Kitami Institute of Technology

Sub-terahertz astronomy requires instruments capable of simultaneous observations across multiple spectral bands, motivating the development of broadband anti-reflection coatings (ARCs). We investigated low-loss dielectrics with refractive indices suitable for multilayer ARCs on polyethylene optical elements and identified candidates that partially meet the requirements. To address the remaining gaps in available refractive indices, we applied dielectric multilayer synthesis by combining newly identified thin materials with controlled bonding to realize the required effective refractive indices. As a result, the fabricated five-layer ARC achieved reflection losses of 0.2% (average) and 3.2% (maximum) over 130-710GHz.

Hypochlorous acid (HClO) is widely used as a low-cost and effective disinfectant; however, its instability under heat and light necessitates simple and reliable monitoring methods. Herein, we report a morphology-evolving thin-film colorimetric sensor that enables intuitive visual detection of HClO through simultaneous color and pattern transitions. The sensor integrates two polymer films with distinct charge-state response behaviors, patterned into X-shaped and circular geometries on a single substrate. Upon exposure to HClO, chlorine-induced modification of amide and amine groups alters the surface charge states, thereby switching the adsorption preference for anionic and cationic dyes. This mechanism results in a pronounced transformation from a blue X-shaped motif to a red circular pattern, enabling direct visual discrimination of HClO concentrations. Quantitative analysis of RGB values and diffuse-reflectance UV–vis spectra confirmed semi-quantitative detection in the sub-millimolar to low millimolar range. The sensor further demonstrated practical applicability by tracking photodecomposition of a commercial disinfectant. This work demonstrates pattern-coupled colorimetric sensing as a straightforward, user-friendly approach for HClO monitoring.

There is a lot of previous research on smart agriculture. In this research, crop rotation is studied in smart agriculture. In some previous research on crop rotation, the expected profit of finite periods is maximized considering the fluctuating crop price. The previous method cannot maximize the expected profit after the finite periods. In this research, the expected profit of infinite periods is maximized considering the fluctuating crop price. In this research, the crop rotation problem is modeled by Markov decision processes. The expected profit is maximized by value iteration algorithm in the proposed method. The effectiveness of the proposed method is shown by some computational examples. The expected profit of the proposed method is greater than that of the comparison target. In the results of the proposed method, the adaptive crop selections according to the fluctuating crop price are confirmed. The proposed method is expected to contribute to the automation of decision making in smart agriculture.

This study explored the responses of cotton fabrics functionalized with lactate-responsive and non-responsive polymers, focusing on color and pattern changes. Circular samples, conjugated with lactate-responsive polymers and stained with indigotrisulfonate, showed distinct color shifts from blue to colorless as lactate concentration increased. This effect was linked to dye release triggered by lactate binding to boronic acid groups in the polymer. In contrast, samples with non-responsive polymers displayed minimal color changes. RGB analysis of photographs revealed significant R-value shifts in lactate-responsive samples, suggesting potential for semi-quantitative lactate detection via simple measurements. Additionally, facial pattern samples visualized the lactate response, transforming a smiling face into a crying face with rising lactate levels. Similar results were observed with another anionic dye, Acid Red 18. These findings demonstrate the promise of designing wearable lactate sensors that enable easy, burden-free monitoring. • Novel colorimetric lactate sensor concept utilizing pattern changes on fabric. • Lactate-responsive fabrics change from colored to colorless. • Smiling face pattern shifts to crying face with lactate rise. • Boronic acid binding triggers dye desorption in fabrics.

The establishment of ligand field (LF) symmetry around lanthanoid (Ln(III)) centres is of paramount importance to understand factors that govern magnetization relaxation in singlemolecule magnets (SMMs). We investigated a luminescent mononuclear Dy(III) compound [Dy(BA)₄] (pip) (1), where pip is a piperidinium cation and BA is a benzoylacetonate ligand. The stoichiometric compound exhibits zero-field SMM characteristics, quantum tunneling of magnetization (QTM) dominates magnetization relaxation. In the diluted version of the compound (1@Y), the QTM is mitigated, Raman and Orbach processes are involved in the relaxation. The effective energy barrier (Ueff = 53.61 cm-1 ; HDC = 0 Oe) estimated for magnetization relaxation is comparable with the LF splitting (ΔE = 57.2 cm-1) between the ground and first excited Kramers doublets (KDs) determined from the 4 F9/2→ 6 H15/2 Dy(III)based transition recorded at 2.4 K. By analysing the emission spectrum of the isostructural Eu(III) analogue as spectroscopic probe for site symmetry, the LF symmetry around the Dy(III) centre is assigned as C₂ᵥ. The close proximity (178 cm-1) of the triplet state of the ligand and 4 F9/2 state of the Dy(III) facilitates back energy transfer, thereby rendering 1 emissive only at cryogenic temperatures. The predictive accuracy of the complete active space spin-orbit configuration interaction (CASOCI) method is benchmarked against the experimental emission profile. Overall, we propose a strategy to assign effective LF symmetry around Dy(III), establish magneto-optical correlations, and provide a comprehensive analysis of emission process of 1.

The aim of this study was to identify and validate clinically meaningful predictors of local treatment failure (LTF) after stereotactic radiotherapy (SRT) for brain metastases by integrating machine learning (ML)-based feature selection with generalized linear mixed-effects modeling (GLMM). The retrospective study included 211 brain metastases from 63 patients treated with SRT. Each lesion was investigated independently, considering the within-patient clustering. Random forest classifiers were trained using a 3-fold cross-validation repeated 100 times to assess predictive performance and feature importance. The predictors included age, lesion length, biological effective dose (BED), sex, post-SRT systemic therapy, Karnofsky Performance Status (KPS), type of primary tumor, and lesion location. Features with high importance were further evaluated using GLMM to determine statistical significance. Receiver operating characteristic (ROC) analysis was performed to determine optimal thresholds and diagnostic accuracy. The median duration of follow-up was 232 days, and 31 lesions (14.7%) developed LTF following SRT. The ML model achieved a mean area under the ROC curve (AUC) of 0.88 and an accuracy of 0.84. Variable importance rankings identified age, primary tumor, BED, length, and KPS. The GLMM confirmed associations of lower BED (odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.80-0.98; P = .023) and greater lesion length (OR = 1.16, 95% CI = 1.08-1.24; P < .001) with LTF. The ROC analysis identified BED ≤60.0 Gy (AUC = 0.72; sensitivity = 0.81; specificity = 0.71) and lesion length ≥19.3 mm (AUC = 0.78; sensitivity = 0.58; specificity = 0.88) as thresholds. Lesion length was the most robust predictor of LTF after SRT, with a length ≥19.3 mm indicating increased risk.

In this study, we evaluated three renewable-based microgrid configurations designed to strengthen energy security and long-term sustainability. Configuration 1 integrates a photovoltaic (PV) array and wind turbines (WT) with a battery energy storage system (BESS). Configuration 2 replaces BESS with a hydrogen energy storage system (HESS), offering extended storage capacity and improved energy availability. Configuration 3 combines BESS and HESS, leveraging the advantages of short-term and long-term storage to create a more resilient energy system. The objective function was formulated to minimize the total annual cost (TAC) while optimizing energy generation, storage efficiency, and overall system reliability. A robust and efficient transient search algorithm (TSA) was employed to determine the optimal capacity of the microgrid configurations. A comprehensive cost analysis revealed that configuration 1 was the most cost-effective. However, incorporating HESS in configuration 2 resulted in a 41.3% increase in cost due to the investment required for electrolyzers, storage tanks, and fuel cells. Configuration 3, which integrates battery and hydrogen storage, incurred an additional 3.2% cost compared to configuration 2 and 45.8% compared to configuration 1. Despite the higher cost, this hybrid system enhances energy resilience by efficiently balancing short-term and long-term storage solutions.

Four optically active dodecen-4-olides (1a-d) with carbon-carbon double bonds at different positions and their cyclopropanated derivatives (2a-d) were synthesized, and the odour characteristics of the racemic and optically active compounds were evaluated. Compounds 1a-d and 2a-d exhibited typical lactone-like nuances, characterized by strong top notes and oily middle notes. The position of the carbon-carbon double bond had a significant effect on the odour profile. All 1a-d compounds exhibited different odour characteristics: 1a showed fruity notes, 1b and 1c exhibited green and fruity notes, and 1d exhibited green and floral notes. Cyclopropanation substantially altered these characteristics. As a result, the odour characteristics of compounds 2, where the carbon-carbon double bonds were converted to cyclopropane rings, differed significantly from those of compounds 1. Conversion of the double bond in 1a to a cyclopropane ring changed the fruity note to green note, while cyclopropanation of 1b changed the green note to fruity. The antimicrobial activities of 1 and 2 against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were also investigated. Only compound (S)-1b exhibited antimicrobial activity against S. aureus.