Tokyo Metropolitan University
Recent publications
The x-ray spectroscopy of the muonic atom has attracted atomic, nuclear, and particle physicists since its discovery. The properties of a muonic atom, such as its binding energy or atomic radius, are different from an ordinary atom because of the difference in the mass between the muon and electron. Our collaboration has employed superconductor transition-edge sensor (TES) microcalorimeters for the x-ray spectroscopy of the muonic atom. Thanks to the recent detector development, the 44-keV lines from muonic Ar, which is important for the precision test of bound-state quantum electrodynamics, and the 76-keV lines from muonic Si, which is of interest from the viewpoint of the measurement of nuclear radii, have been reached by the dynamic range of the state-of-art TES microcalorimeters. An accelerator facility that can produce a high-intensity muon beam is necessary for such spectroscopic experiments. We performed a commissioning experiment of the hard x-ray and gamma-ray TES microcalorimeter at the J-PARC MLF MUSE muon beam line. The energy resolution, gain stability, and performance of timing selection of the pulses were evaluated in the environment of a large-scale accelerator facility.
Recycling of epoxy composites is of importance for achieving circular economy as demand for lightweight materials in the field of sustainable technologies is soaring. Although catalytic hydrogenolysis of epoxy resins provides a promising approach to recover valuable fillers and phenolic compounds from the composites, there is a lack of a reusable solid catalyst for this purpose. Here, we report a robust CeO2-supported Ni–Pd bimetallic catalyst (Ni–Pd/CeO2) for the hydrogenolysis of C–O bonds in epoxy resins under 1 atm of H2. Benefiting from its heterogeneous nature, Ni–Pd/CeO2 can be reused for several times. Furthermore, the catalyst is successfully applied to decomposition of epoxy composites to recover carbon or glass fibers and phenolic compounds, implying the potential application of our catalyst system toward recycling of epoxy composites.
Agricultural intensification has led to significant species losses and has been associated with a decline in ecosystem services provided by insects. In Asia, particularly in Lao PDR (Southeast Asia), biodiversity-friendly agricultural practices such as the production of organic crops have been promoted to address these challenges, although intensification has continued. In this study, we examined beetle community composition in three organic farms (using, for example, manure and compost and not employing synthetic fertilizers and pesticides) and three conventional farms (using, for example, synthetic fertilizers and insecticides) in Vientiane (Lao PDR). Our results indicate that total beetle abundance was similar between farm types, while species richness was greater, predators were over 18 times more abundant and insect pests were 9 times less abundant in organic compared to conventional farms. These findings can inform government organic farming policy in Lao PDR and the promotion of sustainable agriculture in Southeast Asia generally.
Atypical sensory responses and seeking behaviors constitute the core symptoms of autism spectrum condition (ASC). There are possible links between atypical sensory profiles and attentional challenges in ASC. Due to the paucity of studies in adults, the nature of attentional challenges and their associations with sensory profiles in autistic adults remain elusive. Here, we investigated sustained attention performance and its associations with sensory profiles in 28 autistic adult males and 23 typically developing controls (TDCs). A gradual-onset continuous performance task and the Adolescent/Adult Sensory Profile were employed to assess sustained attention performance and sensory profiles, respectively. Our results revealed that the two groups exhibited comparable sustained attention performance quantified by d-prime. A statistically significant negative correlation between d-prime and sensory seeking was observed only in the ASC group. Moreover, an interaction effect of group-by-sensory seeking was observed in d-prime, suggesting a unique interplay between sensory profiles and attention in autistic individuals. In the ASC group, omission error rate and post-error slowing were statistically significantly associated with difficulties in social communication and interactions. These results contribute to understanding attentional processes in ASC and highlight the potential influence of sensory profiles on cognitive functions in this population.
Background: Cerebral palsy (CP) often presents alongside cognitive developmental delays and motor impairments. This study aimed to identify the function most closely linked to the development of fluid intelligence in individuals with CP, and to estimate the point at which the fluid intelligence of children with CP diverges from that of typically developing (TD) children. Methods and procedures: Raven’s Coloured Progressive Matrices (RCPM) were used to evaluate the fluid intelligence of participants. Fifty-one participants with CP aged 4–18 years and 33 TD children aged 3–9 years were included in this study and underwent RCPM testing. The severity of CP was assessed using the Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS) and Communication Function Classification System (CFCS). Results: Multiple regression analysis demonstrated that within the three distinct functional levels, MACS was a significant predictor of fluid intelligence in children with CP (β = – 0.29, p < 0.05). Significant disparities in the development of fluid intelligence between the CP and TD groups emerge after 57.6 months of age. Conclusions and implications: The findings offer valuable insights into timely and functionally targeted interventions to prevent cognitive stagnation.
Mediation models are often conducted in psychology to understand mechanisms and processes of change. However, current best practices for handling missing data in mediation models are not always used by researchers. Missing data methods, such as full information maximum likelihood (FIML) and multiple imputation (MI), are best practice methods of handling missing data. However, FIML or MI are rarely used to handle missing data when testing mediation models, instead analyses used listwise deletion methods, the default in popular software. Compared to listwise deletion, the implementation of FIML or MI to handle missing data reduces parameter estimate bias, while maintaining the sample collected to maximise power and generalizability of results. In this tutorial, we review how to implement full‐information maximum likelihood and MI using best practice methods of testing the indirect effect. We demonstrate how to implement these methods using both R and JASP, which are both free, open‐source software programmes and provide online supplemental materials for these demonstrations. These methods are demonstrated using two example analyses, one using a cross‐sectional mediation model and one using a longitudinal mediation model examining how student‐athletes reported worry about COVID predicts their perceived stress, which in turn predicts satisfaction with life.
Iterative Learning Control (ILC) is a method to achieve tracking a specific reference by repeatedly updating control inputs. The learning algorithm of the ILC is conducted by using previous error information and learning parameters for systems that perform the same operation repeatedly. The ILC design requires an impulse response model for the learning coefficient matrix. However, it suffers from estimating an impulse response model in case where the measurement noise is present. Therefore, the study proposes a method for estimating impulse response to mitigate the influence of measurement noise. The proposed method estimates an impulse response projected to the linear space generated by the nominal model. The effectiveness of the proposed method is illustrated through numerical simulation results.
The switching frequency of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) should be increased to maximize their benefits in power conversion circuits. However, the switching loss increases when the switching frequency is increased. Generally, the gate resistance is designed to be small to reduce the switching loss for one cycle. However, SiC MOSFETs have a higher parasitic gate resistance than Si power devices. This paper proposes reducing the switching losses by “overdriving” the SiC MOSFETs, in which the gate voltage Vg is designed to be higher than the rated gate-source voltage of the SiC MOSFET. The relationship between gate voltage Vg and switching loss is clarified both theoretically and experimentally. Additionally, the effect of “overdrive” on the long-term reliability of SiC MOSFETs is evaluated by conducting continuous switching tests. The results show that “overdrive” can maximize the benefits of SiC MOSFETs based on the expected lifetime of the power conversion circuit.
The symbiotic nitrogen-fixing bacterium Bradyrhizobium japonicum (B.japonicum) enables high soybean yields with little or no nitrogen fertiliser. A two component regulatory system comprising FixL, a histidine kinase with O2-sensing activity, and FixJ, a response regulator, controls the expression of genes involved in nitrogen fixation, such as fixK and nifA. Only under anaerobic conditions, the monophosphate group is transferred from FixL to the N-terminal receiver domain of FixJ (FixJN), which eventually promote the association of the C-terminal effector domain (FixJC) to the promoter regions of the nitrogen-fixation-related genes. Structural biological analyses carried out so far for rhizobial FixJ molecules have proposed a solution structure for FixJ that differs from the crystal structures, in which the two domains are extended. To understand the FixJ activation caused by phosphorylation of the N-terminal domain, which presumably regulates through the interactions between FixJN and FixJC, here we have performed backbone and sidechain resonance assignments of the unphosphorylated state of B. japonicum FixJ.
Urban homelessness is a problem faced by both developed and developing countries due to various causes requiring contextualized responses. Governments have used temporary housing like shelter homes to combat homelessness, but providing adequate facilities and ensuring their use by the homeless remain significant challenges. This research article investigates the efficacy of shelter homes (locally known as Pannah Gahs) in Lahore. The objective is to explore the migration purposes of occupants contributing to urban homelessness, evaluate their satisfaction with shelter home facilities and understand their future migration intentions. Unstructured key informant interviews with Pannah Gah officials and semi-structured interviews of selected homeless people staying in the Panah Gahs were conducted. The finding reveals that, unlike in other developing countries, the government’s compassionate approach to treating homeless people with dignity, the security measures in place, and the staff training at Pannah Gahs have encouraged the homeless to use these facilities more frequently. However, most seemingly urban homeless people are economic migrants with homes elsewhere thus exhibiting a multilocality character. Employed homeless individuals often seek their own housing, while job-seeking homeless individuals tend to stay in their current situations due to financial constraints. The study highlights policy implications, advocating for a nuanced definition of homelessness considering economic migrants and spatially split households. It emphasizes the need for government support, such as affordable housing, and stresses that successful shelter home programs require government commitment, stakeholder collaboration, and comprehensive support services to restore the dignity and self-respect of the homeless.
A hexanuclear palladium cluster supported by two silylene units was readily linked by molecules of a linear ditopic isocyanide to afford a coordination polymer that retained the core Pd6(SiPh2)2Cl2 framework. The obtained coordination polymer exhibited good performance as a heterogeneous catalyst in the hydrogenation of various alkenes in common organic solvents and in protic solvents such as H2O. Furthermore, the obtained coordination polymer showed sufficient stability during the hydrogenation in order for it to be recycled and reused.
Brittle stars are marine invertebrates that often dominate the seafloor. Their global distribution and abundance make them useful as marine environmental bioindicators. Despite their importance, however, there is limited availability of data on brittle star specimens in Japan. In this study, we focused on Sagami Bay, one of the oldest Japanese marine areas for the study of brittle stars, and organized the data from the specimens collected there. This collection included specimens collected between 2005 and 2021, comprising a total of 695 samples, which were identified as 108 species. All data are deposited in the Global Biodiversity Information Facility (GBIF) through the Japan Node of GBIF and are thus accessible via the GBIF portal under the Creative Commons Attribution 4.0 International license. The Metadata for this abstract published in the Data Article section of the journal are available in MetaCat in JaLTER at https://jalter.diasjp.net/data/ERDP-2025-01 .
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1,467 members
Minoru Ijichi
  • Department of Biological Sciences
Tomokazu Numano
  • Department of Radiological Sciences
Yoshiaki Kikuchi
  • Department of Frontier Health Sciences
Noriaki Murakami
  • Department of Biological Sciences
Shinsuke Takagi
  • Department of Applied Chemistry
Information
Address
Tokyo, Japan
Head of institution
Takaya Ohashi, Doctor of Science