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.

I’m working on migration behavior of elements in hydrosphere from a chemical view.

【Elucidation of mechanism of solid-liquid interfacial reaction】
One of the factors affecting migration behavior of elements in environment (especially in hydrosphere) is “adsorption of dissolved species on soil”. In recent years, it has been reported that various reactions to the adsorbed species occur. I’m trying to elucidate the mechanism of the reaction.

【Elucidation of nature of dissolved species in hydrosphere】
The dissolved species in hydrosphere is complex because several dissolved species coexists. I’m trying to elucidate the nature of the complicated dissolved species with theoretical calculation.

In recent years, composite and polymeric materials have been increasingly replacing conventional metallic materials in aerospace, civil, marine, rail and automotive industries. Some applications of composite and polymeric materials involve dynamically loaded components and structures. Therefore, there is a need to fully understand the dynamic behavior of composite materials for the analysis and design of composite and polymeric structures subjected to impact loadings. However, the mechanical properties of composite and polymeric materials under dynamic loading conditions are not well understood, because there are no standard impact test techniques.
Consequently, we experimentally and numerically examine the effects of strain rate on the compressive and tensile characteristics of composite and polymeric materials. High strain-rate stress-strain curves are obtained on the standard or modified split Hopkinson pressure bar (SHPB). Low and intermediate strain-rate ones are measured in an Instron testing machine.

The engine is an essential piece of machinery that is used in vehicles, electricity generators, ships, and so on. However, fossil fuels are limited in their amount and engines exhaust carbon dioxide from the burning of hydrocarbon-based fuels, which is treated as a cause of global warming. Therefore, in order to deal with these problems, an alternative fuel is proposed that is comparable to fossil fuel in terms of fuel properties such as ignitability, calorific value, cold flow properties and oxidation, but which is environmentally friendly. In this laboratory, a study is conducted on the production and optimal usage of alternative fuels such as biofuel (e.g., biodiesel), gaseous fuel, and so on. Combustion technology for engine systems for low fuel consumption rate using natural gas and hydrogen is also studied.

In order to improve the performance of various industrial devices and to make effective use of energy, it is important to understand and control the mechanisms of momentum, heat, and mass transport by turbulent flows. Understanding of turbulent transport phenomena is also essential for accurate prediction of meteorological phenomena. Our specific research topics include: experiments and numerical simulations to elucidate the mixing mechanism of scalars in liquid-phase turbulent jets; measurements of momentum, heat, and mass transport across wind-wave air-water interfaces to improve the prediction accuracy of typhoons; experiments to elucidate the behavior of droplets and bubbles in turbulent flows; and the development of novel devices (plasma actuators) to reduce fluid friction drag.

In the case of metal materials are machined, the surface of materials are plastic defomed. Cristal structure of metal surface is strained by plastic deformation. The crystal structure strain changes the chemical property of surface. This phenomenon is called a mechano-chemical reaction. We study the mechano-chemical reaction and the relationship of machining process and material property.

We are investigating the dynamics of polycyclic aromatic hydrocarbons in the Seto Inland Sea and other areas of western Japan. In addition, clarifying the mechanism of contamination of Lake Kojima, we are conducting water quality surveys of Lake Kojima and elution experiments of organic matter and nutrient salts from the bottom sediment. We are also investigating the effects of chemical substances on the properties of aquatic organisms.

How can the population ｓustain in wetlands where the environment spatially and temporally fluctuates? We study the ecology of amphibians and reptiles in wetlands as target areas. Also, we study the anthropogenic impacts, such as paddy improvement and abandonment, on those populations from the viewpoint of conservation biology as well as ecology and evolution.

Bone histology is the study of bone function and growth by sectioning bones into thin slices to visualize internal tissues. This technique has proven instrumental in uncovering the physiology and ecology of extinct animals, providing insights into their growth rate, age, metabolism, and degree of aquatic adaptation — factors that were previously challenging to reconstruct. My research focuses on employing bone histology to explore the life and adaptive processes of large vertebrates, such as dinosaurs and mammals. Specifically, I aim to uncover what factors influenced these creatures to evolve into giants or diminutive forms and how terrestrial vertebrates altered their physiology and bone structure to successfully readapt to aquatic environments.

I have interests in parental care and sexual conflicts over reproduction in teleost fishes. My goal is to understand social relationship among individuals by approaching the field researches and observations in lab conditions, from evorutionary views. In the resent years, I also conduct some field works to examine a composition of food-webs in aquatic ecosystem and evaluate the relationships between biodiversity of aquatic animals (e.g. dragonflies) and their local and landscape habitats.

Now that Covid19 has settled down, the diversification of inbound customers will progress. Japan’s tourist areas will be required to be tourist areas that respond to diverse values such as religious diversity such as Halal, veganism, and LGBTQ. It means that each tourist area is required to select the value that is sought and to work on regional development that makes use of the strengths of the area.
Tourism has a broad base and a huge and growing market all over the world. In addition, it is an attractive industry that can realize tourism that benefits all people involved in tourism, including the industry, the business operators, and tourists.
I am interested in researching ways to help realize such a tourist area.

In response to the crisis of social, cultural, and economic sustainability in rural areas caused by declining birthrates and aging populations, the regional management movement, in which industry, academia, government, and the private sector collaborate to solve problems, has attracted attention.
In this laboratory, we support the construction of marketing databases for tourism marketing organizations that practice regional management, while analyzing the information obtained from these databases and examining effective regional management strategies.
There are two topics in this laboratory,
(1) Research on the relationships and roles among entities in effectively functioning regional management,
(2) Research on the construction of a marketing database that contributes to the formulation of regional management strategies and on evaluation indices for regional management.

We study on the biological characteristics of fish parasites with the aim of disease control. Also, many fish parasites in seafoods have been subject to complaints by comsumers. However, fish parasites normally live in wild environments, and it is crucial to discriminate between harmful and harmless for humans.
To improve the quality of farmed fishes, we try to feed grape pomace, effluent from winemaking, on the immunity and health condition in cultured fishes.

Despite being primarily developed for industrial purposes and not intended for direct human consumption, many chemical substances still come into contact with the human body and organisms in the environment through various pathways, such as water, air, and other environmental factors. Ensuring a safe and secure society requires a thorough evaluation of the toxicity of pharmaceuticals and chemical substances.
In our laboratory, we conduct research on the toxicity of chemical substances through comprehensive gene expression analysis and obtain omics data to elucidate the molecular-level mechanisms, a field known as toxicogenomics. In addition to utilizing omics technology for understanding the inter-organ coordination of energy metabolism in vivo, our research also focuses on elucidating pathological processes in both humans and dogs.

We mainly conduct research related to environmental health. We are working on microorganisms, viruses, contaminants, etc. that exist in water and soil. We also aim to search for useful microorganisms that can contribute to solving environmental problems. We also conduct research using epidemiological and informatic methods.

Two major research themes have been addressed. The first is the identification of novel pathogens and the development of disease control methods for fish and shellfish. In aquaculture farms, mortality caused by unidentified diseases is often observed. The causative factors are quite complex including deterioration of the environment, nutritional disorders, and outbreak of infectious diseases. With recent advances in aquaculture technology, the targeted species for aquaculture have expanded, and new infectious diseases have been reported one after another. Therefore, we are exploring the pathogens using a comprehensive genetics approach to develop the diagnosis methods and control the diseases. Second, we are also studying the unique immune system in shrimp. As invertebrates, shrimp have no adaptive immune system like vertebrates. However, they show some resistance to re-infection of particular pathogen, like a phenomenon known as “immunological memory”. We hope to elucidate the mechanism of this phenomenon and propose new disease control measures to improve productivity.

Veterinary pathology is the study of the causes of animal diseases and the study of their mechanisms. The results revealed by veterinary pathology are returned to clinical practice to help diagnose and treat animal diseases. Although our research targets all kinds of animals other than humans, we also contribute to the human medicine through basic research using laboratory animals.
I have experience in pathological diagnosis in a variety of animals, including companion animals, industrial animals, laboratory animals, wild animals, exotic animals, zoo and aquarium animals, fish, and invertebrates. I aim to identify issues from spontaneous diseases seen in various animals and to conduct research that can be fed back to clinical practice. At the same time, I will develop basic research using experimental pathological methods.

We not only analyze the health status of humans, animals, the environment, and food, but also develop new testing methods to evaluate them.
In recent years, we have been conducting joint research with local governments and companies to develop processing methods to reduce food loss and add value to food ingredients, to evaluate the pharmacokinetics of functional ingredients in foods, and to develop new testing methods for inflammation markers.