Tokyo Denki University

Isoprene, a C5 hydrocarbon emitted by various land plants, serves as a protective molecule under heat stress. The moss Calohypnum plumiforme isoprene synthase (ISPS) catalyzes isoprene formation from dimethylallyl diphosphate and contains two aromatic residues (Y393 and F615) at the bottom of the active site that restrict the cavity size to accommodate the smaller C5 substrate. Here, we show that these residues are critical determinants of substrate size selectivity. Substitution of the two residues with alanine (Y393A and F615A) expanded the active site and exhibited diterpene synthase activity, generating ent-pimaradienes from ent-copalyl diphosphate. Further mutagenesis of the catalytic motif yielded ent-kaurene, demonstrating stepwise functional conversion from diterpene synthase to ISPS activity. Screening of ISPS genes across mosses identified two structurally unrelated enzyme classes: typical diterpene synthase-type ISPSs (C. plumiforme, Pohlia nutans) and microbial-type terpene synthase (TPS)-like ISPSs (Polytrichum commune, Leucobryum juniperoideum), the latter representing a previously unrecognized ISPS scaffold. Microbial-type TPS-like ISPSs of P. communehave two aromatic residues (W151 and F288), as in the case of C.plumiformeISPS, to restrict the cavity size. Substitution experiments expanding the active site in ISPS of P. commune (W151A and F288A) determined the production of ocimenes as monoterpene synthase activity. These results define the molecular basis of substrate specificity in TPSs and demonstrate that structurally divergent enzyme families can independently acquire ISPS activity.

We propose a method to transform the real world into a manga style in real time by adding onomatopoeia to real-world actions. In this study, we target clapping scenes, estimate onomatopoeia in real time from the clapping sound, and visualize them in the MR space. When we visualize onomatopoeia, we arrange them using a non-overlapping method to enhance visibility. Furthermore, we apply manga-style animations to the onomatopoeia to construct a highly immersive system. In an evaluation experiment on visibility, the proposed method received high ratings for manga style, sense of immersion, and visibility. In an animation evaluation, the proposed method received high ratings for sense of immersion and usability.

A ring light and a polarizing filter are attached to a smartphone to capture cross-polarized images of sublingual veins. This setup minimizes the glare caused by saliva and allows for clear visualization of deep sublingual veins, which have long served as notable diagnostic indicators in Traditional Chinese Medicine. In this study, quality of life is evaluated using the Chinese Medicine Quality of Life-11 Dimensions Assessment scale, and deep learning is applied based on the ResNet50 architecture. Once trained, the neural network can predict quality of life from new sublingual vein images.

Spherical particles that are neutrally buoyant in a square-duct flow are known to undergo cross-sectional motion due to inertial lift forces while being transported downstream. Far downstream, this lateral migration converges, and particles focus near the midpoints of the duct walls, as demonstrated by experiments, numerical simulations, and theoretical analyses. In contrast, numerical studies have predicted that relatively large particles at low Reynolds numbers can focus not near the wall midpoints but rather near the duct corners along the diagonals. In this study, we reproduce this diagonal focusing pattern numerically and confirm its occurrence experimentally. Numerical computations of the lift forces acting on a particle reveal the equilibrium points that appear within the cross-section and clarify their stability. Front-view observation experiments are conducted under corresponding parameter conditions, and the distributions of particle positions in the downstream cross-section are measured. Both numerical and experimental results confirm that particles indeed focus near the corners along the diagonals for specific parameter ranges. Furthermore, we show that this diagonal pattern transitions, with increasing Reynolds number, to a bistable focusing pattern in which focusing occurs on both the diagonals and the midlines, and finally to the standard midline-focused pattern. This sequence of transitions is explained by changes in the stability of the particle equilibrium points.

To enable natural non-verbal communication during immersive avatar control, it is essential to accurately reproduce an operator’s intended facial expressions on an android avatar. This study proposes a facial synchronization system that converts facial parameters captured from head-mounted displays (HMDs), into the corresponding expressions on an android avatar. In conventional systems, actuator commands controlling facial movements are typically mapped linearly to facial parameters. However, the correspondence between android facial actions and facial parameters cannot be clearly defined. We developed a motor command mapping model (the "developer model") that generates the developer’s intended avatar expressions based on facial parameter data and actuator commands collected through repeated facial mimicry. We then proposed and evaluated a "personalized model," which adapts the developer model to individual operators to better replicate their intended expressions. In a participant experiment comparing three models (conventional, developer, and personalized), no significant differences were observed. However, the developer model—despite lacking personalization—received evaluations comparable to the conventional model, supporting the effectiveness of the proposed approach. In contrast, the personalized model received mixed evaluations, with many participants rating it lower than the other two models, indicating a need to improve the personalization process. This study offers insights for developing more effective facial synchronization systems for immersive android avatars.

This paper presents performance comparisons among three bearingless motor topologies of homopolar, consequent-pole, and multi-monopole bearingless motors. These topologies have a two-pole suspension winding to generate a radial suspension force. The number of poles of the suspension winding does not depend on the number of rotor poles, and the suspension force can be controlled without rotor rotational angular positions. Representative bearingless motor performances are compared using three-dimensional finite element analysis, including the drive torques, suspension forces, and force error angles. The stator has an irregular distribution of stator slots to reduce the force error angle. Additionally, the stator has a combined winding that integrates the motor and the suspension winding. The results verify that the multi-monopole bearingless motor has high torque density with good force density.

Swarm robot systems perform long-term tasks such as information gathering and cooperative exploration while adapting to dynamic and unpredictable environments. These systems are increasingly applied in real-world scenarios such as lunar exploration and disaster response, where multiple robots operate independently and cooperatively across large areas. To support such missions, swarm robots often construct wireless communication networks spanning their deployment regions. Conventionally, the robustness of these systems has been evaluated mainly in terms of accidental robot failures, relying on redundant inter-robot connectivity. However, real-world environments also introduce spatially correlated failures, triggered by environmental phenomena such as flooding or structural collapse. To capture these effects, this chapter introduces a percolation theory–based framework for analyzing the robustness of communication networks formed by mobile robots with wireless relay capabilities. The proposed model incorporates two-dimensional noise fields to simulate environmentally induced failures and compares network robustness under environmental and accidental failure conditions. The results highlight distinct failure dynamics and identify redundancy strategies that can enhance overall system resilience. Furthermore, we establish how the spatial deployment and density of robots influence Quality of Service (QoS) indicators such as reliability and connectivity. Experimental results demonstrate that maintaining QoS under environmentally correlated (noise-induced) and accidental failures requires different redundancy strategies. These findings provide valuable insights for designing resilient 6G, Internet of Things (IoT), and disaster-recovery communication networks capable of operating in dynamic environments.

GRODMIC (GROup Delay between MICrophones) is a method proposed as a high spatial resolution source direction estimation for two microphones. Since a spatial aliasing is not required to consider for its applying, spatial resolution can be improved by extending the microphone width. In this method, the propagation delay characteristics between microphones are estimated by an approximation model, and the TDOA (Time-Difference-Of-Arrival) is estimated from the group delay characteristics. Therefore, the accuracy of group delay characteristics is important. However, multiple ripples tend to occur in the estimated group delay characteristics due to the high order model together with increasing of the wide width microphone pair. Due to this degradation of estimation accuracy, the advantage of high spatial resolution is lost. As a result, high direction estimation performance is limited to a situation to be able to apply a low order model. In this study, a reduction method of model order is proposed based on the approximation model characteristics.

This study analyzes the impact of spatial configuration in special nursing homes on caregivers’ burden and residents’ quality of life (QOL). Data were collected from 46 facilities in Tokyo and Tochigi before COVID-19, classifying configurations by the proportion of rooms facing common areas and the number of common spaces. Results indicate that the hall-type, integrated layout—often presented as a standard model for unit care—yields lower QOL ratings. In contrast, corridor-type and mixed-type layouts with a higher proportion of corridor-facing rooms, as well as segmented common spaces, prove advantageous.