Toyama College

Abstract Ionizing radiation induces DNA damage both directly and indirectly through hydroxyl radicals (•OH) generated by water radiolysis. The indirect action involves hydrogen abstraction from deoxyribose, leading to DNA damage such as base release and strand breaks. The probability of such events depends on the accessibility of specific hydrogen atoms to OH radicals. Previous computational studies have examined naked DNA fragments; however, the effect of nucleosomal organization has not been addressed. Here, we performed molecular dynamics (MD) simulations using LAMMPS (Large-scale Atomic Molecular Massively Parallel Simulator) to evaluate the accessibility of •OH to deoxyribose hydrogens in both 12-bp naked B-type DNA and nucleosomal DNA containing histone proteins. The accessibility to the hydrogens increased, following the order H1’ ≈ H2’ ≈ H3’ < H4’ < H5’, consistent with previous studies. Accessibility was approximately proportional to the solvent accessible surface area (SASA), supporting SASA as a practical predictor of accessibility even in base-dependent differences were observed. In nucleosomal DNA, accessibility of hydrogens facing the histone core was significantly reduced compared to solvent-facing hydrogens, despite comparable SASA values. This reduction suggests that histones physically hinder OH radical penetration. These findings highlight the importance of considering protein–DNA complexes when modeling indirect radiation effects.

ABSTRACTAlterations in the immune system, stemming from sleep/wakefulness disorders, increase the risk of inflammatory pathologies. Orexin, a hypothalamic neuropeptide, regulates sleep and wakefulness. However, the role of orexin in inflammatory responses—whether it is protective or pathological—is still unclear. In this study, our aim was to elucidate the role of orexin in sleep and inflammatory states through the examination of a lipopolysaccharide (LPS)‐induced systemic inflammatory model and the effects of daridorexant, a dual orexin receptor antagonist. Intraperitoneal LPS administration significantly decreased rapid eye‐movement (REM) sleep and wakefulness while increasing non‐REM sleep. Pretreatment with daridorexant enhanced REM sleep recovery in LPS‐induced systemic inflammation, evidenced by extended duration and increased episode frequency. Transcriptomic profiling demonstrated a rise in the expression of pro‐inflammatory cytokines (Cxcl1, Ccl2, Ccl7, and Tnf) within the hypothalamus of LPS‐challenged mice, which was mitigated by daridorexant administration. In addition, daridorexant mitigated LPS‐induced acute lung inflammation. These findings suggest that by reducing pro‐inflammatory cytokine expression, the inhibition of orexin activity mitigates the lethargy associated with systemic inflammation, while also improving sleep quality. This study explores the potential of orexin receptor antagonists as strategic options for inflammatory pathologies and their associated sleep disorders.

The novel LpxC inhibitor T-1228 is a candidate drug molecule for multidrug-resistant Gram-negative bacterial infection. This report describes the synthesis of the diol unit of T-1228, (S)-1-(4-ethynylphenyl)ethane-1,2-diol, from commercially available 2-bromo-1-(4-iodophenyl)ethan-1-one, achieved in 5 steps and 4 isolations. The stereogenic center of the diol unit was created by means of a highly scalable form of the Corey–Bakshi–Shibata reduction; process parameters were optimized using the Design of Experiments methodology. Using this newly developed process chemistry route, we successfully synthesized 12.5 kg of (S)-1-(4-ethynylphenyl)ethane-1,2-diol in 60% total yield and optical purity >99% ee.

Indoor air quality (IAQ) meaningly influences human health and safety, particularly in enclosed environments. This work presents a machine learning (ML)-based framework for predicting air quality hazards and occupancy states using sensor-derived features, including gas concentrations (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{C O}_{\mathbf{2}}, \mathbf{C O}$</tex>, LPG), environmental parameters (temperature, humidity), and occupancy indicators (ultrasonic distance). Four supervised learning models-Random Forest, Logistic Regression, Gradient Boosting, and Decision Tree-were evaluated for their predictive performance on a dataset of 500 labeled samples collected from controlled experiments and real indoor environments. Amongst, Random Forest achieved the highest accuracy <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(56 \%)$</tex>, highlighting the ability of ensemble tree-based methods to capture intricate, non-linear relations in sensor data. The results also underscore the limitations of linear and singletree models when applied to small datasets with high variability. Overall, this study demonstrates that machine learning can provide predictive intelligence for indoor environments, supporting the development of real-time hazard monitoring and alert systems. Future work will explore temporal modeling, feature expansion, and real-time deployment to improve prediction accuracy and operational reliability.

In a wide range of industrial fields, the advancement of hydraulic dampers for vibration control has become an important research and development topic. In this paper, we propose a novel internal-flow origami hydraulic damper with nonlinear damping characteristics to overcome the limitations of conventional cylindrical hydraulic dampers with restricted linear strokes. First, the basic structure and design method of the proposed origami hydraulic damper are examined. Subsequently, the flow characteristics of the internal fluid in the origami hydraulic damper are analyzed, and a formula is derived to calculate the damping force acting on the damper. We confirm that the damping force is proportional to the square of the velocity. Furthermore, a verification experimental system using a nonlinear origami hydraulic damper in a mass-spring vibration system was developed. Shaking experiments using actual Fukushima earthquake waves were conducted, and the response acceleration decreased by 63.49%. For further verification, shaking experiments were performed by changing the orifice diameter of the nonlinear origami hydraulic damper, and the average reduction rate of the response acceleration for different orifice diameters was 62.68%. In addition, to verify the vibration control effect under different earthquake waves, we conducted shaking experiments using the same experimental setup and conditions as those used for the El Centro NS and Taft NW earthquake waves. The average reduction rate of the response acceleration for different earthquake waves was 62.22%. Thus, the damping characteristics and effectiveness of the proposed internal-flow origami hydraulic damper were confirmed.

In this study, a novel WPT coil for use in the 85 kHz band was developed. We proposed a hybrid coil that combines features of spiral coil and solenoid coil. This coil has both high k value of spiral coil and high self inductance of solenoid coil. Experimental verification based on simulation confirmed high transmission distance of 95% and long transmission distance of 170 mm.

Chất dính thủy tinh lỏng vẫn được sử dụng rộng rãi trong công nghệ đúc mẫu chảy để sản xuất các chi tiết có độ nhẵn bóng bề mặt cao, kích thước chính xác. Tuy nhiên, huyền phù thủy tinh lỏng vẫn còn một số hạn chế, thí dụ, độ thông khí kém, độ bền còn lại cao, dễ bị nứt bề mặt. Bài báo này giới thiệu một phương pháp biến tính thủy tinh lỏng nhằm khắc phục các nhược điểm trên. Chất biến tính nano-SiO₂ được tổng hợp bằng phương pháp sol-gel, với kích thước hạt trung bình là 20 nm. Các mẫu thử gồm nước thủy tinh lỏng được biến tính lần lượt bằng 2,5%, 5,0%, và 7,5% theo khối lượng, sau đó trộn từng mẫu với bột Zircon để đạt được tỉ lệ chất dính/bột là 60:40; 57,5:42,5; 55:45, chất phụ gia là Carboxymethyl cellulose. Các đặc tính của sơn khuôn mẫu chảy được đánh giá bao gồm độ nhớt, khả năng bám dính và độ thông khí. Thông số tối ưu đạt được là thủy tinh lỏng có mô-đun 2,9, được biến tính bởi 2,5% nano-SiO₂, sử dụng 0,5% chất phụ gia. Theo lý thuyết về đúc mẫu chảy, sản phẩm được đúc trong buồng chân không, sử dụng bơm để đạt được môi trường áp suất thấp. Trong nghiên cứu này, áp suất được áp dụng là 0,4 kg/cm² có thể cải thiện chất lượng vật đúc.

This work proposes a newly developed investigation robot operating in two modes: (1) autonomous and (2) manual mode. Designed to operate in hazardous environments such as confined, debris-filled, and dark spaces, the robot can autonomously navigate, collect critical data, and assess structural conditions. Upon completing its mission, the robot returns to its initial position, supporting the operator by improving operational efficiency and safety. The main implementation is the investigation of underfloor in Japanese houses. The robot navigates and updates its location on a predefined map. The robot recognizes possible cracks in the concrete blocks. Autonomy and remote control of the robot contribute to more efficient, timely, and safer underfloor investigation.