A5081439764- Spectroscopy and Quantum Chemical Studies
- Molecular spectroscopy and chirality
- Photoreceptor and optogenetics research
- Spectroscopy and Laser Applications
- Photochemistry and Electron Transfer Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Mass Spectrometry Techniques and Applications
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Advanced Chemical Physics Studies
- Laser-Matter Interactions and Applications
- Electron Spin Resonance Studies
- Chemical Synthesis and Analysis
- ZnO doping and properties
- Magnetic properties of thin films
- Gold and Silver Nanoparticles Synthesis and Applications
- Metal and Thin Film Mechanics
- Advanced Fiber Laser Technologies
- melanin and skin pigmentation
- Photonic Crystal and Fiber Optics
- Plasmonic and Surface Plasmon Research
- RNA and protein synthesis mechanisms
- Mining and Gasification Technologies
- Pulsed Power Technology Applications
University of California System
2025
University of California, Irvine
2006-2021
Tokyo University of Science
2019
Osaka University
2007-2012
Kobe University
2000-2005
Nagoya University
2003
Toshiba (Japan)
2002
Nagaoka University
1996-1998
Nagaoka University of Technology
1996-1998
Tokyo Institute of Technology
1993-1994
We demonstrate a phase sensitive, vibrationally resonant sum-frequency generation (PSVR-SFG) microscope that combines high resolution, fast image acquisition speed, chemical selectivity, and sensitivity. Using the PSVR-SFG microscope, we generate amplitude images of second-order susceptibility collagen I fibers in rat tail tendon tissue on resonance with methylene vibrations protein. find shows dependence effective polarity fibril bundles, revealing fibrous domains opposite orientations...
Short peptides are important as lead compounds and molecular probes in drug discovery chemical biology, but their well-known drawbacks, such high conformational flexibility, protease lability, poor bioavailability short half-lives vivo, have prevented potential from being fully realized. Side chain-to-side chain cyclization, e.g., by ring-closing olefin metathesis, known stapling, is one approach to increase the biological activity of that has shown promise when applied 310- α-helical...
BiVO4 photoanodes are promising for solar water splitting, with photogenerated electrons and holes preferentially reacting at top {010} lateral {110} facets, respectively. However, the mechanisms driving this facet-dependent reactivity remain unclear. Here, we investigate photocurrent material heterogeneity using correlative scanning photoelectrochemical microscopy (SPCM), electron beam induced current (EBIC) mapping, mid-IR scattering near-field optical (s-SNOM). SPCM measurements of 62...
We have carried out a comparative study of five ab initio electrostatic frequency maps and semiempirical model for the amide-I -II modes. Unrestrained molecular dynamics simulation 310-helical peptide, Z-Aib-l-Leu-(Aib)2-Gly-OtBu, in CDCl3 is performed using AMBER ff99SB force field, linear two-dimensional infrared (2D IR) spectra are simulated on basis vibrational exciton Hamiltonian model. A new potential-based map N-methylacetamide developed this study. This other by different research...
Two-dimensional infrared (2D IR) spectra of Cα-alkylated model octapeptides Z-(Aib)8-OtBu, Z-(Aib)5-l-Leu-(Aib)2-OMe, and Z-[l-(αMeVal)]8-OtBu have been measured in the amide I region to acquire 2D spectral signatures characteristic 310- α-helical conformations. Phase-adjusted absorptive recorded with parallel polarizations are dominated by intense diagonal peaks, whereas rephasing obtained at double-crossed polarization configuration reveal cross-peak patterns that essential for structure...
We have carried out structural determination of capped Cα,α-diethylglycine (Deg) homopeptides with different chain lengths, Ac-(Deg)n-OtBu (n = 2−5), solvated in CDCl3, and investigated vibrational properties the amide I II modes by linear 2D IR spectroscopy, ONIOM calculations, molecular dynamics simulations. experiments were performed region using rephasing pulse sequence under double-crossed polarization nonrephasing a new configuration to measure cross-peak patterns off-diagonal regions....
We have investigated the onset of secondary structure and evolution two-dimensional infrared (2D IR) spectral patterns as a function chain length with study 310-helical peptides. The results show that 2D IR is highly sensitive to peptide conformation, disorder, size. An extensive set spectra Cα-methylated homopeptides, Z-(Aib)n-OtBu (n = 3, 5, 8, 10), in CDCl3 was measured amide-I region. tripeptide are quite different from those longer signatures begin converge at pentapeptide become almost...
Vibrational couplings between the amide modes are keenly dependent on peptide structure. Site-specific can inform us of molecular conformation in detail. For example, when an amide-I mode couples to amide-II that is three residues away because they brought into proximity presence intramolecular C═O···H−N hydrogen bond, coupling provide direct evidence for single helical turn formation, a proposed key step coil−helix transition. In this work, we measure 2D IR spectra 310-helical hexapeptide,...
We have investigated the sensitivity of two-dimensional infrared (2D IR) spectroscopy to peptide helicity with an experimental and theoretical study Z-[l-(αMe)Val]8-OtBu in CDCl3. 2D IR experiments were carried out amide-I region under parallel double-crossed polarization configurations. In latter configuration, spectra taken rephasing nonrephasing pulse sequences exhibit a doublet feature single peak, respectively. These cross-peak patterns are highly sensitive underlying structure....
We have combined two-dimensional infrared (2D IR) spectroscopy and isotope substitutions to reveal the vibrational couplings between a pair of amide-I -II modes that are several residues away but directly connected through hydrogen bond in helical peptide. This strategy is demonstrated on 310-helical hexapeptide, Z-Aib-l-Leu-(Aib)2-Gly-Aib-OtBu, its 13C═18O-Leu monolabeled 13C═18O-Leu/15N-Gly bis-labeled isotopomers CDCl3. The isotope-dependent amide-I/II cross peaks clearly show second...
Third-order nonlinear IR spectroscopy has been used to study the vibrational population relaxation and dephasing dynamics of CN stretching mode Fe(CN)64- in D2O. Transient-grating signals magic-angle condition show a biexponential decay upon excitation T1u motion. A fast-decaying component (∼700 fs) transient-grating signal is attributed rapid equilibration between Raman-active modes. The time scale slow-decaying around 23 ps, which corresponds from v = 1 state mode. Anisotropy decays with...
A new type of non-innocent β-diketiminate ligand having redox active phenol groups (LH33, fully protonated form) has been developed, and the structure, physical properties reactivity supported copper(II) complex [CuII(L3−3−)]− (L3−3−, deprotonated tri-anionic as well one-electron two-electron oxidised complexes, [CuII(L˙2−)] [CuII(L−−)]+, have examined in detail. The form [CuII(L−−)]+ exhibited hydrogen atom abstraction ability from 1,4-cyclohexadiene (CHD), whereas was found to...
In the developing field of nonlinear plasmonics, it is important to understand fundamental relationship between properties localized surface plasmon resonance (LSPR) metallic nanostructures and their optical responses. A detailed understanding responses from with well-characterized LSPRs an essential prerequisite for future design sophisticated plasmonic systems advanced functions control light. this article, we investigate second-order harmonic (SH) gold nanocrescent (Au NC) antennas which...
Three-pulse infrared photon echo spectroscopy has been used to determine the correlation function of fluctuations vibrational frequencies OCN- and SCN- in methanol. The functions antisymmetric stretching modes for these two ions are fitted with a double exponential time constants around 100 fs 4 ps. amplitude is found be greater than that OCN-. We discuss difference spectral diffusion processes between
Fluctuation of the transition frequency anti-symmetric stretching mode azide ion in a nonionic reverse micelle was studied by infrared three-pulse photon echo method. The time correlation function fluctuation has three components. It is found that contribution static component much larger than bulk water, while other two components with faster constants are similar to those bulk.
We have used a combination of 2D IR spectroscopy with 13C═18O labeled amide-I and 15N-labeled amide-II modes to reveal how vibrational coupling between peptide units depends on secondary structure. Linear measurements simulations Cα,α-diethylglycine homotetrapeptide show that this compound adopts the fully extended (2.05-helical) conformation in CDCl3, consistent previous work Ac-capped peptide. The amide-I/II cross peaks isotopomers exhibit only marginal isotope frequency shift are...
Vibrationally resonant sum-frequency generation (VR SFG) microscopy is an advanced imaging technique that can map out the intensity contrast of infrared and Raman active vibrational modes with micron to submicron lateral resolution. To broaden its applications obtain a molecular level understanding, further technical advancement needed enable high-speed measurements VR SFG microspectra at every pixel. In this study, we demonstrate new hyperspectral platform combined ultrafast laser system...
Molecular conformations around the C═O group of carbonyl compounds like ketones and aldehydes play an important role in determining their reaction properties solutions, including rate, mechanism, steric structure, chirality products. Investigating different rotational conformers rapid exchange at room temperature will provide information on barrier insights into how rotamers may contribute to fundamental reactions chemistry. We applied two-dimensional infrared (2D IR) spectroscopy...
An influence of spin-transfer-induced resonant excitation a vortex magnetic domain wall on magnetization reversal process was investigated in Permalloy nanowires. Sizable reduction the depinning field observed under an application radio frequency current when coincided with resonance core. The found to increase by shrinking wire width. These results lead authors conclude that assists walls. This provides important insight for realization novel memory and logic devices based current-driven...
We have fabricated InGaAs/GaAs vertical-cavity surface-emitting lasers with modulation-doped graded distributed Bragg reflectors (DBRs) grown by metal-organic chemical vapor deposition (MOCVD). The threshold current was 3.2 mA. By observing the spontaneous emission through DBRs, we found that transverse mode behavior depends on gain characteristics. Single fundamental transverse-mode lasing is achieved at a negative offset and multiple positive offset.