Nagoya University · Physics and Astronomy
Professor Katsunori Yogo's research lab focuses on advanced materials and their applications in energy conversion, environmental remediation, and biomedical technologies. Key research directions include the development of zeolite-based catalysts for selective catalytic reduction of nitrogen oxides (NOx) to mitigate air pollution, and the design of functional nanomaterials—particularly gold nanoparticles—for enhancing radiation therapy in cancer treatment. The lab also investigates fundamental biological processes, such as DNA topology management by type-II topoisomerases, using single-molecule biophysics techniques. These interdisciplinary efforts bridge materials science, catalysis, radiation oncology, and molecular biology to address environmental and medical challenges.
Figures are computed from collected data and may differ slightly.
Abstract Selective reduction of nitric oxide with methane or ethane in the presence of excess oxygen was investigated using a gallium ion-exchanged ZSM-5 zeolite catalyst(Ga-ZSM-5). Ga-ZSM-5 was highly active and selective for NO reduction above 400 °C. The limiting molar ratios of reacted NO to consumed carbon in C2H6 and CH4 at 500 °C were found to be 1.5 and 2, respectively.
Abstract The reduction of NO with propane in the presence of excess oxygen was investigated using gallium ion-exchanged zeolite catalysts, among which ferrierite(Ga-ferrierite) and ZSM-5(Ga-ZSM-5) showed high activity in a wide range of reaction temperature.
Type-II DNA topoisomerases resolve DNA entanglements such as supercoils, knots and catenanes by passing one segment of DNA duplex through a transient enzyme-bridged double-stranded break in another segment. The ATP-dependent passage reaction has previously been demonstrated at the single-molecule level, showing apparent processivity at saturating ATP. Here we directly observed the strand passage by human topoisomerase IIα, after winding a pair of fluorescently stained DNA molecules with optical
Quality assurance (QA) of clinical electron beams is essential for performing accurate and safe radiation therapy. However, with advances in radiation therapy, QA has become increasingly labor-intensive and time-consuming. In this paper, we propose a tissue-equivalent plastic scintillator for quick and easy QA of clinical electron beams. The proposed tool comprises a plastic scintillator plate and a charge-coupled device camera that enable the scintillation light by electron beams to be recorded
+AuNPs at low concentrations displayed stronger radiosensitization compared to -AuNPs. Combining +AuNPs with 192Ir γ-rays in HDR brachytherapy is a candidate method for improving clinical outcomes. Future development of cancer cell-specific +AuNPs would allow their wider application for HDR brachytherapy.
Gold nanoparticles (AuNPs) can be used with megavolt (MV) X-rays to exert radiosensitization effects, as demonstrated in cell survival assays and mouse experiments. However, the detailed mechanisms are not clear; besides physical dose enhancement, several chemical and biological processes have been proposed. Reducing the AuNP concentration while achieving sufficient enhancement is necessary for the clinical application of AuNPs. Here, we used positively charged (+) AuNPs to determine the radiose
With advances in high-dose-rate (HDR) brachytherapy, the importance of quality assurance (QA) is increasing to ensure safe delivery of the treatment by measuring dose distribution and positioning the source with much closer intervals for highly active sources. However, conventional QA is time-consuming, involving the use of several different measurement tools. Here, we developed simple QA method for HDR brachytherapy based on the imaging of Cherenkov emission and evaluated its performance. Light
The accurate measurement of the 3D dose distribution of carbon-ion beams is essential for safe carbon-ion therapy. Although ionization chambers scanned in a water tank or air are conventionally used for this purpose, these measurement methods are time-consuming. We thus developed a rapid 3D dose-measurement tool that employs a silver-activated zinc sulfide (ZnS) scintillator with lower linear energy transfer (LET) dependence than gadolinium-based (Gd) scintillators; this tool enables the measure
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