My research explores the mathematical connections between quantum mechanical scattering, nonlinear waves, and seismic waves to understand how mathematical methods and analysis can potentially gain new insights and develop novel approaches.
Finding and understanding the mathematical connections that exist between different fields and phenomena is what makes mathematical research so fascinating.

The field of my research is part of the qualitative theory of ordinary differential equations. In this research, we focus on the behavior of all solutions of nonautonomous ordinary differential equations. How does the variable coefficients of ODE influence the stability of the solutions? The main purpose of this research is to answer this question. In particular, we deal with the problem on the stability in the Lyapunov sense. For example, we treat asymptotic stability, uniform asymptotic stability and exponential stability. By understanding these essence, we aim to contribute to the development of ODE.

Salmon milt, defatted soybeans, crab and shrimp shells, and cowhide have been discarded as an industrial waste around the world. Therefore, DNA, soy protein, chitin/chitosan, and collagen, which are obtained from these materials, are sustainable resources. Our research using sustainable resources is as follows; 1) removal of harmful organic compounds; 2) selective accumulation of metal ion; 3) development of anhydrous proton conducting material; and 4) development of bioplastic with the biodegradable property.

On the basis of FIA and LC in analytical methods using a liquid flow as much as possible to concern for the environment, we have studied to develop separation materials using carbon microparticles, analytical reagents specifically reacting with organic compounds, separation and analytical methods of dissolved organic compounds and bacteria in natural waters, a nano-LC which can separate and analyze an analyte in a sample volume of 1/1000000000 liters using a liquid flow volume of 1/1000000 liters, and separation and analytical methods using a self-reaction of sugars and amino acids.

The kinds of polymers are relatively a few, which are used as plastics, rubber, and gels for daily life, since they exhibit versatile properties by hierarchical structure control ranging from nano- to micro-meter scales. In our laboratory, we focus to develop new polymeric materials by the hierarchical structure control and reveal the relationship between the mechanism and structure by microscope, scattering, and spectroscopy methods.

Hepatocyte growth factor (HGF) was originally identified as an hepatotrophic factor. During the past 30 years, we provided evidence to show that HGF plays an essential role for regeneration of several types of organs, including kidney, lung, hearts and neural tisses, using animal models of intractable disorders. HGF elicits unique biological activities, such as mitogen, motogen and morphgen via activating c-Met/HGF-receptor tyrosine kinase as shown below. Of note, a loss in HGF production is responsible for manifestation of acute and chronic organdiseases. This is the reason why HGF supplemental therapy produces benefit effects against the progression of acute and chronic organ diseases.

The final goal of our research is to converse with ants. Ants have long been thought to engage in detailed communication using chemical substances such as pheromones. However, our researchis revealing that acoustic signals are also important toos of communication.We conducte detailed analyses of organs such as “ears” and “sound-producing organs”. It will be able to control the behavior of ants like leaf-cutting ants, which are significant damage against human society.

We have been collaborating with various stakeholders such as the Fukuoka City, Fukuoka Prefecture, and the Ministry of the Environment to control invasive alien ant species such as the red imported fire ant, the yellow crazy ant, and Argentine ant. In Okayama Prefcture, there have been reported of the little fire ant (Wasmannia auropunctata) at Mizushima Port, and we will continue to control and manage these ants.

By using silk produced by silworms, which domesticated in China 6,000 years ago, and the silks spun by black Japanese weaver ant in Okinawa, we conduct research to create new fabric sheets. We hope that as this research progresses, the black Japanese weaver ant can be a symbolic relationship with humans as the fourth demesticated insect.

Primates (precisely non-human primates), are the animal group that shares the most similarities with humans. They show high levels of intelligence and social skills. Additionally, many primate species live in tropical and subtropical regions and are considered keystone species that play a fundamental role in maintaining tropical ecosystems. Researching the society and ecology of primates can provide us with valuable insights into the evolution and nature of humans. This knowledge can help us better understand ourselves, as well as contribute to the conservation of biodiversity and the resolution of global environmental issues. My work involves studying the society and ecology of primates and other large and medium-sized mammals, mainly through field observations. I also examine human society from a zoological perspective and its evolution. Currently, my team and I are conducting long-term field research and conservation activities to protect wild gorillas in the tropical forests of Central Africa. We also conduct educational and animal welbeing activities in zoos and perform behavior observation research on Japanese macaques in Japan.

We focus on the ecology of wild animals, including endangerd species, and their function in the ecosystem using direct observation or research tools such as camera trap. We explore better conservation methods and way for a sustainable coexistence with people.

Mammanlian reproductive status changes during postnatal development and aging. It can also be altered by environmental cues, stress or dysfunction of related organs. My research aims to clarify the factors and the mechanism which affect reproductive functions by using histological analysis on hypothalamic-pituitary-gonadal axis and measuring reproductive hormones. I am also working to establish methods to monitor reproductive status of wild animals by measuring steroid hormones in hair.

Japanese quail are the second most reared animal in the world poultry industry (meat and egg production), after chickens. Although suitable environments to improve productivity of domestic quail have been studied, not much is known about their biological characteristics, such as whether they are monogamous or polygamous, how females and males are involved in child rearing, and how they select partners. A better understanding of these issues will contribute to further improvement of quail productivity, and we are conducting behavioral and genetic research by actually raising and observing quail.
We also conduct population genetic and phylogeographic studies to understand how wild animals adapt to and live in their habitats, with focuses on wild animals.

The mechanical and electro-magnetic characteristics of metals are dependent on microstructures such as crystal orientation and grain diameter. In recent years, comprehensive studies have been carried out on thermo-mechanical control processing to improve physical properties of metallic materials without adding rare elements in order to save energy and resources. For example, high performance metals, such as ultrafine grain steel and magnetic steel, are developed by a combination of rolling and heat treatment. These metals exhibit uniform characteristics. However, it is more efficient if suitable characteristics can be generated at required positions. In our research, a new technology to control only material surface microstructure is being studied.

Study and practice on design methods of architecture in the context of urban space, public space, strategic urban regeneration by micro-intervention.
The main emphasis of my laboratory is to grasp architecture in the context of urban space and social situation, and use this for the basis for constructing both a new design theory and practical architectural projects.

The theme of our laboratory is to measure biological information obtained from humans and animals. Measured biological information is used in the development of various sensors, equipment, and software.

We have been working on the mechanism of inactivation of the plant hormone auxin. In one of our research projects, we have discovered potent plant growth regulator, designated as KAKEIMIDE, which is a potent inhibitor of the GH3 enzyme that inactivate auxin. Auxin degradation inhibitor in plants can regulate auxin levels in various plant species, including crops, and thus promote rooting of cuttings and fruit set and enlargement of fruits.

In our laboratory, we explore the untapped potential of microorganisms that play important roles in agriculture, food processing, and human health, both inside and outside our bodies. Our goal is to discover useful microorganisms with novel abilities and develop technologies to enrich our lives sustainably.

Through advanced imaging techniques, biochemistry, and gene expression analyses, I work to understand the mechanisms of how plants adapt to changes in the environment.

(1) Mechanisms of Plant Motion and Growth 　Many people believe that plants do not move. However, the reality is that plants respond by sensing changes in light intensity, color, and temperature and moving. I focus on the behavior of microtubules in plant cells, which may be playing a key role in regulating plant motion and growth. This project tries to answer this classic, unanswered question in plant physiology, one that had been a focus of Charles Robert Darwin (1809-1882), the Father of Evolution.

(2) Mechanisms of Plant Environmental Responses To adapt to environmental change, plants must survive and reproduce through seed production because they cannot physically leave the place where their seeds germinate. In particular, my focus is on how plants adapt to higher temperatures. As we face the challenge of climate change and global warming, understanding mechanisms of biological adaptation to higher temperatures is critical.

(3) Functions of Small RNAs on Plant Embryogenesis and Development Small RNAs play important roles to regulate plant embryogenesis and developments. I discovered a novel gene expression mechanism involving small RNAs. This project tries to further develop this new field in plant physiology.

I study hybridization and introgression of wild and cultivated plants using molecular markers. Especially I analyze those the distinction of which from native plants are now difficult due to their naturalizaion in pre-modern times. I also study the distinction and origin of cultivars using molecular genotying. In addition, I study the problems in denomination and nomenclature of cultivated plants as a member of the Internationl Commission for the Nomenclature of Cultivated Plants.

Infrorescence of a tree cultivated as ‘Somei-yoshino’ at the Koshikawa Botanical Gardens, University of Tokyo. I demonstrated that this individual has different genotype from true ‘Somei-yoshino’, the clonallity of the latter cultivar is verified by molecular markers.

Insects adapt to various terrestrial environments. In temperate regions, to survive cold temperatures in winter is essential for insects. Thus, many insects predict the arrival of period which is not suitable for development and reproduction, and change their physiological state. I am studying how insects regulate the life cycles in response to environmental signals, by field observations and rearing experiments.