Aqueous solutions of poly(N-isopropylacrylamide), P-NIPAAm, exhibit a noticeable temperature responsive change in molecular conformation at a cloud point temperature (T cp). As the temperature rises ...above T cp, the extended coil-like P-NIPAAm structure changes into a swollen globule-like conformation as hydration levels decrease and hydrophobic interactions increase. 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 elucidate 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 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 below T cp (≈10) 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.
Currently, various sake brewers employ data-driven approaches to ensure the stable production and supply of high-quality products. This study aimed to develop a novel direct measurement system using ...near-infrared (NIR) spectroscopy to monitor the fermentation process of sake mash during brewing. Direct measurement of sake mash has been challenging because of the significant absorption bands of water and the impact of physical properties such as multiple scattering within the mash. To address these challenges, we propose the subtraction of spectra, called differential reflectance, obtained through two measurement methods, namely, diffuse reflection and transflectance, to reduce the impact of physical properties. This approach includes limiting the wavelength range from 400 to 1300 nm, utilizing the second derivative in the Savitzky–Golay method, and applying multiplicative scatter correction (MSC) to the entire wavelength. When partial least squares regression (PLS-R) was applied, the root mean square error for predicting (RMSEP) alcohol concentration in the model sake mash sample (14.65–18.41 % v/v) was 0.33 % v/v. Finally, as a practical experiment, alcohol concentrations in the actual mash (0.00–17.49 % v/v) were predicted with differential reflectance spectra by MSC. The resulting RMSEP value was 0.76 % v/v, a significant improvement of 1.99 % v/v predicted by diffuse reflectance. These findings demonstrate the effectiveness of the proposed spectral subtraction method as a new direct measurement approach for monitoring sake fermentation in sake mash.
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•Direct ethanol measurement of sake mash without any sample preprocessing has been challenging by using NIR spectroscopy.•A measurement system combining the differential spectra method and multiple scattering correction was constructed.•Differential spectra could be used to quantify the ethanol concentration of sake mash without physical property effects.
Aceh is an important region for the production of high-quality Gayo arabica coffee in Indonesia. In this area, several coffee cherry processing methods are well implemented including the honey ...process (HP), wine process (WP), and natural process (NP). The most significant difference between the three coffee cherry processing methods is the fermentation process: HP is a process of pulped coffee bean fermentation, WP is coffee cherry fermentation, and NP is no fermentation. It is well known that the WP green coffee beans are better in quality and are sold at higher prices compared with the HP and NP green coffee beans. In this present study, we evaluated the utilization of fluorescence information to discriminate Gayo arabica green coffee beans from different cherry processing methods using portable fluorescence spectroscopy and chemometrics analysis. A total of 300 samples were used (
= 100 for HP, WP, and NP, respectively). Each sample consisted of three selected non-defective green coffee beans. Fluorescence spectral data from 348.5 nm to 866.5 nm were obtained by exciting the intact green coffee beans using a portable spectrometer equipped with four 365 nm LED lamps. The result showed that the fermented green coffee beans (HP and WP) were closely mapped and mostly clustered on the left side of PC1, with negative scores. The non-fermented (NP) green coffee beans were clustered mostly on the right of PC1 with positive scores. The results of the classification using partial least squares-discriminant analysis (PLS-DA), linear discriminant analysis (LDA), and principal component analysis-linear discriminant analysis (PCA-LDA) are acceptable, with an accuracy of more than 80% reported. The highest accuracy of prediction of 96.67% was obtained by using the PCA-LDA model. Our recent results show the potential application of portable fluorescence spectroscopy using LED lamps to classify and authenticate the Gayo arabica green coffee beans according to their different cherry processing methods. This innovative method is more affordable and could be easy to implement (in terms of both affordability and practicability) in the coffee industry in Indonesia.
Objective: Contact irreversible electroporation (IRE) is a method for ablating cells by applying electric pulses via surface electrodes in contact with a target tissue. To facilitate the application ...of the contact IRE to superficial lesion treatment, this study further extended the ablation depth, which had been limited to a 400-μm depth in our previous study, by using concentric electrodes. Methods: A prototype device of concentric electrodes was manufactured using a Teflon-coated copper wire inserted in a copper tube. The ablation area was experimentally determined using a tissue phantom comprising 3D cultured fibroblasts and compared with the electric field distribution obtained using numerical analyses. Results: Experiments showed that cells 540 μm from the surface of the tissue phantom were necrotized by the application of 150 pulses at 100 V. The outline of the ablation area agreed well with the contour line of 0.4 kV/cm acquired by the analyses. The ablation depth predicted for the concentric electrode using this critical electric field was 1.4 times deeper than that for the parallel electrode. For the actual application of treatment, a multiple-electrode device that bundles several pairs of concentric electrodes was developed, and confirmed that to be effective for treating wide areas with a single treatment. Conclusion: The electric field estimated by the analyses with the experimentally determined threshold confirmed that concentric electrodes could attain a deeper ablation than parallel electrodes. Significance: Using the concentric electrodes, we were able to localize ablation to specific target cells with much less damage to neighboring cells.
•Starch digestibility in fattening cattle can be estimated via fecal image analysis.•Three models were combined to estimate fecal starch content in fattening cattle.•High detection accuracy leads to ...estimating test data from an external farm.•The corn area is most important for estimating fecal starch content.
Estimating starch digestibility in cattle can be facilitated by examining starch content in their feces. Nonetheless, the chemical analysis of fecal starch content, which typically involves enzymatic reactions and colorimetry, is time-consuming and labor-intensive. In this study, we aimed to formulate a fecal image-based system to assess starch digestibility in fattening cattle. Images of the feces, including undigested corn particles, were taken with a smartphone’s color camera. The image dataset utilized in our experiments encompassed 4,570 images derived from 154 fecal samples obtained from six farms dedicated to fattening cattle. To assess the adaptability of our models, we conducted evaluations based on data from fecal samples originating from an external farm—one that was not included in the initial training set. Estimating fecal starch content involved utilizing three distinct models: EfficientNetV2, YOLOv8, and random forests. These models were built upon information about fecal water content, corn area, and the number of corns present. Subsequently, starch digestibility was derived from the estimated fecal starch content using an equation based on chemical analysis, as established in a previous study. Our proposed system exhibited an R2 and an RMSE of the estimated fecal starch content of 0.589 and 5.49% of dry matter, respectively. Furthermore, the RMSE of the estimated starch digestibility was 2.36%. These findings underscore the practicality of our starch digestibility estimation system when applied to fecal image analysis. This system holds promise in contributing to the real-time monitoring of the digestive system’s health status in individual farm animals.
Cells are the main component of our structures and functions, but the effective methods to examine the viability and activity of cultured cells in a non-invasive and unlabeled measurement haven't ...been fully developed. In this study, we demonstrated a completely new cell measuring technique based on an attenuated total reflection (ATR) spectroscopy in terahertz (THz) region, which is emerging with promising biological science. The cultured cell showed lower absorption than the medium between 1 and 13THz, and the decrease of the cell viability indicates a good correlation to the ATR signal.
Quantitative somatic cell count (SCC) measurement for detection of mastitis using an attenuated total reflectance (ATR) terahertz (THz) spectroscopy was investigated. Using samples with controlled ...SCC derived from raw milk, we measured their ATR signal in the THz region 30–440 cm−1 with a Fourier-Transform THz spectrometer. We found ATR signals decreased as SCC increased. Furthermore, we found the correlation between the ATR signal and SCC from 8.0 × 104 to 1.57 × 106 cells/mL was optimal at 139 cm−1 (R2 = 0.98). These findings demonstrate a potential to detect mastitis with a monochromatic THz wave.
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