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Yoshio Suzuki Noriyuki Tanji Chikako Ikeda Aki Honda Kenji Ookubo Daniel Citterio Suzuki Koji 《Analytical sciences》2004,20(3):475-482
Novel labeling reagents, called MS probes, which possess a positively charged quaternary amine moiety and can transform a neutral analyte into a charged compound by simply mixing with the analyte and allowing the mixture to stand from several minutes to 30 min at room temperature or while heating to 50 degrees C, were designed and synthesized for the highly sensitive detection of carbonyl, alcohol, carboxylic acid and primary amine samples by electrospray ionization mass spectrometry (ESI-MS). The positively charged products can be detected with high sensitivity in an ESI-MS system, which is the most popular liquid MS instrument. All of the labeled products showed a remarkably large increase in the molecular-ion peak abundance detection sensitivity of over 500-fold at picomolar concentration levels compared to that of unlabeled analytes in an ESI-MS system. These MS probes, used together with liquid MS detection, are widely applicable as a convenient method for the highly sensitive detection of less than picomolar levels of analytes, and therefore greatly enhance the power of ESI-MS analysis. 相似文献
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We demonstrate that molecules with a moderate permanent dipole moment can be oriented with combined electrostatic and pulsed, nonresonant laser fields. We use OCS molecules as a sample. The degree of orientation can be increased by increasing the magnitude of electrostatic field and the peak intensity of the laser field or by decreasing the rotational temperature of the molecules. 相似文献
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Y. Nakagawa Y. Tanji H. Morita H. Hiroyoshi H. Fujimori 《Journal of magnetism and magnetic materials》1979,10(2-3):145-151
Fe-Ni Invar alloys exhibit anomalies in thermodynamic and physical properties at high temperatures. This is considered to result from the tendency to two-phase separation in the fcc phase. This idea is supported also by interdiffusion experiments in the Fe-Ni system, where the interdiffusion coefficient is anomalously small in the Invar region at lower temperatures. A simple theory of regular solutions based on a pair interaction model is applied to the Fe-Ni system; with the assumption of two gamma states this gives a miscibility gap in the Invar region. 相似文献
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In order to understand the mechanisms of action of cosmetic ingredients, it is important to establish the distribution of the component agents within the epidermis of the skin. To date, time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been used to detect cosmetic ingredients in the skin. However, it is technically difficult to investigate the distribution of the agents in the stratum corneum using TOF-SIMS. Therefore, an analytical method with higher spatial resolution is required. In this study, we investigated an imaging analysis technique based on NanoSIMS to detect cosmetic ingredients in the skin. Pig skin was used as a model for human skin. The sample was treated with a cosmetic formulation containing 15N-labelled pseudo-ceramide (SLE). The sample was frozen with liquid nitrogen and cross-sections were cut using a cryomicrotome. As a result, the fine layer structure of the corneocytes was clearly observed by using NanoSIMS. Our studies indicate that SLE penetrates into the stratum corneum via an intercellular route. We conclude that application of NanoSIMS analysis can contribute to a better understanding of the function of cosmetic ingredients in the skin. 相似文献
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Steric Effect of Carboxylate Ligands on Pd‐Catalyzed Intramolecular C(sp2)–H and C(sp3)–H Arylation Reactions 下载免费PDF全文
Yutaka Tanji Naoya Mitsutake Prof. Dr. Tetsuaki Fujihara Prof. Dr. Yasushi Tsuji 《Angewandte Chemie (International ed. in English)》2018,57(32):10314-10317
A bulky carboxylic acid bearing three cyclohexylmethyl substituents at the α‐position, namely, tri(cyclohexylmethyl)acetic acid, is demonstrated to act as an efficient ligand source in Pd‐catalyzed intramolecular C(sp2)?H and C(sp3)?H arylation reactions. The reactions proceed smoothly under mild reaction conditions, even at room temperature due to the steric bulk of the carboxylate ligands, which accelerates the rate‐determining C?H bond activation step in the catalytic cycle. 相似文献
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Shigeyasu Tanaka Yoshio Honda Norifumi Kameshiro Ryuta Iwasaki Nobuhiko Sawaki Takayoshi Tanji Mikio Ichihashi 《Journal of Crystal Growth》2004,260(3-4):360-365
We have investigated the morphology of the high-temperature-grown AlN nucleation layer and its role in the early stage of GaN growth, by means of transmission electron microscopy. The nitride was selectively grown on a 7-degree off-oriented (0 0 1) patterned Si substrate by metalorganic vapor phase epitaxy. AlN was deposited on the inclined unmasked (1 1 1) facet in the form of islands. The size of the islands varied along the slope, which is attributable to the diffusion of the growth species in the vapor phase. The GaN nucleation occurred at the region where rounded AlN islands formed densely. The threading dislocations were observed to generate in the GaN nucleated region. 相似文献
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Conducting polymer poly(pyrrole) (PPy) doped with Nafion was successfully used as ion-to-electron transducer in the construction
of a solid-contact Pb2+-selective polymeric membrane electrode. The Nafion dopant can effectively increase the capacitance of the conducting polymer
and improve the mechanical robustness of the coating. The transducer layer, PPy-Nafion, characterized by cyclic voltammetry
and electrochemical impedance spectroscopy, exhibits a sufficiently high bulk (redox) capacitance and fast ion and electron
transport process. The new Pb2+-selective polymeric membrane electrode, based on PPy-Nafion film as solid contact, shows stable Nernstian characteristics
in Pb(NO3)2 solution within the concentration range of 1.0 × 10−7–1.0 × 10−3 M, and the detection limit is 4.3 × 10−8 M. The potential stability of the electrode and the influence of the interfacial water layer were also evaluated by chronopotentiometry
and potentiometric water layer test, respectively. The results show that the solid-contact Pb2+-selective electrode, based on PPy-Nafion film as ion-to-electron transducer, can effectively overcome the potential drift
and reduce the water layer between the PPy-Nafion transducer layer and the ion-selective membrane. 相似文献
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Redox reactions were studied at a single yttria-stabilized zirconia (YSZ)/Pt electrode interface, in parallel with pure YSZ with no catalyst electrode, by in situ analytical electron microscopy at elevated temperatures and in an oxygen atmosphere. In situ electron holography showed that the oxide underwent reduction at elevated temperatures in a vacuum and was consequently reoxidized upon exposure to an oxygen flux at the same temperature. In situ energy loss spectroscopy measurements were in agreement with in situ electron holography observations and indicated that the oxidation state of the host cation zirconium was altered in the reduced state of the YSZ to the metastable state Zr(3+). 相似文献
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Intramolecular [2+2] cycloaddition of γ,δ-unsaturated ketenes derived from hex-5-enoyl chloride derivatives gave bicyclo[2.1.1]hexan-5-ones with complete regioselectivity. 相似文献