Terahertz spectroscopic images of paraffin-embedded cancer tissues have been measured by a terahertz time domain spectrometer. For the systematic identification tumors, principal component analysis and clustering were applied. In three four samples, tissue was recognized as an aggregate data points in plots. By agglomerative hierarchical clustering, well categorized into other tissues. This method can be also applied to various kinds automatic discrimination plural components imaging.

Temperature-dependent terahertz (THz) absorption spectra of poly(3-hydroxyalkanoate)s (PHAs) were measured by using a Fourier transform far-infrared (FT-FIR) spectrometer and THz time-domain over temperature range 10 K to 465 with liquid helium cryostat heating cell. Clear differences observed between the crystalline amorphous polyhydroxybutyrate (PHB), indicating that peaks in originated higher-order conformation PHB. The polarization stretched PHB sample measured, direction vibrational...

Polymerization of monomeric actin into filaments has pivotal roles in cell motility, growth, differentiation, and gene expression. Therefore, techniques manipulating polymerization, including actin-binding chemicals, have been developed for understanding regulating multiple biological functions. Here, we demonstrate that irradiation with terahertz (THz) waves is a novel method modulating polymerization. When polymerization reaction performed under 0.46 THz generated by Gyrotron, was observed...

The effect of terahertz (THz) radiation on deep tissues human body has been considered negligible due to strong absorption by water molecules. However, we observed that the energy THz pulses transmits a millimeter thick in aqueous solution, possibly as shockwave, and demolishes actin filaments. Collapse filament induced irradiation was also living cells under an medium. We confirmed viability cell not affected exposure pulses. potential waves invasive method alter protein structure is demonstrated.

Recently, terahertz wave imaging has been shown to have potential in medical and biological applications. However, absorption by liquid water tissues hinders the measurement of thick samples. In this study, porcine tissue was frozen temperatures below −33 °C prevent absorption. Consequently, striated muscle adipose could be clearly distinguished time-domain spectra owing difference absorbance values refractive indices. We demonstrated two-dimensional map pulse delay, which shows spatial...

Using the high penetrability of terahertz waves and characteristic absorption spectra in this frequency range, we have built a noninvasive mail inspection system targeting drugs explosives. The is composed two stages; first stage, scattering continuous wave used for selecting that contains concealed powder; second spectrum suspicious measured material identified using database. We evaluated performance limits system.

Terahertz absorption spectra of poly(3-hydroxyalkanoates) with different conformations were measured by using a terahertz time domain spectrometer. Sharp peaks observed in the spectrum crystalline samples. The orientation direction transition dipole moment was investigated polarization spectra. peak at 2.92 THz assigned to vibration helical structure along fiber axis, and 2.49 attributed due hydrogen bonding between helix structures. temperature dependence reflects change distance melting...

Low-frequency vibrational bands observed in the Raman and terahertz (THz) spectra region of 50-150 cm(-1) crystalline powder poly-(R)-3-hydroxybutyrate (PHB) were assigned based on comparisons THz spectra, polarization directions absorption their congruities to quantum mechanically (QM) calculated spectra. This combination, spectroscopies QM simulations, has been rarely adopted spite its potential reliable assignments bands. The simulation a spectrum already popular spectroscopies, but for...

This paper reviews our recent spectroscopic study on poly(3-hydroxybutyrate) (PHB) for the terahertz (THz) frequency region. Clear differences are observed between absorption spectra of crystalline and amorphous PHB, indicating that higher order conformation PHB determines THz spectra. The polarization measured a stretched sample directions vibrational transition moments determined. found to have temperature dependences owing which peaks at lower frequencies shift with temperature,...

Abstract As terahertz (THz) frequencies correspond to those of the intermolecular vibrational modes in a polymer, intense THz wave irradiation affects macromolecular polymorph, which determines polymer properties and functions. photon energy is quite low compared covalent bond energy; therefore, conformational changes can be induced “softly,” without damaging chemical structures. Here, we irradiate poly(3-hydroxybutylate) (PHB) / chloroform solution during solvent casting crystallization...

We present high resolution (∼0.01 cm−1) infrared absorption spectra of the ν4 band methane doped parahydrogen (CH4/pH2) solids produced by two different techniques: gas condensation in an enclosed cell at T≈8 K, and rapid vapor deposition onto a T≈2 K substrate vacuum. The spectrum deposited solid contains novel progression single peaks with ≈5 cm−1 spacing, superimposed over known CH4 molecules trapped sites D3h symmetry hexagonal close-packed (hcp) pH2. New theoretical calculations...

Low-frequency vibrational modes of lamellar crystalline poly(glycolic acid) (PGA) were measured on Raman and far-infrared (FIR) spectra. Among the observed bands, an FIR band at ∼70 cm–1 a 125 showed gradual lower-frequency shift with increasing temperature from 20 °C to melting point ∼230 °C. Their polarization direction was perpendicular chain axis PGA. Both spectra quantum-mechanically simulated aid fragment method, Cartesian-coordinate tensor transfer, which enabled explicit...

Cellulose is a common polymer found in natural sources, with the potential to be used wide variety of green and technologically-relevant applications. Despite years effort, precise 3D structure two crystalline polymorphs cellulose, I_alpha I_beta, are currently still unknown due presence disorder intermolecular hydrogen bond networks, hampering an in-depth understanding structure-property relation this material. Disorder networks cellulose I was investigated terahertz spectroscopy, powder...

The isothermal crystallization of poly(3-hydroxybutylate) (PHB) was studied by monitoring the temporal evolution terahertz absorption spectra in conjunction with spectral analysis using two-dimensional correlation spectroscopy. Correlation between peaks and sequential order changes intensity extracted from synchronous asynchronous plots indicated that PHB at 90 °C is a two step process, which C-H···O=C hydrogen bonds are initially formed before well-defined crystal structures established.

Abstract We demonstrate photoacoustic wave propagation with a plane wavefront in liquid water using terahertz (THz) laser pulse. The THz light can effectively generate the because of strong absorption via stretching vibration mode hydrogen bonding network. excitation large-area surface irradiated by loosely focused produces wave. This is contrast conventional methods absorbers or plasma generation near-infrared light. and are observed system free-electron shadowgraph imaging. generated...

Herein, differences in the intermolecular interactions and flexibility between poly(ethylene terephthalate) (PET) poly(butylene (PBT) are studied by far-infrared, terahertz (THz), low-frequency Raman spectroscopy quantum chemical calculations (QCCs). Interatomic distance based on reported crystal structures natural bond orbital analysis indicate that PBT exhibits hydrogen bonding a C═O group CH2 adjacent molecular chains, while PET does not have such bonding. The results of infrared...

Far-infrared (FIR) and low-frequency Raman bands in the 90–400 cm–1 region of crystalline nylon 6 α form were assigned based on comparisons experimental spectra quantum mechanical calculations. A fragment methodology was applied calculations for explicit consideration interchain interactions crystal symmetry. The main features both FIR reproduced well, which enabled band assignments density functional theory significant improvement conventional there had been a big dispute. Temperature...

This work studies the renormalization of molecular moments inertia IG in liquid helium. For this purpose we have measured rotational-vibrational spectra ν3 modes a series homologous light spherical top molecules such as CH4, CD4, SiH4, and SiD4 He droplets. The were fitted to an empirical gas phase Hamiltonian, yielding set spectroscopic constants. We found that additional moment inertia, ΔIHe, scales approximately square IG. is agreement with theoretical model which assigns ΔIHe coupling...

Abstract Terahertz (THz) absorption spectra of cross-linked polyurethane films were observed at 30–180 °C. The obtained displayed characteristic bands. A band 2.6 THz was assigned to the C=O···N-H hydrogen bond vibration using previously reported data. DFT calculation results confirmed that a 7.5 arises owing torsional molecules containing urethane bonds. slight changes in temperature-dependent analyzed by first derivative intensity with temperature. thermal behavior intensities indicates...