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91.
Nakamura H Abe Y Koizumi R Suzuki K Mogi Y Hirayama T Karube I 《Analytica chimica acta》2007,602(1):94-100
A new chemiluminescence biochemical oxygen demand (BODCL) determining method was studied by employing redox reaction between quinone and Baker's yeast. The measurement was carried out by utilizing luminol chemiluminescence (CL) reaction catalyzed by ferricyanide with oxidized quinone of menadione, and Saccharomyces cerevisiae using a batch-type luminometer. In this study, dimethyl sulfoxide was used as a solvent for menadione. After optimization of the measuring conditions, the CL response to hydrogen peroxide in the incubation mixture had a linear response between 0.1 and 100 μM H2O2 (r2 = 0.9999, 8 points, n = 3, average of relative standard deviation; R.S.D.av = 4.22%). Next, a practical relationship between the BODCL response and the glucose glutamic acid concentration was obtained over a range of 11-220 mg O2 L−1 (6 points, n = 3, R.S.D.av 3.71%) with a detection limit of 5.5 mg O2 L−1 when using a reaction mixture and incubating for only 5 min. Subsequently, the characterization of this method was studied. First, the BODCL responses to 16 pure organic substances were examined. Second, the influences of chloride ions, artificial seawater, and heavy metal ions on the BODCL response were investigated. Real sample measurements using river water were performed. Finally, BODCL responses were obtained for at least 8 days when the S. cerevisiae suspension was stored at 4 °C (response reduction, 69.9%; R.S.D. for 5 testing days, 18.7%). BODCL responses after 8 days and 24 days were decreased to 69.9% and 35.8%, respectively, from their original values (R.S.D. for 8 days involving 5 testing days, 18.7%). 相似文献
92.
93.
The high pressure behavior of gallium phosphide, GaP, has been examined using the synchrotron X-ray diffraction technique in a diamond anvil cell up to 27?GPa and 900?K. The transition from a semiconducting to a metallic phase was observed. This transition occurred at 22.2?GPa and room temperature, and a negative dependence of temperature of this transition was found. The transition boundary was determined to be P (GPa)?=?22.6???0.0014?×?T (K). 相似文献
94.
Fast ring opening of mesoionic 1,3-dioxolium-4-olates, generated by Rh(2)(OAc)(4)-catalyzed decomposition of phenyldiazoacetic anhydride derivatives, to acyloxyphenylketenes was demonstrated by trapping the ketenes with several ketenophiles. Reactions of phenyldiazoacetic anhydride derivatives with several ketenophiles such as dihydrofuran, carbodiimides, and imines were carried out. No 1,3-dipolar cycloadducts of the latter with 1,3-dioxolium-4-olates were observed. Instead, only their [2 + 2]-cycloadducts with the acyloxyketenes generated by ring-opening of the initially formed 1,3-dioxolium-4-olates were isolated. In the reaction with cyclopentadiene, 1,3-dipolar cycloadducts with 1,3-dioxolium-4-olates were formed as main products along with the [2 + 2]-ketene adduct. PM3 calculation of heats of formation of 2,5-diphenyl-1,3-dioxolium-4-olate and the corresponding benzoyloxyphenylketene indicates that the ring-opened acyloxyketenes are ca. 9 kcal/mol more stable than the corresponding 1,3-dioxolium-4-olates. 相似文献
95.
Hara T Hirayama F Arima H Yamaguchi Y Uekama K 《Chemical & pharmaceutical bulletin》2006,54(3):344-349
2-(N-Cyanoimino)-5-[(E)-4-styrylbenzylidene]-4-oxothiazolidine (FPFS-410) is a newly synthesized thiazolidine derivative having not only antidiabetic but also lipid-lowering activities. However, this compound has an extremely low aqueous solubility (2.8 (+/-0.33) x 10(-8) M (0.0094+/-0.0011 microg/ml) in 1.0 M phosphate buffer (pH 7.0) at 25 degrees C). In this study, we investigated the effect of various hydrophilic cyclodextrins (CyDs) on the solubility of FPFS-410 to select a CyD suitable for formulations of the compound. Among various CyDs, 2-hydroxypropyl-beta-CyD (HP-beta-CyD) had the highest solubilizing ability to FPFS-410, e.g., the solubility of the compound was increased 200000-fold by the addition of 40 mM HP-beta-CyD, which was attributable to the formation of the 1 : 2 (guest : host) inclusion complexes. The interaction of HP-beta-CyD with FPFS-410 was studied using 1H-nuclear magnetic resonance (NMR) spectroscopies including ROESY spectroscopy and a molecular modeling calculation. These results suggested that HP-beta-CyD forms a 1:2 (guest : host) inclusion complex with FPFS-410 by including both the stilbene and thiazolidine moieties. FPFS-410/HP-beta-CyD solid complexes with various stoichiometries were prepared by the spray drying and cogrinding methods, and confirmed by powder X-ray diffractometry that these complexes are in an amorphous state. The dissolution of FPFS-410 in water was significantly accelerated by the complexation with HP-beta-CyD. In vivo studies revealed that HP-beta-CyD markedly increases the bioavailability of FPFS-410 after oral administration in dogs. The present results suggest that HP-beta-CyD is useful for improvement of the extremely low bioavailability of FPFS-410. 相似文献
96.
The synthesis of a series of hydrosilylboronates via the selective iridium- or nickel-catalyzed monoborylation of dihydrosilane Si–H bonds is described. The synthesized silylboronates, which bear a single Si–H bond, can be used as novel silicon nucleophiles in the presence of transition-metal catalysts or bases. The first 29Si{1H} NMR spectroscopic evidence for the formation of (t-Bu)2HSiLi, generated by the reaction of (t-Bu)2HSi–B(pin) with MeLi, is reported as the first example of a dialkylhydorosilyl lithium species.Monoborylation of a dihydrosilane Si–H bond can be achieved in the presence of iridium- or nickel-based catalysts, yielding novel hydrosilylboronates that bear a hydrogen atom at the silicon center. 相似文献
97.
Tsutomu Asano Shota Sano Toshihiko Okabe Takumi Sano Chie Sawatari 《Journal of Macromolecular Science: Physics》2018,57(5):317-332
Using a modified method developed from Vonk's method, detailed values of crystallinity and crystal disorder were obtained by wide angle X-ray diffraction (WAXD). In Vonk's method, the crystallinity (w) is determined by extrapolation of the WAXD experimental curve back to zero scattering angle, while the distortion factor (k) is determined by the inclination of the experimental curve at zero scattering angle. In our new method, both w and k are determined at the same time by using the least squares method. In order to show the efficiency of our method, the new fitting procedure was applied to the experimental values of polyethylene and polyethylene terephthalate as measured by Vonk, and the values of w and k determined by our new method were compared with those found by Vonk's method. The new fitting method has the advantage that it uses the whole experimental curve. Moreover, our modified Vonk's method enables us to discuss crystal distortions as arising from first-kind (thermal) disorder and second-kind (paracrystalline) disorder. 相似文献
98.
Takumi Inadomi Shogo Ikeda Yasushi Okumura Hirotsugu Kikuchi Nobuyoshi Miyamoto 《Macromolecular rapid communications》2014,35(20):1741-1746
Poly‐(N‐isopropylacrylamide) (PNIPA) hydrogel films doped with uniaxially aligned liquid crystalline (LC) nanosheets adsorbed with a dye are synthesized and its anomalous photothermal deformation is demonstrated. The alignment of the nanosheet LC at the cm‐scale is easily achieved by the application of an in‐plane or out‐of‐plane AC electric field during photo‐polymerization. A photoresponsive pattern is printable onto the gel with μm‐scale resolution by adsorption of the dye through a pattern‐holed silicone rubber. When the gel is irradiated with light, only the colored part is photothermally deformed. Interestingly, the photo‐irradiated gel shows temporal expansion along one direction followed by anisotropic shrinkage, which is an anomalous behavior for a conventional PNIPA gel.
99.
SK Podiyanachari R Fröhlich CG Daniliuc JL Petersen G Kehr G Erker N Suzuki S Yuasa K Hagimori S Inoue T Asada T Takemoto Y Masuyama 《Dalton transactions (Cambridge, England : 2003)》2012,41(35):10811-10816
The reaction of η(2)-iminozirconocene chloride complexes with trimethylsilylethynyl lithium leads to rapid C-C coupling at room temperature to yield the corresponding five-membered aza-zirconacycloallenoids. Such compounds were also obtained by trapping of in situ generated zirconocene with alkynyl imines. 相似文献
100.
Yoshimura T Kusano T Iwase H Shibayama M Ogawa T Kurata H 《Langmuir : the ACS journal of surfaces and colloids》2012,28(25):9322-9331
Novel star-shaped trimeric surfactants consisting of three quaternary ammonium surfactants linked to a tris(2-aminoethyl)amine core were synthesized. Each ammonium had two methyls and a straight alkyl chain of 8, 10, 12, or 14 carbons. The adsorption and aggregation properties of these tris(N-alkyl-N,N-dimethyl-2-ammoniumethyl)amine bromides (3C(n)trisQ, in which n represents alkyl chain carbon number) were characterized by equilibrium and dynamic surface tension, rheology, small-angle neutron scattering (SANS), and cryogenic transmission electron microscopy (cryo-TEM) techniques. 3C(n)trisQ showed critical micelle concentrations (CMC) 1 order of magnitude lower than that of the corresponding gemini surfactants with an ethylene spacer and the corresponding monomeric surfactants. The logarithm of the CMC decreased linearly with increasing hydrocarbon chain length for 3C(n)trisQ. The slope of the line, which is well-known as Klevens equation, was larger than those of the monomeric and gemini surfactants; however, considering the total carbon number in the chains, the slope was shallower than the monomeric and was close to the gemini. Through the results such as surface tensions at the CMC (32-34 mN m(-1)) and the parameters of standard free energy, CMC/C(20) and pC(20), it was found that 3C(n)trisQ could adsorb densely at the air/water interface despite the strong electrostatic repulsion between multiple quaternary ammonium headgroups. Moreover, dynamic surface tension measurements showed that the kinetics of adsorption for 3C(n)trisQ to the air/water interface was slow because of their bulky structures. Furthermore, the results of rheology, SANS, and cryo-TEM determined that 3C(n)trisQ with n = 10 and 12 formed ellipsoidal micelles at low concentrations in solution and the structures transformed to threadlike micelles with very few branches for n = 12 as the concentration increased, but for n = 14 threadlike micelles formed at relatively low concentrations. 相似文献