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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.
Takuya Yamamoto Associate Professor -
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. 2088-2093Tamaki Shibayama Professor -
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.Tamotsu Kamishima Professor -
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.
Tatsuya Kikuchi Professor -
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.
Tatsuya Kikuchi Professor -
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.
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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.
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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)
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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/).
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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 ProfessorPh.D. in the field of Earth System Science -
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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.
Tetsuo Ono Specially Appointed Professor -
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).
Tohru Dairi Professor -
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.
Tohru Hira Associate Professor -
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.
Tomoo Kaneko Lecturer -
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.Toru Sasaki Specially Appointed Professor -
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).
Toshihiko Nishimura Professor -
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.
Toshihiro Shimada Professor -
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.
Toshinori Endo Professor -
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.Tsukasa Akasaka Associate Professor -
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.Tsuyoshi Setoguchi
