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81.
Júlia La
n Jan Pikryl Norio Teshima Hiroya Murakami Yukihiro Esaka Frantiek Foret Petr Kub 《Electrophoresis》2019,40(18-19):2390-2397
In this article, optimization of BGE for simultaneous separation of inorganic ions, organic acids, and glutathione using dual C4D‐LIF detection in capillary electrophoresis is presented. The optimized BGE consisted of 30 mM 2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl]ethanesulfonic acid, 15 mM 2‐amino‐2‐hydroxymethyl‐propane‐1,3‐diol, and 2 mM 18‐crown‐6 at pH 7.2 and allowed simultaneous separation of ten inorganic anions and cations, three organic acids and glutathione in 20 min. The samples were injected hydrodynamically from both capillary ends using the double‐opposite end injection principle. Sensitive detection of anions, cations, and organic acids with micromolar LODs using C4D and simultaneously glutathione with nanomolar LODs using LIF was achieved in a single run. The developed BGE may be useful in analyses of biological samples containing analytes with differing concentrations of several orders of magnitude that is not possible with single detection mode. 相似文献
82.
Koichi Kajihara Taisuke Miura Hayato Kamioka Akira Aiba Motoko Uramoto Yukihiro Morimoto Masahiro Hirano Linards Skuja Hideo Hosono 《Journal of Non》2008,354(2-9):224-232
This article briefly summarizes the diffusion and reactions of interstitial oxygen species in amorphous SiO2 (a-SiO2). The most common form of interstitial oxygen species is oxygen molecule (O2), which is sensitively detectable via its characteristic infrared photoluminescence (PL) at 1272 nm. The PL observation of interstitial O2 provides key data to verify various processes related to interstitial oxygen species: the dominant role of interstitial O2 in long-range oxygen transport in a-SiO2; formation of the Frenkel defect pair (Si–Si bond and interstitial oxygen atom, O0) by dense electronic excitation; efficient photolysis of interstitial O2 into O0 with F2 laser light (λ = 157 nm, hν = 7.9 eV); and creation of interstitial ozone molecule via reaction of interstitial O2 with photogenerated O0. The efficient formation of interstitial O0 by F2 laser photolysis makes it possible to investigate the mobility, optical absorption, and chemical reactions of interstitial O0. The observed properties of O0 are consistent with the model that O0 takes the configuration of Si–O–O–Si bond. Interstitial O2 and O0 react with dangling bonds, oxygen vacancies, and chloride groups in a-SiO2. Reactions of interstitial O2 and O0 with mobile interstitial hydrogen species produce interstitial water molecules and hydroperoxy radicals. Interstitial hydroxyl radicals are formed by F2 laser photolysis of interstitial water molecules. 相似文献
83.
84.
Mariko Kitajima Tomomi Yanagisawa Mari Tsukahara Yasuka Yamaguchi Noriyuki Kogure Ruri Kikura-Hanajiri Yukihiro Goda Osamu Iida Yasushi Sugimura Nobuo Kawahara Hiromitsu Takayama 《Tetrahedron》2018,74(4):441-452
Three new biphenyl ether quinolizidine lactone alkaloids (1–3) and 13 new biphenyl quinolizidine lactone alkaloids (4–16) were isolated from Heimia salicifolia (Lythraceae) together with seven known alkaloids. Their structures were determined by spectroscopic analyses and chemical conversions. 相似文献
85.
Yan C Zhang Y Hu Y Ozaki Y Shen D Gan Z Yan S Takahashi I 《The journal of physical chemistry. B》2008,112(11):3311-3314
The structure evolution of poly(butylene adipate) (PBA) during isothermal melt crystallization and phase transition processes is investigated by Fourier transform infrared spectroscopy (FTIR). Detailed IR spectra analysis and band assignment are performed to disclose the bands sensitive to the alpha-form crystalline order of PBA. It is revealed from the in situ IR study that the functionalities within PBA chains alter simultaneously during the melt crystallization process. From the analysis of the spectral changes, it is found that band shifts take place during the phase transition process of PBA from its metastable beta-form crystal to the stable alpha-form. Notable band shifts in the 1300-1100 cm(-1) region indicate that the twist of polymer chains in the alpha-form is located in the C-O-C and C-O linkages. Moreover, the results elucidated that the different segments of molecular chains tune up their conformations synchronously during the beta to alpha crystal transition process of PBA. It is suggested that the betaalpha phase transition process proceeds randomly throughout the solid at a constant rate. 相似文献
86.
Motoyama Y Abe M Kamo K Kosako Y Nagashima H 《Chemical communications (Cambridge, England)》2008,(42):5321-5323
Novel ruthenium-encapsulating polysiloxane gels are prepared by treatment of polymethylhydrosiloxane with diols in the presence of (mu(3),eta(2),eta(3),eta(5)-acenaphthylene)Ru(3)(CO)(7), and act as reusable catalysts in the isomerization of alkenes without leakage of the catalyst species. 相似文献
87.
Larriba C Yoshida Y Fernández de la Mora J 《The journal of physical chemistry. B》2008,112(39):12401-12407
An effort to systematize published and new data on the surface tension gamma of ionic liquids (ILs) is based on the hypothesis that the dimensionless surface tension parameter gamma V v (2/3)/ kT is a function of the void fraction x v = V v/ V m. The void volume V v is defined as the difference between the liquid volume V m occupied by an ion pair (known from cationic and anionic masses and liquid density measurements) and the sum V (+) + V (-) of the cationic and anionic volumes (known from crystal structures), while kT is the thermal energy. Our hypothesis that gamma V m (2/3)/ kT = G( x v) is initially based on cavity theory. It is then refined based on periodic lattice modeling, which reveals that the number N of voids per unit cell (hence the dimensionless surface tension) must depend on x v. Testing our hypothesis against data for the five ILs for which surface tension and density data are available over a wide range of temperatures collapses all of these data almost on a single curve G( x v), provided that slight (4%) self-consistent modifications are introduced on published crystallographic data for V (+) and V (-). An attempt to correlate the surface tension vs temperature data available for inorganic molten salts is similarly successful, but at the expense of larger shifts on the published ionic radii (8.8% for K; 3.3% for I). The collapsed G( x v) curves for ILs and inorganic salts do not overlap anywhere on x v space, and appear to be different from each other. The existence of a relation between gamma and x v is rationalized with a simple capillary model minimizing the energy. Our success in correlating surface tension to void fraction may apply also to other liquid properties. 相似文献
88.
To establish an immunoassay for baicalin (BA), a hybridoma cell line (9D6) secreting a monoclonal antibody (MAb) against BA was prepared by cell fusion with splenocytes derived from a mouse immunized with BA-bovine serum albumin (BSA) conjugate and a myeloma cell line, SP2/0-Ag14. MAb 9D6 shows specific reactivity against BA and its aglycone, baicalein, but not against other natural products. We developed an enzyme-linked immunosorbent assay (ELISA) using MAb 9D6 in a competitive manner, ranging from 200 ng/mL to 2 μg/mL. After validating the developed ELISA on the basis of intra- and inter-assays and a recovery experiment, it was found that the ELISA was not only simple, but also sufficiently reliable and accurate for quality control of Scutellariae Radix. It allowed determination of BA in complex and mixed materials, such as Kampo medicines. 相似文献
89.
Jin J Sugiyama Y Mitsui K Arakawa H Ichinose I 《Chemical communications (Cambridge, England)》2008,(8):954-956
Nanomechanical properties of free-standing reversed surfactant bilayers, dried foam films (DFFs), were examined via AFM by fitting local force-indentation curves with a Hertzian model. The Young's moduli of four kinds of bilayers were in a range of 10-30 MPa. 相似文献
90.
Podstawka E Ozaki Y Proniewicz LM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(19):10807-10816
Raman (RS) and surface-enhanced Raman scattering spectra (SERS) were measured for various length carboxyl terminal fragments (X-14 of amino acid sequence) of bombesin ( BN): BN13-14, BN12-14, BN11-14, BN10-14, BN9-14, and BN8-14 in silver colloidal solutions. Density functional theory (DFT) calculations of Raman wavenumbers and intensities with extended basis sets (B3LYP/6-31++G**) were performed with the aim of providing the definitive band allocations to the normal coordinates. The proposed band assignment is consistent with the assignment for similar compounds reported in the literature. The nonadsorbed and adsorbed molecular structures were deducted by detailed spectral analysis of the RS and SERS spectra, respectively. This analysis also allowed us to propose the particular surface geometry and orientation of these peptides on silver surface, and their specific interaction with the surface. For example, a SERS spectrum of BN8-14 indicates that the interaction of a thioether atom and Trp8 with the silver surface is favorable and may dictate the orientation and conformation of adsorbed peptide. One of the most prominent and common features in all of the fragments' SERS spectra is a approximately 692 cm (-1) band due to nu(C-S) accompanied by two or three bands of different C-S conformers for all, except BN8-14, which suggests that all of the above-mentioned compounds adsorb on the silver surface through the thioether atom and that the attachment of Trp8 produces limitation in a number of possible C-S conformers adopted on this surface. Our results also show clearly that His12 and CO do not interact with the colloid surface, which supports our earlier results. 相似文献