Abstract-A Nondestructive Eggshell Thickness Measurement Technique Using Terahertz Waves

Alin Khaliduzzaman,  

Keiji Konagaya, 

Tetsuhito Suzuki, 

Ayuko Kashimori, 

Naoshi Kondo,  

Yuichi Ogawa

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https://www.nature.com/articles/s41598-020-57774-5

Eggshells play a number of important roles in the avian and reptile kingdom: protection of internal contents and as a major source of minerals for developing embryos. However, when researching these respective roles, eggshell thickness measurement remains a bottleneck due to the lack of a non-destructive measurement techniques. As a result, many avian and reptile research protocols omit consideration of eggshell thickness bias on egg or embryo growth and development. Here, we validate a non-destructive method to estimate eggshell thickness based on terahertz (THz) reflectance spectroscopy using chicken white coloured eggs. Since terahertz waves are reflected from outer air-eggshell interface, as well as the inner eggshell-membrane boundary, the resulting interference signals depend on eggshell thickness. Thus, it is possible to estimate shell thickness from the oscillation distance in frequency-domain. A linear regression-based prediction model for non-destructive eggshell thickness measurement was developed, which had a coefficient of determination (R2) of 0.93, RMSEP of 0.009, RPD of 3.45 and RER 13.67. This model can estimate eggshell thickness to a resolution of less than 10 μm. This method has the potential to expand the protocols in the field of avian and reptile research, as well as be applied to industrial grading of eggs.

Abstract-Hydration and Hydrogen Bond Network of Water during the Coil-to-Globule Transition in Poly(N-isopropylacrylamide) Aqueous Solution at Cloud Point Temperature

Keiichiro Shiraga , Hirotaka Naito , Tetsuhito Suzuki , Naoshi Kondo , and Yuichi Ogawa

J. Phys. Chem. B, Just Accepted Manuscript

DOI: 10.1021/acs.jpcb.5b01021

Publication Date (Web): April 12, 2015

Copyright © 2015 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/acs.jpcb.5b01021?journalCode=jpcbfk

Aqueous solution of poly(N-isopropylacrylamide), P-NIPAAm, exhibits a noticeable temperature responsive change in molecular conformation at a cloud point temperature (Tcp). As the temperature rises above Tcp, the extended coil-like P-NIPAAm structure changes into a swollen globule-like conformation as hydration levels decrease and hydrophobic interactions. Though water plays an important role in this coil-to-globule transition of P-NIPAAm, the behavior of water molecules and the associated hydrogen-bond (HB) network of the surrounding bulk water are still veiled in uncertainty. In this study, we elucidated changes in the hydration state and the dynamical structure of the water HB network of P-NIPAAm aqueous solutions, during the coil-to-globule transition, by analyzing the complex dielectric constant in the terahertz (THz) region (0.25~12 THz), where bulk water reorientations and intermolecular vibrations of water can be selectively probed. The structural properties of the water HB network were examined in terms of the population of the non-HB water molecules (not directly engaged in the HB network or hydrated to P-NIPAAm), and the tetrahedral coordination of the water molecules engaged in the HB network. We found the hydration number (≈10) below Tcp was decreased to approximately 6.5 as temperature increased, in line with previous studies. The HB network of bulk water becomes more structured as the coil-to-globule phase transition takes place, via decreases in non-HB water and reduction in the orderliness of the tetrahedral HB architecture. Together these results indicate that the coil-to-globule transition is associated with a shift to hydrophobic dominated interactions that drive thermoresponsive structural changes in the surrounding water molecules.

Abstract-Characterization of Dielectric Responses of Human Cancer Cells in the Terahertz Region

Keiichiro Shiraga, 

Yuichi Ogawa, 

Tetsuhito Suzuki, 

Naoshi Kondo, 

Akiyoshi Irisawa, 

Motoki Imamura

http://link.springer.com/article/10.1007%2Fs10762-014-0067-y
Terahertz time-domain attenuated total reflection spectroscopy, in combination with a two-interface model, is used to determine the complex dielectric constants of cultured human cancer cells (DLD-1, HEK293 and HeLa). Picosecond and sub-picosecond water dynamics are dominant in the measured complex dielectric constants of these cells. We demonstrate that dielectric responses below 1.0 THz best characterize the particular water dynamics of cancer cells when compared with extracellular water. Debye-Lorentz fitting revealed that this is due to a significantly attenuated slow relaxation mode and enhanced fast relaxation mode of the water in these cancer cells. These findings could lead to a new procedure to digitally evaluate cellular activities or functions, in terms of intracellular water dynamics, and remove the veil from the mysterious intracellular milieu.