Takeshi Hasegawa | Kyoto University (original) (raw)
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Papers by Takeshi Hasegawa
Physical Chemistry Chemical Physics, 2015
The molecular structure of poly(3-alkylthiophene-2,5-diyl) in an amorphous film reveals that the ... more The molecular structure of poly(3-alkylthiophene-2,5-diyl) in an amorphous film reveals that the short axis of the thiophene ring is parallel to the substrate, whereas the long axis along the polymer chain is largely disordered. This is unveiled by infrared p-polarized multiple-angle incidence resolution spectroscopy.
AIP Conference Proceedings, 2000
Monolayer formation mechanism of α-mycolic acid (α-MA) isolated from Mycobacterium bovis BCG Past... more Monolayer formation mechanism of α-mycolic acid (α-MA) isolated from Mycobacterium bovis BCG Pasteur strain was investigated by infrared reflection-absorption (IRRA) spectrometry with two-dimensional (2D) correlation analysis. The raw IRRA spectra did not characterize the precise feature of the MA monolayer. 2D correlation analysis, however, clearly revealed that the longer or the major chain of the MA stood up earlier than the shorter chain or the α-alkyl group when the monolayer was compressed, and that the upright chains were in the form of ordered conformation.
Chemical Physics Letters, 2015
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 5, 2017
The pH dependent chemical structures of bromothymol blue (BTB), which have long been under contro... more The pH dependent chemical structures of bromothymol blue (BTB), which have long been under controversy, are determined by employing a combined technique of multivariate analysis of electronic absorption spectra and quantum chemistry. Principle component analysis (PCA) of the pH dependent spectra apparently reveals that only two chemical species are adequate to fully account for the color changes, with which the spectral decomposition is readily performed by using augmented alternative least-squares (ALS) regression analysis. The quantity variation by the ALS analysis also reveals the practical acid dissociation constant, pKa'. The determination of pKa' is performed for various ionic strengths, which reveals the thermodynamic acid constant (pKa=7.5) and the number of charge on each chemical species; the yellow form is negatively charged species of -1 and the blue form that of -2. On this chemical information, the quantum chemical calculation is carried out to find that BTB mo...
Analytical and Bioanalytical Chemistry, 2014
Handbook of Vibrational Spectroscopy, 2006
The sections in this article are Introduction Data Modeling by Latent Variables Decomposition of ... more The sections in this article are Introduction Data Modeling by Latent Variables Decomposition of Spectral Data Using Latent Variables Least Squares Regression by Matrix Algebra “Partial” CLS to Yield a Principal Component Principal Component Regressions Comparison of CLS and ILS Generate Factors by PCA for ILS Protocols of PCR Calculation Steps of PCR Calibration Calculation Steps for Concentration Prediction by PCR Selection of Significant Factors Analysis of Error Empirically Defined Method of Error Estimation Statistical Method for Error Estimation Selection by Validation Abstract Spectra and Residuals Optional Pretreatment Mean Centering Scaling Normalization Partial Least Squares Regression PLS2 (Global PLS) PLS2 Calibration Discussion of the PLS2 Algorithm Selection of Basis Factors for PLS Modeling PLS Prediction PLS Modeling by Eigenvector Calculation PLS1 (Standard PLS) Comparison of PLS2 with PLS1 Comparison of PLS with PCR
Analytical and bioanalytical chemistry, 2003
The Journal of Physical Chemistry B, 1999
The Journal of Physical Chemistry B, 2008
A synthesized peptidolipid (C18IIGLM-NH2) comprised of a single C18-saturated hydrocarbon chain c... more A synthesized peptidolipid (C18IIGLM-NH2) comprised of a single C18-saturated hydrocarbon chain connected to the amino acid sequence IIGLM terminated with the NH2 group was spread on water, which formed a stable Langmuir monolayer. The Langmuir and Langmuir-Blodgett (LB) films have been characterized by measurements of surface pressure-area (pi-A) and surface potential-area (DeltaV-A) isotherms and infrared multiple-angle incidence resolution spectrometry (MAIRS). The Langmuir monolayer had a significantly larger limiting molecular area than that of a similar molecule of C18IIGLM-OH, which was reported in our previous study. The surface dipole moment analysis coupled with the pi-A isotherm suggested that the C18IIGLM-NH2 monolayer was extraordinarily stiff and the fundamental structure of the monolayer was brought about before the monolayer compression. The infrared MAIRS analysis of the C18IIGLM-NH2 LB film revealed that the backbone structure of the monolayer was the 'antiparallel' beta sheet aligned parallel to the substrate. Since the C18IIGLM-OH LB film was made of 'parallel' beta sheet with a random orientation, it has been found that the present C18IIGLM-NH2 Langmuir monolayer has a largely different monolayer structure, although the chemical structures are slightly different from each other by the terminal group only.
The Journal of Physical Chemistry B, 2007
A synthetic peptidolipid consisted of a hydrocarbon chain with a chain length of C18 and a peptid... more A synthetic peptidolipid consisted of a hydrocarbon chain with a chain length of C18 and a peptide moiety of IIGLM terminated with an amine group, designated as C18IIGLM-NH2, has been employed as a biomimic model compound of amyloid peptide for exploring molecular interaction and orientation with the use of the Langmuir monolayer and Langmuir-Blodgett film techniques. Inspired by a well-known fact that a stain reagent, Congo red (CR), binds well to the amyloid-mimic part (IIGLM), inhibition of molecular aggregation of C18IIGLM-NH2 by interaction with CR was expected, and it has been investigated by use of surface pressure-area isotherm, surface dipole moment-area isotherm, Brewster-angle microscopy, and UV-vis/infrared spectroscopies. It has been revealed that monomeric CR molecules whose long axis is parallel to the Langmuir monolayer surface are penetrating the C18IIGLM-NH2 Langmuir monolayer, which plays a role of inhibition of molecular aggregation via hydrogen bonding.
The Journal of Physical Chemistry B, 2001
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 1998
Physical Chemistry Chemical Physics, 2015
The molecular structure of poly(3-alkylthiophene-2,5-diyl) in an amorphous film reveals that the ... more The molecular structure of poly(3-alkylthiophene-2,5-diyl) in an amorphous film reveals that the short axis of the thiophene ring is parallel to the substrate, whereas the long axis along the polymer chain is largely disordered. This is unveiled by infrared p-polarized multiple-angle incidence resolution spectroscopy.
AIP Conference Proceedings, 2000
Monolayer formation mechanism of α-mycolic acid (α-MA) isolated from Mycobacterium bovis BCG Past... more Monolayer formation mechanism of α-mycolic acid (α-MA) isolated from Mycobacterium bovis BCG Pasteur strain was investigated by infrared reflection-absorption (IRRA) spectrometry with two-dimensional (2D) correlation analysis. The raw IRRA spectra did not characterize the precise feature of the MA monolayer. 2D correlation analysis, however, clearly revealed that the longer or the major chain of the MA stood up earlier than the shorter chain or the α-alkyl group when the monolayer was compressed, and that the upright chains were in the form of ordered conformation.
Chemical Physics Letters, 2015
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 5, 2017
The pH dependent chemical structures of bromothymol blue (BTB), which have long been under contro... more The pH dependent chemical structures of bromothymol blue (BTB), which have long been under controversy, are determined by employing a combined technique of multivariate analysis of electronic absorption spectra and quantum chemistry. Principle component analysis (PCA) of the pH dependent spectra apparently reveals that only two chemical species are adequate to fully account for the color changes, with which the spectral decomposition is readily performed by using augmented alternative least-squares (ALS) regression analysis. The quantity variation by the ALS analysis also reveals the practical acid dissociation constant, pKa'. The determination of pKa' is performed for various ionic strengths, which reveals the thermodynamic acid constant (pKa=7.5) and the number of charge on each chemical species; the yellow form is negatively charged species of -1 and the blue form that of -2. On this chemical information, the quantum chemical calculation is carried out to find that BTB mo...
Analytical and Bioanalytical Chemistry, 2014
Handbook of Vibrational Spectroscopy, 2006
The sections in this article are Introduction Data Modeling by Latent Variables Decomposition of ... more The sections in this article are Introduction Data Modeling by Latent Variables Decomposition of Spectral Data Using Latent Variables Least Squares Regression by Matrix Algebra “Partial” CLS to Yield a Principal Component Principal Component Regressions Comparison of CLS and ILS Generate Factors by PCA for ILS Protocols of PCR Calculation Steps of PCR Calibration Calculation Steps for Concentration Prediction by PCR Selection of Significant Factors Analysis of Error Empirically Defined Method of Error Estimation Statistical Method for Error Estimation Selection by Validation Abstract Spectra and Residuals Optional Pretreatment Mean Centering Scaling Normalization Partial Least Squares Regression PLS2 (Global PLS) PLS2 Calibration Discussion of the PLS2 Algorithm Selection of Basis Factors for PLS Modeling PLS Prediction PLS Modeling by Eigenvector Calculation PLS1 (Standard PLS) Comparison of PLS2 with PLS1 Comparison of PLS with PCR
Analytical and bioanalytical chemistry, 2003
The Journal of Physical Chemistry B, 1999
The Journal of Physical Chemistry B, 2008
A synthesized peptidolipid (C18IIGLM-NH2) comprised of a single C18-saturated hydrocarbon chain c... more A synthesized peptidolipid (C18IIGLM-NH2) comprised of a single C18-saturated hydrocarbon chain connected to the amino acid sequence IIGLM terminated with the NH2 group was spread on water, which formed a stable Langmuir monolayer. The Langmuir and Langmuir-Blodgett (LB) films have been characterized by measurements of surface pressure-area (pi-A) and surface potential-area (DeltaV-A) isotherms and infrared multiple-angle incidence resolution spectrometry (MAIRS). The Langmuir monolayer had a significantly larger limiting molecular area than that of a similar molecule of C18IIGLM-OH, which was reported in our previous study. The surface dipole moment analysis coupled with the pi-A isotherm suggested that the C18IIGLM-NH2 monolayer was extraordinarily stiff and the fundamental structure of the monolayer was brought about before the monolayer compression. The infrared MAIRS analysis of the C18IIGLM-NH2 LB film revealed that the backbone structure of the monolayer was the 'antiparallel' beta sheet aligned parallel to the substrate. Since the C18IIGLM-OH LB film was made of 'parallel' beta sheet with a random orientation, it has been found that the present C18IIGLM-NH2 Langmuir monolayer has a largely different monolayer structure, although the chemical structures are slightly different from each other by the terminal group only.
The Journal of Physical Chemistry B, 2007
A synthetic peptidolipid consisted of a hydrocarbon chain with a chain length of C18 and a peptid... more A synthetic peptidolipid consisted of a hydrocarbon chain with a chain length of C18 and a peptide moiety of IIGLM terminated with an amine group, designated as C18IIGLM-NH2, has been employed as a biomimic model compound of amyloid peptide for exploring molecular interaction and orientation with the use of the Langmuir monolayer and Langmuir-Blodgett film techniques. Inspired by a well-known fact that a stain reagent, Congo red (CR), binds well to the amyloid-mimic part (IIGLM), inhibition of molecular aggregation of C18IIGLM-NH2 by interaction with CR was expected, and it has been investigated by use of surface pressure-area isotherm, surface dipole moment-area isotherm, Brewster-angle microscopy, and UV-vis/infrared spectroscopies. It has been revealed that monomeric CR molecules whose long axis is parallel to the Langmuir monolayer surface are penetrating the C18IIGLM-NH2 Langmuir monolayer, which plays a role of inhibition of molecular aggregation via hydrogen bonding.
The Journal of Physical Chemistry B, 2001
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 1998