Discrimination of male-sterility and male-fertility in Japanese cedar (Cryptomeria japonica) using near-infrared diffuse transmission spectroscopy.

The increasing demand for pollen-free seedlings of Japanese cedar (Cryptomeria japonica) has created a need for a simple method to discriminate between male-sterile and male-fertile strobili. The objective of this study was to establish a classification model to quickly and easily distinguish male-sterile and male-fertile strobili in C. japonica using near-infrared (NIR) diffuse transmission spectroscopy. The absorbance spectra of C. japonica were obtained for three different months from December 2022 to February 2023 and preprocessed using three methods: untreated, smoothing, and second derivative. Principal component analysis was applied to the NIR spectra and classification models were built using a support vector machine. The sample collected in January 2023 showed the highest discrimination accuracy of 89.38% with the smoothing preprocessing, which was improved to 89.97% by limiting the wavelengths to the NIR region. Furthermore, discrimination accuracy for independent test data was evaluated by splitting the data into training and testing sets using January 2023 data with smoothing preprocessing. The discrimination accuracy for test data sets was more than 85%, and the misclassification ratio was less than 20% for each sample group. These results indicate the potential of using NIR diffuse transmission spectroscopy to discriminate between male-sterility and fertility in C. japonica.

Characterization of time-series fluorescence properties of bean sprouts during storage using excitation emission matrix and fluorescence imaging.

Soybean (Glycine max (L.) Merr.) and mung bean (Vigna radiata L.) are popular varieties of bean sprouts, which are used in various Asian cuisines. The freshness of bean sprouts reduces at fast rate during storage. Hence, determining index of monitoring the state of sprouts is required to prevent unnecessary food loss, which is also linked to economical loss. The aim of this study is to reveal fluorescence characteristic of bean sprouts and investigate its potentiality for tracking the freshness state of bean sprouts. The fluorescence spectroscopy and imaging were used. For fresh bean sprouts, the Excitation-Emission Matrix (EEM) showed two fluorescence regions: Excitation (Ex) 270-300 nm with Emission (Em) 300-400 nm and Ex 300-350 nm with Em 400-450 nm, which are suspected to be amino acids and vitamins, respectively. When browning process started, the new fluorescence region occurred at Ex 400-450 nm with Em 450-550 nm. Consistent with EEM, under 365 nm, bean sprouts initially had blue fluorescence emission, and later changed to green when they start spoiling. However, due to higher emission, 420 nm-excitation wavelength was preferable for detecting browning part. With these basic fluorescence information, further application on inspecting both physical change and chemical change of bean sprouts can be easily established.

Investigating the characteristics of fluorescence features on sweet peppers using UV light excitation.

Sweet peppers are popular worldwide due to their nutrition and taste. Conventional vegetable tracing methods have been trialed, but the application of such labels or tags can be laborious and expensive, making their commercial application impractical. What is needed is a label-free method that can identify features unique to each individual fruit. Our research team has noted that sweet peppers have unique textural fluorescence features when observed under UV light that could potentially be used as a label-free signature for identification of individual fruit as it travels through the postharvest supply chain. The objective of this research was to assess the feature of these sweet pepper features for identification purposes. The macroscopic and microscopic images were taken to characterize the fluorescence. The results indicate that all sweet peppers possess dot-like fluorescence features on their surface. Furthermore, it was observed that 93.60% of these features exhibited changes in fluorescence intensity within the cuticle layer during the growth of a pepper. These features on the macro-image are visible under 365 nm UV light, but challenging to be seen under white LEDs and to be classified from the fluorescence spectrum under 365 nm light. This research reported the fluorescence feature on the sweet pepper, which is invisible under white light. The results show that the uniqueness of fluorescent features on the surface of sweet peppers has the potential to become a traceability technology due to the presence of its unique physical modality.

Characterization of fluorescence properties of wounds on soybean seedlings during healing process using excitation emission matrix and fluorescence imaging.

To establish a simple and nondestructive method for measuring plant wound-healing ability, we characterized the fluorescence characteristics of wounds on hypocotyl of soybean seedlings during healing process. Wounds were manually created on the stem of soybean seedlings 7 days after sowing. The fluorescence time-series characteristics of the wounds were measured until 96 h after wounding using excitation emission matrix (EEM) and fluorescence images excited by wavelength of 365 nm. In the EEM of wounds, three main fluorescence peaks were observed, and the intensity decreased with time after wounding. The reddish color due to chlorophyll in fluorescence images also decreased with healing process. In addition, microscopic observation of the wounded tissue using a confocal laser microscope showed that the intensity of lignin or suberin like fluorescence increased with healing time, which might have blocked the excitation light. These results suggest that UV-excited fluorescence can be a new indicator of the healing ability of plant tissues.

Macroscopic and microscopic characterization of fluorescence properties of multiple sweet pepper cultivars (Capsicum annuum L.) using excitation-emission matrix and UV induced fluorescence imaging.

Sweet peppers are a popular vegetable with various surface colors, such as green, purple, red, or yellow. To characterize the unique fluorescence properties associated with a broad range of sweet peppers of various colors (14 varieties), a fluorescence spectrofluorometer and imaging were used. The results showed that all cultivars in the experiment had blue fluorescence emissions when excited with light in the UV-A region, while chlorophyll fluorescence could be observed in green peppers. The emitted blue fluorescence originated from the epidermis (cuticle layer). The color distribution of these sweet peppers in the a* and b* color space were compared to the image obtained under white LED light. Yellow and red pepper cultivars have thicker, multiple cuticular wax layers and more distinct maturity stages than other sweet pepper varieties observed. With the establishment of this basic fluorescence database, further applications of fluorescence-based techniques and the unification of evaluation methods for pepper quality will be more easily established.

Antioxidant assessment of agricultural produce using fluorescence techniques: a review.

The study of bioactive compounds like food antioxidants is getting huge attention and curiosity by researchers and other relevant stakeholders (e.g., food and pharmaceutical industries) due to their health benefits. However, the currently available protocols to estimate the antioxidant activity of foods are time-consuming, destructive, require complex procedures for sample preparation, need technical persons, and not possible for real-time application, which are very important for large-scale or industrial applications. On the other hand, fluorescence spectroscopy and imaging techniques are relatively new, fast, mostly nondestructive, and possible to apply real-time to detect the antioxidants of foods. However, there is no review article on fluorescence techniques for estimating antioxidants in agricultural produces. Therefore, the present review comprehensively summarizes the overview of fluorescence phenomena, techniques (i.e., spectroscopy and computer vision), and their potential to monitor antioxidants in fruits and vegetables. Finally, opportunities and challenges of fluorescence techniques are described toward developing next-generation protocols for antioxidants measurement. Fluorescence techniques (both spectroscopy and imaging) are simpler and faster than available traditional methods of antioxidants measurement. Moreover, the fluorescence imaging technique has the potential to apply in real-time antioxidant identification in agricultural produce such as fruits and vegetables. Therefore, this technique might be used as a next-generation protocol for qualitative and quantitative antioxidants measurement after improvements like new material technologies for sensor (detector) and light sources for higher sensitivity and reduce the cost of implementing real-world applications.

Japanese dace (Tribolodon hakonensis) fish freshness estimation using front-face fluorescence spectroscopy coupled with chemometric analysis.

Although fish and its related products are good sources of protein and unsaturated fatty acids, like omega-3 in the human diet, their shelf-life is limited by biochemical and microbial changes. In this study, a front-face fluorescence spectroscopy technique was used to acquire Excitation-emission matrices (EEM) to monitor Japanese dace (Tribolodon hakonensis) fish freshness degradation during storage. EEM of Japanese dace fish parts (intact eyeball and surface-containing scales), excitation from 220 to 585 nm and emissions from 250 to 600 nm, were measured at different times during storage. To simplify the acquired complex spectra datasets from each fish part, the variables were reduced to those that were only significant/important (those with higher positive or negative correlation) for K value prediction, and as an index of freshness. Partial least square regression (PLSR) results demonstrated that combining the fluorescence EEM of the eyeball and surface-containing scales the best monitoring of fish freshness; excitation at 280 and 350 nm for both the eyeball and surface-containing scales, with 2.84 and 0.96 as RMSE and R2, respectively. These findings demonstrate that multiple excitation fluorescence approaches can be convenient for the freshness evaluation of fish.

UV excited fluorescence image-based non-destructive method for early detection of strawberry (Fragaria × ananassa) spoilage.

The soon spoiled strawberries need to be classified from healthy fruits in an early stage. In this research, a machine vision system is proposed for inspecting the quality of strawberries using ultraviolet (UV) light based on the excitation-emission matrix (EEM) results. Among the 100 fruits which were harvested and stored under 10 °C condition for 7 days, 7 fruits were confirmed to be spoiled by using a firmness meter. The EEM results show the fluorescence compound contributes to a whitish surface on the spoiled fruits. Based on the EEM results, UV fluorescence images from the bottom view of strawberries were used to classify the spoiled fruits and healthy fruits within 1 day after harvest. These results demonstrate the UV fluorescence imaging can be a fast, non-destructive, and low-cost method for inspecting the soon spoiled fruits. The proposed index related to the spoiling time can be a new indicator for qualifying strawberry.

Prediction of protein and oil contents in soybeans using fluorescence excitation emission matrix.

To investigate the potential of fluorescence spectroscopy in evaluating soybean protein and oil content, excitation emission matrix (EEM) was measured on 34 samples of soybean flours using a front-face measurement, and the accuracy of the protein and oil content prediction was evaluated. The EEM showed four main peaks at excitation/emission (Ex/Em) wavelengths of 230/335, 285/335, 365/475, and 435/495 nm. Furthermore, second derivative synchronous fluorescence (SDSF) spectra were extracted from the EEMs, and partial least square regression and support vector machine models were developed on each of the EEMs and SDSF spectra. The R2 values reached 0.86 and 0.74 for protein and oil, respectively. From the loading spectra, fluorescence at Ex/Em of 230-285/335 nm and 350/500 nm mainly contribute to the protein and oil content prediction, respectively. Those results revealed the potential of fluorescence spectroscopy as a tool for a rapid prediction of soybean protein and oil content.

Effect of Dy substitution in the giant magnetocaloric properties of HoB2.

Recently, a massive magnetocaloric effect near the liquefaction temperature of hydrogen has been reported in the ferromagnetic material HoB2. Here we investigate the effects of Dy substitution in the magnetocaloric properties of Ho1-x Dy x B2 alloys (x = 0, 0.3, 0.5, 0.7, 1.0). We find that the Curie temperature (T C) gradually increases upon Dy substitution, while the magnitude of the magnetic entropy change |ΔS M| and adiabatic temperature change ΔT ad showed a gradual decrease. On the other hand, due to the presence of successive transitions in these alloys, the peak height of the above magnetocaloric properties tends to be kept in a wide temperature range, leading to a relatively robust figure of merit in a wide temperature span. These alloys could be interesting candidates for magnetic refrigeration in the temperature range of 10-60 K.

Pressure-induced superconductivity in SnSb2Te4.

Here we firstly report the pressure-induced superconductivity in phase change materials SnSb2Te4. Single crystals of SnSb2Te4 were grown using a conventional melting-down method. The resistance under pressure was measured using an originally designed diamond anvil cell with boron-doped diamond electrodes. The temperature dependence of the resistance under different pressures has been measured up to 32.6 GPa. The superconducting transition of SnSb2Te4 appeared at 2.1 K ([Formula: see text]) under 8.1 GPa, which was further increased with applied pressure to a maximum onset transition temperature 7.4 K under 32.6 GPa.

Crystal Growth, Structural Analysis, and Pressure-Induced Superconductivity in a AgIn5Se8 Single Crystal Explored by a Data-Driven Approach.

A high-throughput first-principles calculation-assisted data-driven approach based on an inorganic materials database named AtomWork was performed to explore new superconducting materials. Specific band structures of a small band gap and flat band at band edges were used in a screening procedure. Among the candidates studied, we focused on AgIn5Se8, which shows a high density of state at the Fermi level. Single crystals of AgIn5Se8 were successfully obtained via a melt and slow cooling method. The valence states in AgIn5Se8 were estimated to be Ag1+, In3+, and Se2- using X-ray photoelectron spectroscopy. An electrical transport property of resistance was measured under high pressure using an electrodes-inserted diamond anvil cell. The sample exhibited an insulator-to-metal transition with a drastic decrease of the resistance by increasing the pressure up to 24.8 GPa. A possibility of a pressure-driven phase transition below this pressure was indicated by an enthalpy calculation. At a higher pressure region of 52.5 GPa, a pressure-induced superconducting transition was observed at 3.4 K. The maximum transition temperature was increased up to 3.7 K under the pressure of 74.0 GPa.

Rapid evaluation of quality deterioration and freshness of beef during low temperature storage using three-dimensional fluorescence spectroscopy.

We investigated three-dimensional (3-D) fluorescence spectroscopy for its potential to evaluate beef quality deteriorative changes and freshness. The fluorescence characteristics of heme, conjugated Schiff base and amino acids, could be indicators of internal biochemical reactions associated with beef deterioration, including color changes, lipid oxidation, and protein degradation, as well as a measure of freshness decline. To classify beef quality in terms of color (sensory index) and pH (chemical index), cluster analysis method (CA) was used. Three classes were identified: "fresh", "acceptable", "spoiled". We then developed a qualitative model to classify stored beef into these three classes using 3-D front-face excitation-emission matrices (EEMs) of fat tissue, combined with a parallel factor analysis (PARAFAC) algorithm. The resulting model had calibration and validation accuracies of 95.56% and 93.33%, respectively. These results demonstrate the potential of fluorescence spectroscopy to accurately and non-destructively monitor beef quality decline.

[Study of indoleamine 2,3-dioxygenase expression in patients with breast cancer].

We evaluated the clinical significance of indoleamine 2,3-dioxygenase (IDO) in breast cancer. Operative specimens obtained from 30 patients with breast cancer were investigated by semiquantitative RT-PCR with specific primers against IDO. The correlations among IDO expression, clinicopathologic factors and prognosis were studied. The expression of IDO was observed in 100%, both of the cancer specimens and the non-cancer specimens. The IDO expression of the cancer specimens was higher than the non-cancer specimens. The expression of IDO did not correlate to histologic classification, tumor size, lymphatic invasion, venous invasion and lymph nodes metastasis, but correlated to clinical stage and the serum level of immunosuppressive acidic protein (IAP). There were no correlations for a survival rate after surgery between the high IDO level group and the one. The serum IDO levels of cancer patients were higher than that of a healthy volunteer measured by semiquantitative RT-PCR and HPLC. It is suggested that the expression of IDO in breast cancer patients may play a critical role for immunosuppression in those patients.