Hokkaido University Research Profiles

Japanese

"T" Researcher: 37

Numbers of lines 20 50 No Page Break Theme Icons
  • Life Sciences
  • Information and Communication
  • Nanotechnology / Materials
  • Manufacturing Technology
  • Human and Social Sciences
  • Energy
  • Environment
  • Tourism / Community development
  • Arctic Research
  • Social Infrastructure
  • Open Facilities
  • Cooperation and Value Creation in Community-based Workspaces

    Development process of coworking

    In recent years, working systems of individuals who do not necessarily have the same occupation or affiliation but interact and cooperate with each other according to the situation in organizations and local communities, as well as the workplaces that they share, have been attracting attention. This research is aimed to clarify the process of cooperation and value creation in such workplaces.

    Research

    The purpose of this study is to elucidate the process of cooperation and value creation in a community-type workspace. A community-type workspace is an open workspace where individuals share information and knowledge with other through communication, and create value through collaboration according to the situation. A coworking space is a typical example of such a place, and in recent years, it has been becoming more and more popular in Europe, the U.S., and the rest of the world. In the background, there is a movement of questioning the highly uniform interaction and cooperation among members in closed spaces, a system that is still dominant in organizations and local communities, and to achieve both individual autonomy and solidarity. This research is expected to provide knowledge that will contribute to the design and operation of such workspaces, as well as their organizational and social utilization, which are still largely unknown.

  • Environmentally Friendly Marine Biofouling Prevention Compounds Derived from Biomass

    Toxic marine anti-biofouling agents against barnacles and other marine organisms are causing pollution to the marine environment, and it is necessary to develop safe alternatives. We have succeeded in creating potent and low-toxicity compounds by synthesizing biomass-derived compounds. Further optimization is also possible.

    Research

    The use of the ocean by mankind (e.g., ships and cooling pipes for power plants) is essential, but marine fouling organisms such as barnacles impairs the fuel efficiency of ships and obstructs the functions, for example by clogging. Organotin compounds have been used to prevent functional impairment, but their use has been banned due to their toxicity, and the development of alternatives is desired. We are focusing on compounds used by marine organisms such as nudibranchs to protect against fouling by other organisms. As a result of synthesizing the compounds, we found functional groups (anti-fouling units) that are important for anti-fouling. The functional group was introduced into inexpensive biomass derived from marine organisms in a short process, and when the synthetic product was tested for anti-fouling (cypris larvae of striped barnacles), they were found to have both very strong anti-fouling activity and very weak toxicity. We are currently conducting research on the synthesis of similar compounds and the addition of further functions.

  • Community Development and Environmental Conservation through Interview Surveys

    Consensus building based on diversity

    Based on fieldwork in the Solomon Islands, Miyagi, and Hokkaido, we are studying the relationship between nature and local communities, and are conducting research on and implement the promotion of environmental conservation and community development from the bottom up. After the Great East Japan Earthquake, we have been conducting research in Ishinomaki City, Miyagi Prefecture, to support reconstruction efforts.

    Research

    We are conducting research to apply "interviews" to policies and activities. Local residents, researchers, and students collaborate to investigate people, nature, history, culture, and social issues in local communities, to identify issues, think of solutions, and consider the future of the region. We are practicing and applying the methods of interviewing and verbatim recording as tools for this purpose. We are researching the possibilities of qualitative research (interviews and verbatim recording) as a way of visualizing what cannot be seen in conventional quantitative research (statistics and questionnaires) and workshops, and to build relationships of trust.

  • Clarifying the Physical Constants of Electron Spin Control

    Accelerating the research and development of next-generation electronic devices

    Among various semiconductor properties, we have quantitatively clarified the previously unknown “spin-orbit interactions” of n-type quantum well structures based on InGaAs semiconductors, including gate voltage dependence. This achievement will be a seed for the development of next-generation spin devices.

    Research

    Existing semiconductor devices operate through the electric charge of electrons. In addition to the electric charge, an electron also has the other property of spin, which is a magnetic property. The electron spin in a solid can be aligned in a certain direction (Fig. 1a) or rotated about a specific axis (Fig. 1bc), depending on the situation. The key to realizing next-generation electronic devices is to control such electron spin in semiconductor devices. In this study, we used indium-, gallium-, and arsenic-based field-effect transistors (Fig. 2) and performed electrical measurements in a cryogenic environment (absolute temperature of 20 mK) using a dilution refrigerator (Fig. 3). In this way, we were able to precisely determine for the first time the spin-orbit interaction coefficient, which is necessary to control electron spin (Fig. 4).

  • Exploration of Marine Phytoplankton from Space

    Development of techniques for classification exploration and quantification of phytoplankton in the ocean using satellites

    We are developing a method to remotely survey floating microalgae (phytoplankton) in the ocean using earth observation satellites. We are currently examining a method to quantitatively observe the world’s largest number of taxonomic groups (11 groups) for remote sensing.

    Research

    Phytoplankton in the ocean is a primary producer that supports bioenergy production required for fish production, and the abundance ratios among different kinds of phytoplankton can be used as an indicator of different ecosystem structures (and thus different biological resources). It is expected that the application of satellite exploration technology will enable us to understand where, when, and how different ecosystem structures are fluctuating around the world, which will in turn enable efficient exploration, evaluation and management of biological and fishery resources.

    Takafumi Hirata Specially Appointed Associate Professor
  • Resilience and Adaptive Capacity of Arctic Marine Systems under a Changing Climate

    Overall understanding of marine ecosystems throughout the Arctic Rim

    International workshops have been held to present individual research results of existing research projects in the pan Arctic seas (i.e., the Arctic Ocean and adjacent subarctic seas), which have been underway in Japan, the U.S., and Norway, with the aim of achieving an overall understanding of the results in each area by identifying similarities and differences.

    Research

    The objective of this study is to provide an overall understanding of the response of marine ecosystems to environmental change in the Pacific-Arctic-Atlantic region by identifying similarities and differences in the circumpolar pan Arctic seas (i.e., the Arctic Ocean and adjacent subarctic seas). The Ecosystem Studies of Sub-Arctic and Arctic Seas (ESSAS), a regional research program of the Integrated Marine Biosphere Research (IMBeR), is the parent organization of this project. The research is promoted mainly by the scientific steering committee members from Japan, the United States, and Norway. Between 2015 and 2018, in particular, three international workshops were held to present the results of existing research in each country and to promote an integrated understanding of marine ecosystems throughout the pan Arctic seas.

    Takafumi Hirata Specially Appointed Associate Professor
  • Development of a Non-destructive CT-XRD Coupling Method and Its Application

    Visualization of the microstructure of hardened cement

    To develop innovative cement-hardening materials, we are devising a non-destructive integrated CT-XRD method, a novel measurement method combining the CT method to obtain geometric and spatial information on microstructures inside concrete with an accuracy of several microns, and a diffraction method to investigate hydrates and alterations in the region of interest.

    Research

    Concrete is structurally hardened by binding rock (aggregate) through a hydration reaction between cement and water. As a structural material, concrete is intended to withstand loading and certain weather/environmental conditions, but these may cause cracking of the concrete, which may progressively deteriorate due to strong acids and other chemical reactions caused by erosion and materials from the atmosphere, seawater and groundwater that come in contact with it. To stably use the social infrastructure for a long period of time, it is important to be able to see inside the internal structure of concrete with “bug eyes” and find any abnormalities that have occurred.
    With the pioneering “non-destructive integrated CT-XRD method,” the sample is irradiated with high-intensity X-rays from synchrotron radiation to selectively visualize 3D structures from transmitted monochromatic X-rays at 25 keV. Energy-dispersive X-ray diffraction is also performed in specific regions of interest through multiple slit operations to identify hydrates (portlandite, calcite, etc.), their alteration and aggregate minerals.

  • High-temperature Latent Heat Storage Microcapsules

    Core (alloy latent heat storage material) ? shell (Al2O3) type latent heat storage microcapsules capable of high-density heat storage in the high temperature range of over 500?C

    The latent heat storage method, which utilizes latent heat generated during the solid-liquid phase change, is attractive for its high-density heat storage capacity. Microencapsulation of latent heat storage material enables not only heat storage but also heat transport and heat control applications, and we have developed latent heat storage microcapsules that can be used in the high temperature range of over 500°C.

    Research

    An Al-base alloy with a melting point above 500°C was newly discovered as a latent heat storage material. By skillfully applying chemical conversion/oxidation treatment to the micro-particles of this alloy (approx. 20 μm or larger), we have succeeded in developing core (Al-base alloy) and shell (Al2O3) type latent heat storage microcapsules (Fig. 1). These microcapsules have high heat storage capacity of approximately five times that of solid sensible heat storage materials, and have excellent mechanical properties. Since the shell is made of Al2O3, it can also be treated as a ceramic particle. In other words, it is an epoch-making heat storage material of which the performance can be upgraded while maintaining the current use of ceramic sensible heat storage technology.

  • Multimedia Artificial Intelligence Technology Reaching Social Implementation

    Approaching the practical application of AI technology through industry-university collaborative research!

    With this research, we are developing artificial intelligence technology for multimedia data, mainly images, video, music, and audio. We are handling data related to medical images, social infrastructure data, materials science and other fields, mainly through industry-university collaborative research.

    Research

    We are not only conducting the world's most advanced artificial intelligence research, but also promoting research in interdisciplinary areas and taking on the challenge of solving real-world problems. Specifically, in medical imaging research, we have collaborated with many medical institutions in Japan to build AI technology that surpasses human diagnostic accuracy. In medical and civil engineering research, we have built Explainable AI (XAI), which not only enables learning of small amounts of data, a challenge in AI research, but also enables explanations of judgment results, making the technology usable in the real world. In recent years, we have also developed human-centric AI technology that can make decisions like humans by introducing information strongly related to human interests, such as human brain activity and eye gaze data, into the AI learning process.

  • Nonlinear Compensator That Can Be Implemented Without Sensors

    Nonlinear compensator that can easily be added to PID control systems

    Currently, PID control is used as the main control method in industry, but the PID control technique has a problem that the control accuracy deteriorates due to the influence of nonlinear terms such as friction and gravity. We have proposed a nonlinear compensator that can easily be added to PID controllers.

    Research

    Digital acceleration control (DAC) is a robust control technique for systems with nonlinear terms and modeling errors that are difficult to model. DAC is a very effective controller, but it cannot perform position control by itself because it controls the target acceleration value. Therefore, we have combined DAC with a general PID control system. This PID-DAC combined control system allows both robust position control and acceleration control. In addition, as a new nonlinear compensator that can easily be added to PID controllers without sensors, we propose two controllers: the PID-DA0 control system, which sets the target acceleration value of the control object to zero, and the PID-DJ0 control system, which sets the target acceleration value to zero. Both controllers can easily be added to existing PID controllers without additional sensors, so they have the great advantage of improving system performance sensorless.

  • Electrochemically Responsive Organic Dyes

    From electrochromism to multiple responses (fluorescence, circularity)

    Based on cationic organic dyes, which allow easy control of color tone, we offer a group of materials that can respond in multiple ways, including fluorescence and optical rotation (circular dichroism). This technology is designed to suppress the decomposition process of reduced species, and the bi-stability of oxidized and reduced species is such that exchange does not occur, even when they are mixed.

    Research

    Electrochromism is a general term for compounds that change their color tone in response to changes in external electrical potential. As materials that can undergo reversible color changes, they are attracting attention as light control materials for smart windows and display functions for electronic paper. Materials of which not only the color tone, but also fluorescence, optical rotation (circular dichroism), etc. can be changed, enable tailor-made responses according to the application.
    With this technology, we provide a group of substances with multiple responses based on cationic organic dyes of which the color tone can easily be controlled. The reduced species of cationic dyes are generally reactive, and the repeatability of the response is low, but with this technology, the decomposition process of the reduced species is suppressed by incorporating two cationic moieties. The bi-stability of the oxidized and reduced species, in which no exchanges occur, even when they are mixed, makes it possible to apply this technology to high-density recording materials.

  • A method to evaluate radio wave propagation characteristics of in-vehicle wireless access services by large-scale electromagnetic field analysis

    Toward optimal design of wireless environments

    We have conducted research in various fields where radio waves are applied, including the evaluation of complex and special propagation environments in airplanes and passenger railroad cars, internal exposure of the human body to radio waves, electromagnetic interference evaluation and mechanism estimation regarding body medical devices implanted in the body, and evaluation of electromagnetic field leakage in wireless power supply devices for electric vehicles.

    Research

    The radio propagation environment inside a vehicle is a special environment that differs from the conventional propagation model due to multiple reflections caused by the surrounding metal and the presence of fixtures and passengers inside. It is therefore necessary to evaluate the characteristics of radio wave propagation, including the effects of absorption and scattering of radio waves by the bodies of passengers, to estimate the quality of the wireless connection under actual operational conditions. However, it is difficult to evaluate the propagation characteristics by actual measurement or simple numerical analysis (e.g., ray tracing). This study addresses modeling of the propagation environment in vehicles, which has been difficult in the past, and realizes a simulation method in a very large analysis space by using a supercomputer.

  • Super-hierarchical Structure Imaging Through the Combined Use of Neutrons and X-rays

    Non-destructive imaging of unknown information over a wide range of scales using multi-quantum beams

    Pulsed neutron transmission spectroscopy imaging is attracting attention as a method of non-destructive visualization of information that cannot be seen with other microscopic methods, and when it is combined with other quantum beams such as X-rays, it is possible to visualize information that cannot be seen with images alone.

    Research

    Hokkaido University’s laboratory facilities, where small accelerators are used, have a history of nearly half a century, and are attracting worldwide attention as pioneering facilities. We mainly produce pulsed neutron beams, and the transmission spectra obtained using these beams enable us to map information on crystal structure, microstructure, internal stress and temperature on a two-dimensional real image as a distribution map of the entire sample. We also use X-ray CT which can measure the three-dimensional structure of the inside of an object, and analyze the combined results from neutrons and X-ray studies to synergistically understand the interior information of an object. In the figure, shown as synergistic imaging based on information from neutrons and X-rays, information on elements that cannot be individually obtained is mapped on the inside structure shown on the X-ray CT image. X-ray CT shows the presence of wires in an Al cylinder, but when neutron information is added, we can see that each wire is a different material.

  • Development of Reagents for Highly Efficient Transfection of siRNA into Immune Cells and Their Application to Cancer Immunotherapy

    Development of next-generation drug delivery systems

    We have developed a reagent (YSK12-MEND) to introduce siRNA into immune cells with high efficiency. If siRNA is introduced into immune cells using this reagent, the expression of immunosuppressive genes can be reduced with high efficiency, and thus it is expected to be applied to cancer immunotherapy using immune functions.

    Research

    We have developed YSK12-MEND, a reagent that can efficiently transfect siRNA, a gene expression inhibitor, into mouse and human immune cells. By using the novel reagent, the efficiency of siRNA transfection into mouse dendritic cells has improved more than 10-fold compared to the commercial product (Lipofectamine RNAiMAX). It is known that the function of immune cells is suppressed by cancer cells in cancer patients, although humans have an immune function to fight cancer cells. siRNA delivery using YSK12-MEND can efficiently suppress the expression of immunosuppressive genes in immune cells, which will enable humans to fight cancer cells with their own immune function. YSK12-MEND is expected to be one of the promising candidates for this purpose.

  • Applied Research on Content Tourism

    International comparative study on the propagation and acceptance of culture through content tourism and its application to the planning of tourism town planning measures

    We are conducting an international comparative study of content tourism from the perspective of the propagation and reception of pop culture to clarify the role that such tourism plays in understanding others. The knowledge gained through this research is also returned to the fields of tourism and urban planning in the form of specific measures.

    Research

    Through this research, we are conducting an international joint research project on content tourism (the act of actually visiting a place that is given meaning by a “story” or “work” and its constituent elements, and experiencing the relevant content) with the following three objectives:
    First, we will clarify the role that such tourism plays in understanding others by rethinking content tourism from the perspective of the propagation and receipt of pop culture. Secondly, based on this, we will consider how to create a model exchange-oriented tourism town with content at its core. Thirdly, we will focus on the East Asian region, where Japan's geopolitical situation calls for international mutual understanding, and consider the possibilities and challenges that content tourism, triggered by Japanese content, has for Japan's cultural security.

  • Gel that is Stronger Than Steel

    Soft and tough composite material

    By conjugating glass fiber and self-healing gel, we have achieved a gel that is stronger than carbon fiber-reinforced plastic (CFRP). Since the base material is a gel, it is as flexible as rubber against bending, but tougher than CFRP against tearing, making it difficult to break.

    Research

    The glass fiber composite gel we have developed exhibits unbreakable, untearable and tear-resistant properties. Generally speaking, CFRP and glass fiber reinforced plastic (GFRP) are widely used as composite materials. Similar to these fiber-reinforced plastics, fiber-reinforced gels are hard and resistant to tension because of the characteristics of the fibers, while being soft and flexible on bending because of the characteristics of the gel. The self-healing polyampholyte (PA) gel used as the base material is also strong as such thanks to its ability to dissipate a large amount of energy against deformation. Since the gel is flexible, when it is combined with fiber, local distortions can be transmitted through the fiber to the distant base material, resulting in large energy dissipation of the entire material, meaning that it is remarkably strong.

  • High Strength Gel That Spontaneously Bonds Strongly with Bone Tissue

    Development of a safe, high-strength bonding method between wet materials and bone, which has been difficult to achieve so far, by utilizing bone healing in living organisms

    In answer to the issue of in vivo fixation by applying the much anticipated high-strength hydrogel as a next-generation artificial cartilage or cartilage tissue regeneration scaffold material, we have developed a simple, non-toxic, high-strength adhesion method using hydroxyapatite, an inorganic component of bone tissue.

    Research

    The high-strength, high-toughness double-network gel (DN gel) previously developed by our group has excellent properties such as low wear on cartilage and induction of cartilage tissue regeneration in a natural joint, and is being studied for application as an artificial cartilage material and cartilage regeneration induction material. On the other hand, it is difficult to fix and maintain such a gel in a natural joint, which has been a major issue with the practical use of this material. In this study, we developed a fixation method that allows bone tissue regeneration to progress spontaneously into the gel and adhere firmly by compounding hydroxyapatite (HAp), the main inorganic component of bone tissue, to the surface layer of the DN gel. In addition to excellent mechanical properties and cartilage regeneration ability, the realization of non-toxic in vivo adhesion to bone is a great step forward toward the practical application of DN gel for joint treatment.

  • Communication-avoidant Matrix Calculation Algorithm

    Research and development of algorithms suitable for massively parallel computers

    With the spread of massively parallel computers, it has become increasingly important to reduce the communication time associated with parallel computation. In this research, we aim to improve the performance of matrix computation algorithms by using an approach called “Communication Avoiding (CAA).”

    Research

    With parallel processing using large-scale parallel computers, the data communication time is often more important than the computation time. In particular, the large communication latency (the cost incurred regardless of the amount of data to be communicated) has become a problem, and there is a strong need to reduce the communication frequency (communication avoidance). We are reviewing existing matrix computation algorithms from the viewpoint of communication avoidance, and are researching and developing new algorithms for massively parallel computers that reduce the communication frequency.

  • Hydrogenation with Homogeneous Palladium Nanoparticle Catalyst

    Selective synthesis of cis-alkenes and amines

    cis-Alkenes and amines, which are useful as raw materials for pharmaceuticals, agricultural chemicals and other chemical products, can be synthesized efficiently through hydrogenation of alkynes, organic nitro compounds and azides. The originally developed homogeneous palladium nanoparticles can be stored in solution for longer than a year and are easy to handle in air.

    Research

    We have found that homogeneous palladium nanoparticles can be obtained by treating palladium acetate with potassium tert-butoxide or sodium borohydride in the presence of alkynes (Fig.1). The nanoparticles can be stored in solution for longer than a year and are easy to handle in air. They exhibit excellent performance as hydrogenation catalysts and can efficiently synthesize cis-alkenes (2) and amines (4 and 6) from alkynes (1), organic azide compounds (3) and aromatic nitro compounds (5), respectively. They have excellent cis-alkene selectivity and functional group tolerance (no loss of the ketone, aldehyde, or benzylic hydroxy group, etc.). The catalytic activity is extremely high; the reaction proceeds quickly using only 1/1000 to 1/5000 equivalent of palladium of the substrate (raw material). It also has excellent economic efficiency and convenience, and we are examining the possibility of commercializing it in cooperation with companies.

  • Semiconductor Precision Processing Technology

    Low-damage and controllable semiconductor etching technology using electrochemical reactions

    A semiconductor etching technique using electrochemical reactions was developed to reduce damage and achieve precise processing control in the depth direction compared with conventional methods, and was applied to the gate recess processing of AlGaN/GaN heterostructure transistors to realize normally-off transistors.

    Research

    The etching process of semiconductor surfaces is one of the essential steps in the fabrication of semiconductor devices such as transistors. In this laboratory, we have developed an etching method that is superior to conventional dry etching methods in terms of both depth control and damage suppression, by utilizing electrochemical oxidation and dissolution reactions on semiconductor surfaces. As a result of applying the method to AlGaN/GaN heterostructures, which are considered to be promising power transistor materials, it was revealed that the etching process can be self-stopped at the desired processing depth by optimizing the electrochemical conditions, thus eliminating the need for an etching stop layer, which had been essential in prior technologies, and enabling precise control of the transistor threshold in a simpler way. In addition, the etched surface by this method has less processing damage than the dry-etched surface, and is expected to be a promising method for improving transistor performance.

  • Stabilization of Nanoparticles Using Cyclic Poly(ethylene Glycol)

    A novel stabilization method relying on the “topology” of polymers

    In this research, we developed a novel dispersion stabilization method for metal nanoparticles using cyclic poly(ethylene glycol). The research group has found that molecular aggregates consisting of cyclic polymers have excellent stability. By applying this phenomenon, the dispersion stability of nanoparticles can be enhanced.

    Research

    A large number of nanoparticle-based drugs are currently investigated, including drug delivery system (DDS) carriers, many of their surface is covered with biocompatible poly(ethylene glycol) (PEG). In this regard, we have found that gold nanoparticles (AuNPs) modified with cyclic PEG exhibit high dispersion stability at high salt concentrations. In other words, AuNPs treated with cyclic PEG with a molecular weight of 4000 retained their dispersion stability for one week or longer in a 180 mM NaCl solution, which is a higher concentration than physiological conditions, whereas AuNPs treated with linear PEG of the same molecular weight started aggregating and precipitating within 3 hours in a solution of only 45 mM NaCl. This novel method using cyclic PEG can be applied to a variety of nanoparticle-based drugs including contrast agents and magnetic nanoparticles.

  • Multi -beam Ultra-high Voltage Electron Microscope and Materials Research

    Multi-beam science and engineering applications

    At the High-Voltage Electron Microscope (HVEM) Laboratory of Hokkaido University, the world’s first multi -quantum beam HVEM has been developed. It enables in-situ observation of microstructural changes on an atomic scale using multi-quantum beam irradiation.

    Research

    The world’s first multi-quantum beam HVEM (left)
    In 2014, we added an optical system that allows the use of multiple lasers, and developed a multi-quantum beam HVEM that allows in-situ observation at the atomic level under irradiation by multi-quantum beams, including ion, laser and electron beams. We are currently developing an in-situ spectroscopy system.

    Nanocrystal growth by UV irradiation (right)
    We have succeeded in growing ZnO nanocrystals by irradiating submerged plasma-treated Zn with UV light. We are now promoting research on the growth mechanism and its application.
    Scientific Report, 5, 11429(2015), AIP Advances, 7(2017) pp. 035220, Other reference: Nano Letters, 17(2017) pp. 2088-2093

  • Rheumatoid AI Diagnostic Research

    Simple photographic assessment of joint space narrowing

    We will attempt to develop a consulting system that provides objective and detailed quantitative analysis information on destructive joint changes in rheumatoid arthritis patients. The image analysis will be measured based on changes in X-ray images over time using a program we had developed, and the information will be provided to research and clinical institutions in Japan and overseas.

    Research

    We have been developing and validating software to objectively measure the progression of joint space narrowing on plain x-rays. The latest software, using our original temporal subtraction and contour extraction techniques, is capable of displaying changes (in square millimeters) in the area of the joint space of the target limb.
    On the other hand, even from a global perspective, it is difficult to automatically detect the progression of joint space narrowing on plain x-rays using software, and the process still partially relies on manual operation, making it impossible to perform measurement at individual hospitals or clinics. Therefore, the purpose of this study is to establish an internet-based consulting system for quantitative analysis of destructive changes due to rheumatoid arthritis that can meet the needs of domestic and international clients who lead clinical trials and clinical research.

  • Development of Innovative Anodized Aluminum and Their Functions

    When the surface changes, everything changes.

    We will introduce our research on the development of superior properties and new functions of aluminum by innovation of anodizing, which is an extremely well-known corrosion-resistant passive coating for aluminum.

    Research

    Anodic oxide film is an artificial passive film formed on the surface of aluminum, and was developed in Japan about 100 years ago. There are many anodized aluminum products around us, but our research group is reviewing the chemical substances and formation methods (anodic oxidation) used to form anodized aluminum surfaces from the ground up, and we try to develop a new anodizing method that exhibits superior properties and innovative functions. Specifically, we are developing anodized aluminum with highly ordered nanostructures, hard anodized aluminum with a Vickers hardness of Hv = 600 or higher, anodized aluminum with high corrosion resistance in acid, base, and chloride environments, and anodized aluminum that shines beautifully by producing luminescence and structural colors.

  • Fabrication of High-speed Superhydrophilic Surfaces and Sliding-controlled Superhydrophobic and Superoleophobic Surfaces

    Both water and oil can soak well into the surface, slide off it easily, and stick to it properly

    We will show you how to create superhydrophilic surfaces that can rapidly be wetted and covered in water, and superhydrophobic and superoleophobic surfaces that repel water/oil very well although their sliding behavior can easily be controlled to allow water/oil to be adsorbed on the surface or easily slide off.

    Research

    Anodizing is a technique used to form oxides with various nanostructures on the surface of metals. We have developed a method to form a large amount of nanofiber oxides with a diameter of sub-10 nm (10 nm or less) by anodizing using a novel electrolyte chemical species. The density of nanofiber formation is extremely high, in the order of 1010 nanofibers (10 billion nanofibers) per cm2. We have found that the metal surface formed with such high-density nanofibers exhibits fast superhydrophilicity of one second or less, as well as superhydrophobicity and superoleophobicity with controlled sliding behavior. It is also possible to mix surfaces with different wettability by using micropatterning techniques.

  • Uncovering the relationships among air pollution (aerosols, PM2.5), wildfires, snow and ice, and climate change in the Arctic and cryosphere for a sustainable society in the future!

    An atmospheric scientist working in the Arctic and cryosphere, tackling wildfires, air quality, snow and ice, and climate change

    I am conducting a wide range of research on wildfires and their air quality (aerosols and PM2.5), including analysis and prediction of the factors that cause them and impact assessment (climate, health, economy, etc.), using various research methods from observation to data analysis and modeling.

    • Figure 1b from Yasunari et al. (2018, Sci. Rep.). Daily mean PM2.5 concentration on July 25, 2014, calculated using NASA's MERRA-2 reanalysis data. The white circle indicates the location of Sapporo City.

    • A commercial version of the PM2.5 measurement system for cold regions, updated from the prototype in Yasunari et al. (2022, J. Environ. Manage.). Anyone can purchase it from Tanaka Co., Ltd. (http://kktanaka.co.jp/products; the iron box and the low-cost PM2.5 sensor must be obtained separately)

    • A climate (atmospheric circulation) pattern that can likely cause co-occurrences of European heatwaves and wildfires in Siberia and subarctic North America (Alaska and Canada), as discovered in Yasunari et al. (2021, Environ. Res. Lett.): the pattern was named the circum-Arctic wave (CAW) pattern because it is a pattern in which anticyclonic circulation is arranged to surround the Arctic. The figure is from Figure 9 of the paper (created by the current “Science Manga Studio Co., Ltd.”: https://www.sciencemanga.jp/).

    • In Yasunari et al. (2024, Atmos. Sci. Lett.), the authors used the commercial PM2.5 measurement system for cold regions and, for the first time, performed the local ambient air quality observation (i.e., PM2.5 measurement) in Qaanaaq, northwest Greenland, in the summer of 2022. They also captured the worsened air quality during the local open waste burning (the figure is the Graphic Abstract of the paper).

    Research

    In recent years, we have been hearing more and more news about wildfires. Large-scale wildfires can transport air pollution (PM2.5) not only to the area where they occur but also to areas downwind, potentially affecting the people who live there. For this reason, it is necessary to identify the causes of wildfires and the atmospheric aerosols (air pollution) they produce and assess the diverse effects (such as climate, health, social and economic) that follow. In addition, it is extremely important to predict these effects based on the knowledge gained from the perspective of taking measures for people living in the downwind area from where the fires occur. To achieve the above objectives, we have developed a portable PM2.5 measurement system for cold regions, conducting multi-location observations of air quality such as PM2.5, analyzing large-scale global data (satellite, model, re-analysis data, etc.), and conducting research using various methods such as machine learning prediction (we are also conducting joint research with NASA and interdisciplinary research).

    Teppei J. Yasunari Specially Appointed Associate Professor
    Ph.D. in the field of Earth System Science
  • Communication Robot System

    Social space recognition system using dialogue activity and attention guidance system and multiple robots

    By calculating the level of activity of a dialogue between people, a robot can recognize the intensity of that dialogue space and adapt its behavior to the context. Furthermore, by applying this mechanism to the behavior of multiple robots, it will become possible to guide the user's attention.

    Research

    Our dialogue activity calculation system calculates the real-time activity level using information such as the distance between the interactants, voice data, and body movements. By using this activity level, the robot can determine whether it is allowed to enter the dialogue space or interrupt the dialogue, and can take contextually adaptive actions. Furthermore, by having multiple robots act in a way that increases the dialogue activity level for each other's actions, the user's attention (e.g., gaze) can easily be guided. Such a system for generating robot behavior using the level of dialogue activity has not been included in conventional research on social robots, and can be applied to robots at reception desks and home robots for households.

  • Discovery and Application of a Novel Enzyme Capping the N-Terminus of Peptides

    Novel peptide ligase

    ・We discovered a novel enzyme catalyzing the attachment of non-proteinogenic amino acids to the amino termini of various peptides.
    ・It is expected to lead to the protection of useful bioactive peptides and the development of new anti-tuberculosis drugs.

    Research

    One of the disadvantages of using peptides as pharmaceuticals is that they are degraded by peptidases. Since exo-type peptidases acting on peptide termini are mostly responsible for degradation in humans, attachments of non-proteinogenic amino acids to the peptide termini is valuable from the viewpoint of protecting them from degrading enzymes for drug development. In this study, as a result of biosynthetic studies of the peptide antibiotic pheganomycin, we found an enzyme that capped the amino terminus of various peptides consisting of 2 to 18 amino acids with a phenylglycine derivative, which is a non-proteinogenic amino acids. To understand the broad substrate specificity, we solved the crystal structure of the enzyme and found that the enzyme has a large substrate binding site, which is not found with other enzymes, and that can thus accept a variety of substrates. Nat. Chem. Biol., 11, 71 (2015).

  • Elucidation of Nutrient Sensing Mechanisms in the Digestive Tract

    Regulation of blood glucose by food peptides through their effects on the enteroendocrine system

    Hormones secreted by endocrine cells that sense nutrients in the gastrointestinal tract regulate various physiological responses immediately after eating. In the course of studying this mechanism, we found through animal studies that food peptides can promote the secretion of the gastrointestinal hormone GLP-1 and reduce the elevation of plasma glucose levels.

    Research

    Various gastrointestinal hormones released by enteroendocrine cells that sense nutrients in the digestive tract, play an important role in regulating various physiological responses after meals. We have focused on the gastrointestinal hormone GLP-1, which is known as an anti-diabetic hormone, and found a food peptide (derived from corn) that strongly promotes the secretion of GLP-1. By orally administering this peptide to rats, we found that GLP-1 secretion was promoted and plasma glucose elevation was suppressed. Our research is aimed to elucidate how this peptide is recognized by enteroendocrine cells, and to control postprandial plasma glucose levels and appetite by controlling the secretion of gastrointestinal hormones with various food components.

  • Development of Den-type Traps to Reduce the Cost of Non-native Raccoon Control

    To establish an effective and efficient pest control method in low-density situations

    We have been conducting research on measures to control alien species that have been brought into Japan, with the aim of proposing effective control technologies and strategies that can match the ecological and behavioral characteristics of the target species and respond to the conditions of human society. In this study, we developed an efficient trap based on the tree-cave nesting habit of raccoons.

    Research

    Control of non-native raccoons, which are increasing in number and causing damage in Hokkaido and other parts of Japan, is an urgent policy issue, and reducing the cost of the prolonged control project is the most important issue in the field. Conventional trapping methods rely only on box traps with bait, and require daily patrols and inspections regardless of whether raccoons have been trapped or not, to prevent bycatch of other animals and to replace bait, and the amount of work does not decrease, even after the population density has been reduced. The den-type trap developed in this study, based on the nesting habit of raccoons in tree caves, does not require bait to attract raccoons, reduces bycatch, and eliminates the need for daily inspections, thereby keeping the cost of pest control extremely low. The trap is also equipped with a system that allows the office to receive capture information via radio waves, making it possible for a small number of people to implement a wide range of pest control measures with a low budget.

    Tohru Ikeda Emeritus Professor
  • Application of Adhesive Gels to Intraoral Devices

    Innovation for maintaining intraoral devices with adhesive gel

    Intraoral appliances used in dentistry need to be clasped or otherwise attached to the teeth to remain in place. This research involves the development of prototype intraoral floor appliances (e.g., palatal obturator) that are attached to the skin or mucosal side of a polycarbonate frame using PCDME or other types of adhesive gel.

    Research

    When an intraoral appliance in this study is used as a palatal obturator, it does not require a clasp, unlike conventional palatal obturators (Fig. 1), because the adhesive gel can be fixed by contact with the oral mucosa. As a result, gingivitis caused by the clasp can be reduced; interference with the sideways growth of the row of teeth can be avoided; it can be comfortably worn without a sense of tightness or pressure; and it is safe to put on and take off the palatal obturator without damaging the oral cavity. It can also be worn before the teeth have erupted, allowing language training to begin at an early stage. The gel can also be thinly spread on the thin frame, and a uniform thickness can be obtained. This reduces the sense of discomfort when wearing the product and ensures a larger oral space, which is effective for language training by expanding the area where the tongue can move.

  • Development of the Evaluation Framework and Methods for Museums

    Revealing social and economic values and experimenting with participatory evaluation

    Self-evaluation of museums within an appropriate framework is necessary to obtain hints for learning and improvement, and promote information disclosure. With this study, we will examine the framework and evaluation methods together with museum staff, and support the process until the actual operation of evaluation activities.

    Research

    Our research is aimed to communicate the value of museums to society at large through evaluation and to establish the recognition of such value. Conventional evaluation methods have focused only on the academic and cultural values that visitors gain from a museum. As a result, the evaluation results were only conveyed to a limited number of museum workers and enthusiasts. Their contribution to business improvement has also been insignificant.
    In this research, we will examine an evaluation framework (see figure) and methods that focus on social and economic values created by the existence of museums in local communities, including many non-visitors, and disclose these values. In addition, we will try various evaluation methods, such as participatory evaluation, which is effective for learning and improvement, and use them to improve our projects. Through these efforts, it will be possible for museums to become more everyday places for citizens and an indispensable part of local communities.

  • Estimating the State of Radio Waves Using the Compressed Sensing Method

    Toward highly accurate location estimation and channel prediction

    The compressed sensing method is a method to find a solution under certain conditions from a smaller number of observation data than the number of unknowns required. In this study, we use compressed sensing for estimating the direction of arrival of radio waves, to predict the channel, and detect scatterers.

    Research

    It is usually impossible to specify unknowns if their number among observation data is smaller than the number of unknowns that need to be found. However, in case the majority of unknowns are zero, it is sometimes possible to obtain the exact solution. Compressed sensing is a method for obtaining an accurate solution while minimizing the number of observations by using this property. In our laboratory, we are investigating the application of this method to high-precision estimation of the direction of arrival of radio waves as shown in Fig. 1, a method of channel prediction by dividing the incoming wave into elementary waves using this method (Fig. 2), and scatterer detection using the compressed sensing used in radar systems (Fig. 3).

  • Infrared Metamaterials Produced by Microfabrication of High Temperature Resistant Materials

    Development of materials and devices that manipulate mid- to far-infrared radiation

    It is expected that it will be possible to make devices to control corresponding electromagnetic waves by creating heaters and diffraction gratings with patterns smaller than the mid- to far-infrared wavelengths. We are developing methods to fabricate thin films, stacks, and microstructures of metal carbides and oxides, and are studying their elemental characteristics.

    Research

    Materials that are finely processed on a scale of less than the wavelength of electromagnetic waves can control the reflection and transmission of electromagnetic waves (such materials are known as metamaterials). Mid- to far-infrared radiation, with wavelengths ranging from 3 μm to 1000 μm, can be used for the detection of molecules as it is an electromagnetic wave that is related to heat radiation and can excite molecular vibrations. Since it is a heat-related material, being heat-resistant would render it usable for applications that cannot be realized elsewhere. We are studying process technology for heat-resistant materials with various properties such as metal carbides and oxides, and are measuring the fundamental properties of these materials in the infrared region for application to metamaterial design. By fabricating metamaterials for mid- to far-infrared radiation, we aim to create narrow linewidth mid-infrared light emitting devices for molecular detection and materials for controlling radiation heat.

  • Classification of Genetic Information Using Machine Learning

    Predicting the binding of compounds to cell receptors

    Various receptors on the surface of cells play important roles in maintaining homeostasis and environmental responses, but it is difficult to identify compounds that can bind to them. We propose a method for narrowing down the candidates for binding compounds by using machine learning.

    Research

    Although the human genome has been deciphered and many of the genes have been elucidated, the structure and function of receptors, which play an important role in homeostasis and environmental responses, have not been fully elucidated, because most of them are membrane proteins and their expression levels are low. Many receptors, however, are expected to be major targets for drug discovery in the future because of their functional aspects, and are thought to be the factors that cause individual differences. We are applying machine learning technology to efficiently narrow down compounds that can bind to receptors.

  • Micro-/nano-patterns Created with Biomaterials

    Bio-based micro-/nano-patterns that mimic biological structures for application to cell culture tools and tissue regeneration

    Using biomaterials such as collagen and dental materials, we are producing micro-/nano-patterns that mimic biological structures. Depending on the shape of the pattern and the type of material, it can lead to the improvement of cell functions. While pursuing new possibilities, we aim to apply our technology to cell culture tools and periodontal tissue regeneration.

    Research

    In this study, we are using nanoimprinting to pattern typical biomaterials. We hope that the designed micro-/nano-scale shapes can be used to control cell functions and contribute to the development of novel cell culture tools and tissue regeneration.
    ● Comparison with conventional technology: It is characterized by unprecedented production of regular biomaterial patterns, and is expected to contribute to the discovery of new functions. (*Conventionally, irregular, flat or industrial plastics)
    ● Effectiveness: Patterning greatly improves the number of cells attached and the degree of elongation compared to flat surfaces. It also makes it easy to align cells in grooves. This can lead to the 3D construction of extracellular matrix (ECM).
    ● Future vision: We aim to regenerate tissues with a similar structure as that of living organisms by developing patterned materials not only in a flat plane but also in 2.5 and 3 dimensions through further layering.

  • Consolidated Compact City Planning

    Methodology for urban consolidation in an era of a declining population

    Our laboratory is the first in Japan to propose and implement the concept of a consolidated compact city, which is a top-priority issue for cities in the age of a declining population. In Yubari, a city where the population is rapidly shrinking, we have proposed the concept of a consolidated compact city, implementing a project to consolidate the urban area in collaboration with the city and local residents.

    Research

    This is the first attempt in Japan to implement a consolidated compact city project. In Yubari, we are promoting reorganization into an urban area of an appropriate size through downsizing, while creating a system of relocation and settlement to form local communities, and reduce the maintenance and management costs of urban infrastructure facilities. In the course of creating a compact city, we promote consolidation of the urban area for the first 10 years while maintaining local communities, and then consolidate local communities into a central urban hub over the next 10 years. This allows residents to continue living in Yubari at ease, even while the consolidation process is under way. In cooperation with Yubari City, we have already completed the relocation and consolidation of residents in the Mayachi district of Yubari.
    Our efforts have been published in research papers and the mass media, and we have received many inquiries from cities facing similar issues.