO(2) electrodes. The cluster sizes increase and the incident photon-to-current efficiencies decrease with introduction of large substituents into C(60). The trend for photocurrent generation efficiency as well as surface morphology on the electrode can be explained by the steric bulkiness around the C(60) molecules. A C(60) molecule with two alkoxy chains is suggested to give a bilayer vesicle structure, irrespective of the hydrophobic nature of both the C(60) and alkoxy chain moieties. Such information will be valuable for the design of photoactive molecules, which are fabricated onto electrode surfaces to exhibit high energy conversion efficiency. 相似文献
109.
Kaya T Nagamine K Matsui N Yasukawa T Shiku H Matsue T 《Chemical communications (Cambridge, England)》2004,(2):248-249
[small beta]-Galactosidase expression in a small number of Escherichia coli cells has been measured in real time with an electrochemical sensor chip. E. coli cells were embedded using collagen gel within a micropore which was microfabricated onto a chip. The activity of the expressed [small beta]-galactosidase was determined using p-aminophenyl [small beta]-d-galactopyranoside (PAPG) as a substrate. 相似文献
110.
Nishida H Miyazaki Y Mukaihira T Saitoh F Fukui M Harada K Itoh M Muraoka A Matsusue T Okamoto A Hosaka Y Matsumoto M Ohnishi S Mochizuki H 《Chemical & pharmaceutical bulletin》2002,50(9):1187-1194
Intravascular clot formation is an important event in a number of cardiovascular diseases. The prevention of blood coagulation has become a major target for new therapeutic agents. Factor Xa (FXa) is a trypsin-like serine protease that plays a key role in the blood coagulation cascade and represents an attractive target for anticoagulant drug development. We have investigated substituents in the central part of a lead compound (3: M55113), and discovered that compound M55551 (34: (R)-4-[(6-Chloro-2-naphthalenyl)sulfonyl]-6-oxo-1-[[1-(4-pyridinyl)-4-piperidinyl]methyl]-2-piperazinecarboxylic acid) is a potent inhibitor of FXa (IC(50)=0.006 microM), with high selectivity for FXa over trypsin and thrombin. The activity of this compound is ten times more powerful than the lead compound. 相似文献