Research

Sialylation (addition of sialic acid) of glycans and glycoconjugates is an important biomarker involved in various biological phenomena such as development, differentiation, disease, infection, and immunity. MALDI (matrix-assisted laser desorption/ionization) is a simple and sensitive soft ionization method. However, the ionization efficiency of unmodified sialic acid-containing glycans is low, and there is a problem that the spectrum becomes complicated due to cleavage of sialic acids or other reasons. With this technique, we succeeded in measuring sialylated glycans and glycoconjugates with high sensitivity and high resolution without undergoing any modification process by improving the addition system to the conventional matrix while suppressing sialic acid desorption. With the change in the cleavage pattern and the increased sensitivity, TOF/TOF analysis and pseudo-MS3 analysis can now be performed using ultra-trace samples. This method does not require chemical modification and separation steps, and enables reaction tracking and rapid sample analysis.

Research

Cellulose synthesized by bacteria and called bacterial cellulose (BC) has unique properties such as high water retention, high strength, biodegradability, and biocompatibility. In recent years, nano-sized cellulose materials (nanofibrillated cellulose (NFC)) has also been attracting attention. In general, NFC is prepared top-down from pulp by physical and chemical treatments, and the resulting NFC is highly dispersed in water. In contrast, by optimizing the culture conditions of cellulose-synthesizing bacteria, it is possible to prepare nanofibrillated BC (NFBC: Fibnano?) from low-molecular biomass in a bottom-up manner. In collaboration with a company in Hokkaido, we have succeeded in the mass production of NFBC (Fibnano?) from molasses, a byproduct of sugar production.

Research

In the field of information science and engineering, many problems appear, such as the problem of designing a mathematical system that provides a desired result, the problem of identifying a mathematical model that gives a given input and output, and the inverse problem of estimating unknown inputs from a system and observations. When dealing with these problems, by dividing the analysis into conditions specific to each problem and mathematical models independent of each problem, it becomes possible to theoretically determine the performance and limitations, and to also expand the analysis horizontally to problems that can be described by similar mathematical models. With this unique approach, we have developed various methodological constructs and application techniques in machine learning problems including image and color restoration, separation of individual sounds in acoustic signals, pattern recognition, and sampling theory. By applying our methodology to today's rapidly developing and diverse measurement technologies, we expect to develop a variety of application techniques based on theory.

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.

Research

The hardness test, a method to clarify the strength of materials from the deformation caused by local loading, is widely used based on its high simplicity and reproducibility. To obtain highly accurate stress response information while taking advantage of the simplicity of this method, we have developed in-situ hardness tests (micro-indentation) method.
To observe the surface of the specimen both inside and around the indentation through a transparent indenter during the indentation test, it is necessary to optimize the optical conditions. However, by introducing a liquid with a refractive index close to that of the transparent indenter around the indenter, we have enabled a wide range of surface observations.

Research

The mitochondria-targeted nanocapsules (MITO-Porter) in this study can pass through the cell and mitochondrial membranes to deliver target molecules inside the mitochondria. Conventional technologies using functional elements severely limit the size and type of molecules to be delivered, but the strategy using MITO-Porter, which encapsulates the target molecule, enables mitochondrial delivery independent of the molecular species.
When we prepared MITO-Porter with GFP (green) encapsulated and observed intracellular fluorescence microscopy, we observed many yellow signals that overlap with mitochondria (red), confirming efficient molecular delivery inside the mitochondria. We have also succeeded in introducing genes and nucleic acids into mitochondria, which had been impossible with existing nucleic acid delivery agents (targeting the nucleus and cytoplasm). We are also developing nanocapsules that can be adapted to living organisms.

Research

In this laboratory, we have developed a method to extract the output of renewable energy (RE) power generation hidden in the information of power flowing through distribution lines in real time by applying a signal analysis technique called independent component analysis (ICA). This method enables highly accurate output estimation without having to use preliminary information such as the installed PV capacity in the grid (Fig. 1).
We have also developed a control method to compensate for RE power output fluctuations using storage batteries (Fig. 2) and simulation technology to estimate the storage battery capacity required to suppress output fluctuations for individual wind farms and mega solar power plants.

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

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.

Research

We have fabricated CaYAlO4 single crystals doped with chromium (Cr) and neodymium (Nd) using a technique called the floating zone melting method. By appropriately controlling the fabrication conditions, high-quality red transparent crystals were obtained (Fig. 1). The crystal has a very wide absorption range from the ultraviolet region to the visible region, and shows sufficient absorption even at the wavelength where the energy of sunlight is at its maximum (Fig. 2). We have also found that the absorption is 70 times or more that of conventional materials such as Cr and Nd:YAG. These properties are unique to the newly developed crystal and not found in existing materials. We have also demonstrated that neodymium can emit light upon excitation in the absorption band of chromium due to its fluorescence properties (Fig. 3). Based on this result, it is expected to convert solar energy into laser light with high efficiency.

Research

Until now, chemical reaction phenomena in thermo-fluid (CFD) analysis have been modeled simply by assuming an infinitely fast reaction or an overall reaction model consisting of a few chemical species and reaction equations due to computational load and lack of analysis techniques. On the other hand, when the interaction between chemical reactions and fluid phenomena is important, such as in the case of unsteady phenomenon prediction like the ignition timing of automobile engines or ultra-dilute combustion under extreme conditions, it is difficult to apply simple models. Our research group has solved the problem of applying detailed reaction mechanisms to CFD analysis. The proposed method consists of a time integration method (ERENA) that can significantly reduce the calculation time of chemical reaction equations, and a species bundling technique that combines similar chemical species. Depending on the conditions, the proposed method can be tens to hundreds of times faster than the conventionally used methods while maintaining equivalent accuracy.

Research

To develop a new grout with low environmental load, we focused on minerals produced by living organisms in nature (biominerals), especially CPC, a major component of teeth and bones, and investigated the optimum conditions for CPC precipitation. We also conducted uniaxial compression tests on sand specimens solidified with CPC. In the CPC precipitation test, we have found that the precipitation volume tends to increase as the pH increases from weakly acidic to near neutral. This causes the uniaxial compressive strength of the CPC-solidified sand specimens to reach about 90 kPa, which is within the target range of 50 to 100 kPa for uniaxial compressive strength of sandy soil to prevent liquefaction. Electron microscopy of the specimens showed whisker-like CPC crystals (Fig. 1). These results indicate two possibilities of their usage: chemical grout using self-hardening property and biogrout using pH-dependent precipitation volume.

Research

In terms of the present situation concerning sports, various forms of image and video distribution have spread, and a new environment for watching sports is being established, whereby related data along with images and video footing can be viewed via smartphones and other mobile terminals. However, with soccer, it is only possible to view basic data such as free kick success rate and running distance. This research analyzes various data obtained from users and their surrounding environment to help them understand and visualize the data to accelerate knowledge sharing, even when the relevant knowledge and experience are essential. Examples include ball passing and the degree of dominance. Since the visualization technology of this research can obtain various data surrounding the user and provide various kinds of information in a way that is adaptable to the user's environment, it has high potential for application to the fields of IoT and AI, and is expected to contribute to the creation of new technologies in these fields.

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.

Research

The significant drag reduction in turbulent channels due to the addition of a small amount of long-chain polymers or surfactants that form rod micelles in water, is known as Toms effect. A model that simulates polymers with small dumbbell-shaped elements was constructed, and direct numerical simulation (DNS) of turbulent flow in a two-dimensional channel was performed using this model to reproduce Toms effect. It was shown that the discrete element has two mechanisms: one is a resistance reduction mechanism due to the longitudinal vortex damping, and the other is a resistance increasing mechanism due to the additional stress near the wall. Furthermore, by adding the effect of cutting the element to which a strong force is applied, we were able to reproduce the feature that drag reduction occurs in a specific Reynolds number range.

Research

We invite, select and implement proposals for the effective use of stable isotope imaging technology, which is a special feature of the isotope microscope system, to expand it to industrial innovation.
Upon hearing the word, “isotopes,” the concept of “age measurement” immediately comes to mind. Actually, until now, isotope microscopes have been used to analyze isotope ratios, primarily in minerals and other areas of space science. This is a result obtained by observing the as-is cross-section of the obtained sample. However, by changing the concept of the measurement method, we can expand the use of isotope microscopes to industrial application. In other words, by actively doping a target sample with an isotope element, rather than observing it “as such,” it becomes possible to measure the desired imaging we were unable to see before. The use of stable rather than radioactive isotopes also allows us to work safely.

Research

In holographic diversity interferometry, multiple image sensors are arranged in combination with a polarizing optical element to enable precise detection of optical phase distribution in a single measurement without spatial completion error. We have developed an interferometric optical system using two image sensors and have greatly improved the measurement algorithm to achieve highly accurate phase measurement and enable 3D information processing using the measured phase distribution data. This technology can be applied directly to the acquisition of 3D optical information, optical tomography by digital phase conjugation, and 3D optical memory. In this research, we have also succeeded in developing a reference light-free phase detection system that filters the signal light spatially filtered and re-interacts with the signal light. This is expected to find applications in next-generation ultrahigh-speed optical communication systems using spatial modes and in the field of remote sensing.

Research

Advanced composites (carbon fiber composites, carbon fiber reinforced plastics (CFRP)) are widely used as structural materials due to their high specific strength and stiffness. The development of fiber orientation technology has made it possible to arrange fibers not only in straight but also curved lines. Compared with straight fibers, design flexibility is greatly improved, and it is thus possible to produce CFRP components for specific part shapes and uses. In our laboratory, we have been producing composite specimens with curved fibers using a fiber stitching machine (Fig. 1), which is based on embroidery machine technology, to evaluate the mechanical properties of specimens and develop a unique method to optimize fiber shapes. For example, Figure 2 shows the optimum fiber shape to reduce the strain concentration around the holes in a wing model with multiple circular holes, and the strain distribution is shown in Fig. 3. It has been found that the strain concentration is reduced more than with straight fibers.

Research

Cyclic peptides are an ideal molecular form for exploring biologically active compounds (drug discovery) and the design of molecular tools in life science. Cyclization of the peptide backbone can control their conformational stability, orientation, and symmetry. However, peptide cyclization requires specific dilution conditions and complex basic protection strategies. We found that combining a hydrogen-bond-controlled solvent system and a base-free condensation agent system enables the efficient cyclization of poorly soluble peptides under highly concentrated conditions. The simplicity of this technology gives a wide range of applications for drug discovery and life sciences by facilitating the free design and mass production of cyclic peptides.

Research

The transport properties of porous materials such as concrete does not only depend on the porosity, but also on the spatial distribution of each phase. Therefore, the transport properties of HCP, which is a main component of concrete, was predicted. Figure 1 shows a cross section of HCP observed using a backscattered electron image, showing the distribution of each phase. We extracted each phase, calculated the autocorrelation function, and based on the results, distributed each phase in three-dimensional space to construct the three-dimensional spatial image model shown in Fig. 2. Figure 3 shows a comparison of the results of the diffusion coefficient calculated by the finite difference method and the measured values. The estimated and measured values agreed well with each other, even for different samples, indicating that the diffusion coefficients of hardened cement can be predicted using this model.

Research

Since the amount of data handled during image processing is generally huge, it is essential to optimize the system as a whole by combining hardware and software. In this laboratory, we are investigating the configuration of image processing systems by studying image processing algorithms and their implementations complementarily. One of the results of our research is real-time adaptive brightness correction of video images based on the Retinex theory (Fig. 1), which can adaptively correct the brightness of video images taken under conditions of large changes in illumination, such as backlighting, in real time. We are also working on high-quality image smoothing (Fig. 2) based on cost optimization, which is expected to be applied to image processing such as photo illustration, pre-processing of various image processes, brightness correction, and detail enhancement.

Research

We are researching technologies for the automatic recognition and modeling of objects and structures in indoor and outdoor environments from point clouds obtained by ground-based and vehicle-mounted 3D laser scanning systems, as well as basic point cloud data processing methods. The objects to be recognized and modeled include a wide range of arbitrarily shaped objects, rooms, pole-like objects such as utility poles and street lights, trees, road surfaces, and buildings. In addition to the technology of generating mesh models, polygon models, and CAD models from point clouds, we also conduct research on point cloud registration, segmentation, shape feature extraction, machine learning, and procedural object recognition that serves as the foundation for the technology. This technology enables detailed recognition and analysis of the environment and structures, maintenance and management, various simulations and improvement plans using 3D models that faithfully reflect the current state.

Research

In today's internet society, recommendation technology, if it works well, can benefit both the provider and the receiver of the service. A recommendation service is not a one-time event, but an iterative process with feedback each time, and the feedback only concerns the items that are recommended. Therefore, to increase the accuracy of subsequent recommendations, it is not only important to recommend items that the user is likely to like based on the feedback history (knowledge utilization), but also items from which the user is likely to acquire more information (knowledge acquisition). The Bandit method attempts to maximize user satisfaction by balancing the use and acquisition of knowledge. We are developing a recommendation system using this method.

Research

In the study of earthquakes and volcanic activity, the Earth's interior is sometimes estimated by capturing slight movement of the Earth's surface. This movement is called crustal movement, and efforts are still being made to improve the estimation accuracy and quality. Recently, interferometric SAR (SAR interferometry), which uses satellite SAR phase data, has made it possible to detect crustal movement in remote areas and overseas. In the Arctic, there is no so-called crustal movement, but as shown in the figure below, clear ground deformation has been detected in Western Siberia. This can be seen around so-called thermokarst terrain, which is often found in the Arctic, and is thought to represent subsidence of the ground surface due to the thawing of permafrost. Research on the formation process of thermokarst landforms, which has been largely untouched in the past, has just begun, and evaluation of the impact of global warming is an important issue for the future.

Research

The primary purpose of my research is to identify the unique communication phenomena that form within organizations. In my research on pure risk, I explored internal/external organizational public relations, especially as pertaining to product accidents and the internal risk communication in organizations handling hazardous materials. I believe that communication that is created/disturbed/diffused/structured within an organization and that has some kind of inherent meaning/value for the organization will lead to novel organizational strategies, and that is what characterizes my research and makes it unique. In this regard, I have recently been examining how social organizations (e.g., photography) are organized and the intentions of it.

Research

We are proposing spin devices that exceed the current mainstream CMOS devices in terms of performance and power, and are analyzing their performance using condensed matter theory. The main objective of this research is to create power-saving devices that provide superior performance to CMOS devices. To calculate the performance of novel spin devices, quantum field theory and relativity are used to calculate the spin conductivity and other properties. Currently, we are studying topological insulators and skyrmions. Topological insulators are bulk insulators, but spontaneous spin currents flow only on their surfaces. If successfully applied to devices, topological insulators make it possible to fabricate ultra-low power devices because the topological insulator itself is non-dissipative. Skyrmions are also a peculiar vortex generated in magnetic materials, and are expected to play the role of a switch by driving a current.

Research

The quantum key distribution technology has passed the proof‐of‐principle phase, and research is now under way with an eye on its practical application. Since this is a technology to realize the ultimate confidential communication, field tests and other researches on it are conducted worldwide. In our laboratory, we are examining both theoretical and implementation-related aspects on quantum key distribution. In the real world, things do not always go according to the theory, and experimental results sometimes differ from those expected in theory. Our goal is to examine these discrepancies and quantitatively guarantee the security of cryptographic keys produced on real devices. To this end, we are conducting research to fill the gap between the theoretical studies and the actual device development. We believe that this research will open the way to measure and evaluate the behaviors of the actual quantum devices, and finally to realize practical quantum systems, which will contribute to future quantum networks.

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.

Research

As telecommunication devices increase in capacity and become more sophisticated, semiconductor devices are becoming more and more integrated. However, there is concern that cosmic ray neutrons may cause an increase in soft errors, such as bit information upset and operation confusion. Therefore, in collaboration with NTT, we have reproduced soft errors using a compact electron accelerator-driven neutron source to create a place to develop countermeasure technologies in advance. This enables the advance prediction of the failure rate in the natural environment, the detection of errors and verification of operational measures, which will lead to improved reliability of the equipment.
The feature of this technology is the use of a compact accelerator-driven neutron source. In the past, large-scale accelerator-based neutron sources were required, and it was difficult to secure sufficient test time and experimental space. However, through our research, we have demonstrated that it is possible to conduct sufficient tests even in a facility with a neutron intensity of several million times that in nature.

Research

Plasmas generated in liquid are of great interest in the fields of nanotechnology, environmental engineering and medical engineering, but the need for high voltage to generate the plasma can be an obstacle. Meanwhile, in the field of ultrasonic engineering, it is known that the interior of a bubble becomes plasma at the same time as the collapse of acoustic cavitation. Using a very simple method of inserting a perforated metal plate into a liquid where ultrasonic waves are applied, we have succeeded in localizing and efficiently generating acoustic cavitation, which is difficult to fix in position. This has been valued as a unique method of generating plasma in liquid without using high voltage. Currently, we are working to clarify the mechanism of this method and to prepare guidelines for the design of a large-scale device. In the future, we hope to develop various new plasma application technologies.

Research

○ Acoustic perforation (sonoporation) using microbubbles and pulsed ultrasound: Pulsed ultrasound irradiation of microbubbles in contact with the cell membrane enables temporary perforation only at the attachment site (Fig. 1). We have realized a method to deliver drugs or genes into any desired position in the target cell by adding drugs or genes to the microbubbles and controlling the attachment site with optical tweezers.
○ Succeeding with therapeutic site identification and drug delivery by using microbubbles and an ultrasound system: A microbubble, which has the target function of adhering only to the cells to be treated, is injected into a vein. To identify the therapeutic site, the tissue where the bubbles have accumulated is detected using an ultrasound contrast method. Pulsed ultrasound waves are then generated to break the bubbles, allowing temporary perforation of the cell membrane and drug delivery (Fig. 2). By adding drugs or genes to the bubbles, highly efficient drug delivery only to the target cells can be realized.

Research

Optical information processing, transmission, recording and reproduction are performed using the intensity, polarization and spatially uniform phase of laser light. The transmission capacity can be increased through multiplexing using different frequencies. In contrast, the spatial characteristics of light form an unexplored area that has not been actively utilized until now. Based on this background, information multiplexing using Laguerre-Gaussian (LG) light and quantum information processing using the orbital angular momentum (topological charge) that characterizes LG light have been attracting attention as a step to overcome the limitation of information processing capacity. In this study, we have utilized material interaction and realized the mode control of LG light and the conversion and conservation of orbital angular momentum using short-pulsed light, as well as space-division multiplexing fiber transmission.

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.

Research

Based on our previous research results, we have discovered that when a droplet hits a solid surface in a condensable gas (not air), splashing is suppressed and a thin liquid film (lamella) spreads on the solid surface at high speed. Since the high-speed lamellae may generate a strong fluid shear force, it seemed possible to use a mixed jet of steam and water to realize an environmentally friendly cleaning method.
Based on our previous research results, we have confirmed that this cleaning method, which uses only water and steam, can achieve the specified cleaning performance for ultra-precision cleaning required in the manufacturing processes of semiconductors, LEDs, and solar cells. This cleaning method is also safe both for the human body and the environment, because it uses only water and steam instead of detergents or other chemicals that are harmful to the human body.

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.

Research

It is expected that superomniphobic surfaces, which do not get wet with water or oil, will possess antifouling and self-cleaning properties. In this study, we have realized a superomniphobic surface that does not only repel water but also octane and other liquids with a surface tension as low as 20 mN m-1, by using a simple wet process for aluminum, which is a practical metal material. This process can also be applied to aluminum foil, which can be used as an antifouling surface in various places. It can also be used as a filter to separate oil and water by controlling its wettability using aluminum mesh.

Research

The introduction of fluorine atoms into organic compounds is very important in the fields of medicine, agrochemicals, and functional materials. There is a method of synthesizing fluorine-containing organic compounds by using fluorine-containing building blocks, but such compounds are still expensive and limited in quantity, and there is a high need for research and development. In this study, we succeeded in synthesizing fluorine-containing aromatic carboxylic acids with various functional groups from readily available fluorine-containing aromatic compounds and carbon dioxide, and achieved good yields using the organic electrolysis method. The fluorine-containing aromatic carboxylic acids synthesized in this study include a variety of new compounds that are difficult to synthesize by conventional methods, and are expected to be used as promising new fluorine-containing building blocks for the synthesis of pharmaceuticals, agrochemicals, and highly functional materials.

Research

Glycan patterns on glycoproteins are important biomarkers because they are factors that determine the disposition of protein in the body. Until now, glycan pattern analysis has required complicated operations such as cutting, chemical modification, and purification of glycans. Mass spectrometry is an ultra-sensitive and high-resolution analytical technique that can directly ionize trace amounts of biomolecules. However, there has not been a method to selectively ionize glycoconjugates such as glycoproteins and glycans in complex macromolecules and mixtures such as body fluids, which requires the complicated pretreatment described above. We have achieved the world's first simultaneous selective cleavage and selective ionization of glycoconjugate glycans, and succeeded in the direct analysis of glycan patterns on glycoproteins. We have also demonstrated that this technique can be used to directly analyze glycan patterns in complex mixtures such as egg white.

Research

Microarray technology is a technology that enables simultaneous comparative analysis of the interaction between a large number of compound libraries with well-defined structures and sequences and sample components. We also have the most advanced technology to design and produce our own carbohydrate compound libraries as molecules for microarray analysis based on our automated carbohydrate synthesis technology. The interaction information possessed by carbohydrates is widely used as biomarkers for in vitro diagnostics, such as blood types, serotypes such as O157, and cancer diagnostic markers (CAxx). In addition, we have succeeded in developing an independently powered mobile analyzer that can be used for online diagnosis, such as analysis of infection patterns associated with mutations in infectious diseases and detailed analysis of vaccine effects, by performing specimen collection and microarray analysis on the spot using a smartphone as a terminal.

Research

Visualization of acoustic wave propagation is extremely useful in the evaluation of physical properties and the design, fabrication and evaluation of functional devices using acoustic waves. For this purpose, we excite surface acoustic waves by irradiating the sample with an ultrashort optical pulse of subpicosecond duration (pump light), and observe their propagation with delayed optical pulse (probe light). Time-resolved two-dimensional images of the acoustic waves are obtained by scanning the delay time and the irradiation position of the probe light. The time resolution is in picoseconds, the spatial resolution is 1μm, and the frequency range is in GHz. Since this method uses a periodic optical pulse train, it was previously only possible to excite and detect acoustic waves at integer multiples of the repetition rate. However, with the newly developed technique, we have realized the excitation and detection of acoustic waves of any frequency. By developing this technique, we have also achieved image vibrations that are completely asynchronous to the repetition frequency of the optical pulse, thereby expanding the range of applications.

Research

Thanks to the development of molecular targeted therapies, antiangiogenic agents are now widely used. However, there are problems such as the lack of companion diagnostics to predict therapeutic effects and side effects due to injury to normal blood vessels.
We have successfully isolated and cultured human tumor vascular endothelial cells and have identified specific markers that they express. Tumor vascular endothelial cells expressing these markers are valuable materials for cell-based screening of novel drugs and compounds, and help us identify new therapeutic targets and drugs that cannot be discovered by studies using conventional tumor cell lines or clinical tumor tissue fragments. Markers expressed by these tumor vascular endothelial cells can also be used as companion diagnostics. This will contribute to the realization of personalized treatment by selecting the target cases as well as the timing and duration of administration with angiogenesis inhibitors.

Research

In a seismically-isolated building, the seismic isolators deform softly during an earthquake, greatly reduce response acceleration in the superstructure and improve the seismic safety. On the other hand, ultimate events such as collisions with retaining walls and buckling or rupture of the seismic isolation bearings may occur for the ground motions exceeding design level caused by a mega earthquake such as the Nankai Trough Mega Earthquake. By using analysis technologies to precisely predict the ultimate behavior of seismically-isolated buildings, it is possible to foresee the occurrence of ultimate events and to consider countermeasures to suppress their occurrence.

Research

We have succeeded in obtaining titanium dioxide thin film on a practical metal substrate such as Cu, Al, Zn and Fe by electrolysis from an aqueous solution containing TiF62- within only a few seconds. The obtained titanium dioxide thin film is anatase crystalline and shows photocatalytic activity without heat treatment. The obtained titanium dioxide thin film is anatase crystalline and shows photocatalytic activity without heat treatment. We have confirmed that it has excellent properties such as decomposition of organic contaminants on the surface by UV irradiation and superhydrophilicity. Since the titanium dioxide film is doped with substrate elements, the development of new functions such as visible light responsiveness can be expected. It can also be deposited on a transparent conductive substrate.

Research

As in Fig. 1, which shows the principle of laser-induced excitation force generation, the laser-induced excitation force is caused by laser ablation. Figure 2 shows an example of the application of this technology, a vacuum environmental excitation measurement system for a membrane structure. This system consists of a YAG-pulsed laser, dielectric multilayer mirror, collecting lens, membrane structure, LDV and vacuum chamber. The membrane structure is fixed inside the vacuum chamber, allowing us to conduct the experiment by adjusting the air pressure inside the chamber from the atmospheric to the vacuum environment. Figure 3 shows the measured frequency response of the membrane. As shown in Fig. 3, with an increase in the vacuum level, the resonance frequency of the membrane becomes higher and at the same time the resonant response level increases. In this way, this technology enables the extraction of both mass effect and damping effect caused by the air on the membrane surface. We have conducted experiments to verify the effectiveness of this technology in a vacuum chamber, which assumes a space environment.

Research