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71.
72.
Fukuma H Nakashima K Ozaki Y Noda I 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):517-522
Generalized two-dimensional (2D) fluorescence correlation spectroscopy has been used to resolve the fluorescence spectra of two tryptophan (Trp) residues in alcohol dehydrogenase and lysozyme. In each protein, one Trp residue is buried in a hydrophobic domain of the protein matrix and the other Trp residue is located at a hydrophilic domain close to the protein-water interface. Fluorescence quenching by iodide ion, a hydrophilic quencher, was employed as a perturbation to induce the intensity change in the spectra. The Trp residue which is located at the hydrophilic domain is effectively quenched by the quencher, while the Trp residue located at the hydrophobic domain is protected from the quenching. Therefore, the fluorescence of these two Trp residues have a different sensitivity to the quenching, showing a different response to the concentration of the quencher. Fluorescence spectra of the two Trp residues in alcohol dehydrogenase, which are heavily overlapped in conventional one-dimensional spectra, have been successfully resolved by the 2D correlation technique. From the asynchronous correlation map, it was revealed that the quenching of Trp located at the hydrophobic part was brought about after that of Trp located at the hydrophilic part. In contrast, the fluorescence spectra of the two Trp residues could not be resolved after the alcohol dehydrogenase was denatured with guanidine hydrochloride. These results are consistent with the well-known structure of alcohol dehydrogenase. Furthermore, it was elucidated that the present 2D analysis is not interfered by Raman bands of the solvent, which sometimes bring difficulty into the conventional fluorescence analysis. Fluorescence spectra of the Trp residues in lysozyme could not be resolved by the 2D correlation technique. The differences between the two proteins are attributed to the fact that the Trp residue in the hydrophobic site of lysozyme is not sufficiently protected from the quenching. 相似文献
73.
Li YM Sun SQ Zhou Q Tao JX Noda I 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(3):565-573
Using FT-IR and 2D-IR correlation spectroscopy, the intensity changes and their sequence of amide I and II bands of four traditional Chinese animal drugs (Cornu Cervi Pantotrichum, Cornu Saigae Tataricae, Scorpio and Hirud) under thermal perturbation are studied, and component of Ca(3)(PO(4))(2) in the drug of Cornu Cervi Pantotrichum and sulfates components in the drug of scorpion are identified. The drug of Cornu Cervi Pantotrichum contains inorganic salt Ca(3)(PO(4))(2) and the drug of Scorpio contains sulfates. It is assigned that the bands of 604 and 561 cm(-1) belong to the component of Ca(3)(PO(4))(2), and the bands of 637 and 615 cm(-1) belong to sulfates. Organic components of these drugs respond to the thermal perturbation far stronger than that of the inorganic components. The intensities of amide I and II bands in the drugs, except for amide II band in drug Scorpio, change strongly. For the drugs of Cornu Cervi Pantotrichum, Cornu Saigae Tataricae and Hirudo, the intensity changes of amide II band occurs prior to that of amide I band. The C-N bond in the product operator(3)(4) conjugative system converts from double bond to single bond, but the C=O bond remains double bond during the heating process. On the other hand, amide II vibrations, which may involve much more of the hydrogen bonded local structures of amide groups in the system compared to the C=O dominated amide I vibration, may undergo thermally induced changes at a temperature much lower than the other mode. The traditional Chinese animal drugs can be identified rapidly and non-separately by using FT-IR and 2D-IR correlation spectroscopy. 相似文献
74.
Debasish Ghosh Pradip Ghosh Golap Kalita Takuto Noda Chisato Takahashi Masaki Tanemura 《固体物理学:研究快报》2013,7(7):489-492
An efficient cathode material with high transparency (93%) based on conducting polymer poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and single wall carbon nanotubes (SWCNTs) has been developed for the fabrication of highly transparent and flexible field electron emitters (FEE). This kind of material showed superior field emission (FE) performance with very high current density (10–3A/cm2) at very low electric field. The FE performance of the hybrid materials was dramatically improved compared to either SWCNTs and PEDOT:PSS. Thus the hybrid structures of conducting polymer and SWCNTs might be a good choice for use as a cathode material to enhance the FE performance and for potential application in future portable displays. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
75.
L. Shao D. Shao C. G. Shao H. Noda 《International Journal of Theoretical Physics》2008,47(6):1663-1691
Using the recoupling theorem and graph calculation in loop quantum gravity, it is demonstrated that the action of metric matrix
operator on Gaussian weave state is an eigenaction, the representation matrix elements of the metric operator and their expectation
values are calculated. The values of length of tangent vectors of edges adjacent to the vertex of Gaussian weave state, as
well as the angles between them are also obtained in the cases of k=0 and k=2. 相似文献
76.
Direct Estimation of the Surface Location of Immobilized Functional Groups for Concerted Catalysis Using a Probe Molecule
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Hiroto Noda Dr. Ken Motokura Prof. Dr. Yusuke Wakabayashi Kaori Sasaki Dr. Hiroo Tajiri Dr. Akimitsu Miyaji Dr. Sho Yamaguchi Prof. Dr. Toshihide Baba 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5113-5117
The location of active sites during concerted catalysis by a metal complex and tertiary amine on a SiO2 surface is discussed based on the interaction between the functionalized SiO2 surface and a probe molecule, p‐formyl phenylboronic acid. The interactions of the probe molecule with the surface functionalities, diamine ligand, and tertiary amine, were analyzed by FT‐IR and solid‐state 13C and 11B MAS NMR. For the catalyst exhibiting high 1,4‐addition activity, the diamine ligand and tertiary amine base exist in closer proximity than in the catalyst with low activity. 相似文献
77.
Choi HC Lee S Lee KK Noda I Park C Kwon CH Jung YM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(4):1110-1113
A promising possibility for the quantitative analysis of X-ray absorption near edge structure (XANES) spectra of nanosized electrode materials is demonstrated. We used a 2D map representation technique, which utilizes the values of the first derivatives of the absorbance with respect to the inserted Li(+) content plotted over the two-dimensional space defined by the inserted Li(+) content (mole) versus photon energy (eV) as a single map. The technique was applied to XANES spectra of the Li(y)CoO system in the first Li(+) insertion reaction for determining the structural and electronic variations associated with the change in Li(+) content. The obtained show that the intensities of two peaks at 7725 and 7711 eV increased with the Li(+) content and the difference of intensity change of these two peaks carried out for successive couples of spectra yielded the largest changes at 1.05 and 1.98 mol of Li content. This approach for quantitative analysis of XANES without using conventional simulation techniques enable us to interpret X-ray absorption spectroscopy (XAS) as a quantitative analytical technique with greater confidence. 相似文献
78.
Dr. Xinxin Tang Dr. Hidetoshi Noda Prof. Dr. Masakatsu Shibasaki 《Angewandte Chemie (International ed. in English)》2023,62(51):e202311027
The exponential proliferation of conformers makes it impossible to examine the entire population in most systems. Controlling conformational ensembles is thus pivotal in many areas of chemistry. Rh2(esp)2, a dicarboxylate-derived paddlewheel rhodium complex, is one of the most effective catalysts for nitrene chemistry. Its enormous success has led to preparing many analogous complexes. However, there has been little consideration for the conformational dynamics of the parent catalyst. Herein, we report a new ligand modification principle that prevents conformer interconversion. The resulting complex comprises two isolable conformers, whose structures have been determined by X-ray diffraction. Combined experimental and computational data has revealed similarities and dissimilarities between the conformationally confined and parent complexes. Three model cases have demonstrated the utility of conformational fixation in the development of stereoselective catalysts for nitrene transfer reactions. The design principle described in this study can be combined with other established modification strategies, serving as a springboard for further advancement of the chemistry of paddlewheel metal complexes. 相似文献
79.
Noda N Tani H Morita N Kurata S Nakamura K Kanagawa T Tsuneda S Sekiguchi Y 《Analytica chimica acta》2008,610(2):211-216
A modified solvent microextraction with back extraction method (SME/BE) combined with high performance liquid chromatography and fluorescence detection (HPLC-FD) was developed for the determination of citalopram in human plasma. Extraction process was performed in a home-made total glass vial without using a teflon ring, usually employed in SME/BE. Citalopram was first extracted from 0.5 mL of plasma, modified with sodium hydroxide, into hexane. Back extraction step was then performed into 5.2 μL of 45 mM ammonium formate solution (pH 4) using a GC microsyringe. The extract was subsequently transferred into a liner-like vial and then injected into the HPLC system. An enrichment factor of 150 along with a good sample clean-up was obtained. The calibration curve showed linearity in the range of 1.0–130.0 ng mL−1 with regression coefficient corresponding to 0.992. This range covers therapeutic window and even lower amounts which is important in pharmacokinetic studies. Limits of detection and quantification, based on a signal to noise ratio (S/N) of 3 and 10, were 0.3 and 0.8 ng mL−1, respectively. The method was also applied for the determination of citalopram in plasma samples after oral administration of 40 mg single dose of citalopram. 相似文献
80.
Takumi Noda 《The Ramanujan Journal》2016,41(1-3):183-190
A zeta-function associated with Kummer’s confluent hypergeometric function is introduced as a classical Dirichlet series. An integral representation, a transformation formula, and relation formulas between contiguous functions and one generalization of Ramanujan’s formula are given. The inverse Laplace transform of confluent hypergeometric functions is essentially used to derive the integral representation. 相似文献