本学では創立者大隈重信を記念し、学術の振興をはかることを目的として、研究上顕著な業績をおさめた教員に対して、大隈記念学術褒賞を授与しています。
このたび本学術院の川原田　洋名誉教授、高西　淳夫教授（創造理工学部 総合機械工学科）が大隈学術記念賞を、平田　秋彦教授（基幹理工学部 応用数理学科）が大隈学術奨励賞を受賞されました。

授与式は2025年12月11日に大隈会館にて執り行われ、田中　愛治総長より正賞と副賞が授与されました。

大隈学術記念賞

川原田　洋名誉教授
研究題目「ダイヤモンド高濃度正孔層による FETの高周波、高電圧、バイオ、超伝導分野での先駆的応用研究」

高西　淳夫教授
研究題目「二足歩行ヒューマノイドの研究とその応用分野の開拓」

大隈学術奨励賞

平田　秋彦教授
研究題目「アモルファス物質の回折実験および数理手法を用いた構造解析」

川原田名誉教授と田中総長

高西教授と田中総長

平田教授と田中総長

長年のご功績をたたえ、栄誉ある受賞を、心からお祝い申し上げます。

‘Learning Ecosystem’ to Drive Change in the Supply Chain Developed at Waseda

 

Digitalization, globalization and sustainability — and more recently pandemic-driven shifts in economic security, society is undergoing rapid change. Companies’ supply chains are facing an unprecedented era of transformation. Amid this, what can academia do to help restore vitality to Japanese manufacturing and brighten the prospects of the world economy through industry-academia collaboration? Here we introduce a research institute tackling these difficult issues through such collaboration.

◆Contributing to the “great transformation” of supply chains via academic approaches

──When you say ‘Global Production & Logistics’, what kind of research are you talking about?

The short answer is supply-chain management for firms, especially in manufacturing: from procuring raw materials, transporting to production sites, managing inventory in warehouses, and delivering to stores — the whole chain. We also include service-operations management combining sales and consumption.

The environment surrounding manufacturing is especially harsh in Japan now, with layers of complex challenges coinciding — for instance, advances in the so-called Fourth Industrial Revolution, the acceleration of sustainability and social business as symbolized by the SDGs, and rising protectionism following globalization. The pandemic laid bare risks of supply-chain disruption, and with geopolitical risk came a forced reassessment of supply networks.

Especially acute in Japan is the issue of labor shortage. In logistics especially, the so-called “2024 problem” triggered concern over declining transport capability as stricter regulations limited overtime for truck drivers. Not only drivers, but white-collar staff in inventory management and demand forecasting are ageing and leaving the workplace, and the reliance on experienced “intuition” and judgement of veteran workers is catching up with the system.

Amid this backdrop, our mission is to analyze those challenges and examine solutions using knowledge from industrial engineering in order to build the next-generation global production and logistics systems that benefit business and society.

──There seems to be a strong expectation from industry for what academia can bring.

I believe so. Japanese manufacturing once had global leadership, but in recent years the changing environment I mentioned has steadily eroded international competitiveness. In our research we’ve engaged in joint studies and dialogues with top management and supply-chain practitioners at representative Japanese manufacturers. In that process, I’ve felt, more than ever, the rising expectations for academic approaches on how to enact transformation and concrete methods.

What I, personally, have felt from working with many companies is: Japanese firms at the site level have extremely high capabilities and the capacity to improve. Their daily operations are already near optimal, and their accumulated knowledge and efforts are globally enviable.

On the other hand, in our field we have a concept called the “Theory of Constraints”. It states a system’s overall performance is determined by its bottleneck. Like a chain is as strong as its weakest link, an organization or a supply chain is often held back by one constraint.

To achieve dramatic reform, you must change the constraint itself. But that affects other departments or other companies, and may even bring temporary chaos or negative impact, so it is by no means easy.

In that context, I believe the source of future competitiveness for companies is to clearly define the “ideal form” and long-term vision of the company, and advance reform with a whole-system optimization perspective — thereby overcoming that wall.

Our institute’s contribution lies in deeply understanding companies’ visions, organizing decisions into scenarios, building mathematical models and algorithms, and then doing simulations. This allows us to quantitatively show “if this decision is taken, what sort of result will emerge”, and we consider this assistance in strategic decision-making for companies with future foresight to be crucial.

◆Bridging the gap between “theory and reality” through joint research with industry

──What specifically do you do in the management-engineering approach?

For example, in joint research with a nationwide restaurant-chain company, we undertook a project to optimize delivery scheduling to stores. Because multiple stores exist in one region, improving logistics efficiency was the challenge. Previously each store hoped for its own delivery time — one wanted morning, another night — so even neighboring stores might receive two separate deliveries (morning and night) in the same area, which is inefficient. If we relax this constraint of delivering at the time each store demands, and align delivery times, then delivery routes can be consolidated, and fewer trucks can serve them.

Now imagine hundreds of stores in one region. Which stores should have their delivery logistics coordinated to yield the greatest efficiency? We built an algorithm and derived the optimum mathematically from among the vast combinations. By not being swayed by each store’s individual situation but enabling headquarters to take an aerial view and coordinate across them, logistics efficiency improved significantly.

However, a theoretically obtained optimum solution doesn’t necessarily fit the reality of problem-solving. There is always a gap between theory and reality, and it’s important to work with companies to close that gap. For example, if you give maximum consideration to each store’s circumstances, how will transport cost, manpower and time be affected? On the flip side, if you prioritize efficiency, how much burden does that place on the stores? Through such simulations we present several options, and let the company make a judgement.

And not only for delivery: supply chains involve many stages, so by viewing them end to end, if you optimize what used to function separately — different departments and companies — even a small improvement can significantly raise efficiency.

──So it’s research while confronting actual challenges in reality. 

While we often undertake joint research with companies, we first focus on formulating a ‘research question’ from a societal and academic standpoint. We answer that question using scientific methods, and our mission is to connect our findings to problem-solving in society and to creating new value.

Even in joint research we proceed only after the company understands that we’re targeting topics with large societal impact, not just an individual firm’s issue.

Because it is a ‘significant question’, it must be an unresolved problem. An obvious challenge easily solved with existing solutions or methods does not become a research theme. Therefore, in every joint research we’re always facing new challenges, iterating trials and errors, at times experiencing failure together and building up knowledge.

The field of supply-chain is very broad: from operations at the site, through management strategy, to the economy as a whole. It demands multi-layered perspectives. Because the methods and expertise required differ significantly at each layer, we have researchers from a variety of fields participating in the institute.

Also, many practitioners from industry join as research members, bringing awareness of real-world issues and business realities to the discussions. With students also joining these talks among specialists from different disciplines and industries, they don’t just learn theory — they directly experience the complexity of real-world operations and the weight of decision-making, which becomes a great growth opportunity for them.

 

◆Creating a community where university, industry and students learn from each other

──You have been director of this institute for about three and a half years now. What policy have you taken in your research advancement?” 

Including collaboration with companies and overseas researchers, I’ve kept expanding the network. The institute was originally founded in 2002 by my mentor, Professor Kazuho Yoshimoto, a Professor Emeritus of the School of Science and Engineering, with the theme of strengthening the link between production and logistics for productivity improvement. Over 20 years later the environment surrounding corporate management has changed greatly. I believe we should keep daringly taking on new things and systematizing them.

──What new activities have you begun?

We’ve branched out in many areas, but I’ve placed particular emphasis on building communities of practitioners in production and logistics. We’ve held research meetings for manager-class practitioners, meetings for procurement-executives and for logistics-executives — bringing together top runners active in supply-chain management and introducing the latest academic knowledge to them and getting feedback.

We also emphasize overseas collaboration. We work with experts from industry and academia in the USA, Germany, China, Thailand and other countries, learning at various angles about the transformations taking place on the front line of supply chains.

In the U.S. we’ve learned from many advanced cases of supply-chain management. In the “Supply Chain Top 25” published annually by the research firm Gartner, we talk directly with CEOs of companies that are regulars in the list or in the “Masters” category. We gain the opportunity to learn how they drive supply-chain reform and respond to change.

In Germany we’ve visited cutting-edge factory automation and observed industry policy aimed at structural transformation of manufacturing through digital technology — the so-called “Industry 4.0”. Particularly, systems for data linkage between factories and companies and governance design were very suggestive for thinking about future Japanese manufacturing.

In China we visited Shenzhen, sometimes called the “hardware Silicon Valley”, and through entrepreneurs, manufacturing sites, venture capital and accelerators we learned how ideas take shape and grow into business. Through these on-site visits we aim to understand the manufacturing ecosystem that supports innovation and apply that to the future industrial competitiveness of Japan.

Through this practical knowledge, we don’t just learn theory, but we can also understand management decision-making and organizational transformation approaches that are globally applicable. I feel that knowing best practices around the world is extremely important for Japanese companies confronting challenges, in order to relativize those challenges and explore the next direction of reform.

──You said students also participate in your research activities. Are there results on that front too?

Yes. Facing real challenges that companies face, presenting solutions to people at the front line of operations and receiving feedback — for students it is definitely a large gain. We go on study tours to factories, companies and academic institutes domestically and overseas, and prominent practitioners in this field occasionally drop by unannounced, so I believe the stimulation is significant.

Including that, creating a ‘learning ecosystem’ in the field of supply-chain and service-operations management is my goal. For the university: discovery of new research opportunities and growth of students; for industry: acquisition of the latest theory and securing talent; for students: meaningful learning opportunities and paths to career. If a structure that fulfils each of these needs can be made, that would be ideal.

As a result, I hope Japanese manufacturing will regain strength and once again take the lead in solving global issues.

Ultrafast Multivalley Optical Switching in Germanium for High-Speed Computing and Communications

Researchers demonstrate ultrafast transparency switching across multiple wavelengths using single laser excitation in germanium

Multicolored optical switching is essential for potential advancements in telecommunication and optical computing. However, most materials typically exhibit only single-colored optical nonlinearity under intense laser illumination. To address this, researchers have demonstrated that exciting the multivalley semiconductor germanium with a single-color pulse laser enables ultrafast transparency switching across multiple wavelengths. This breakthrough could drive the development of ultrafast optical switches for future multiband communication and optical computing.

Opaque materials can transmit light when excited by a high-intensity laser beam. This process, known as optical bleaching, induces a nonlinear effect that temporarily alters the properties of a material. Remarkably, when the laser is switched on and off at ultrahigh speeds, the effect can be dynamically controlled, opening new possibilities for advanced optical technologies.

Multicolored optical switching is an important phenomenon with potential applications in fields such as telecommunications and optical computing. However, most materials typically exhibit single-color optical nonlinearity under intense laser illumination, limiting their use in systems requiring multicolor or multiband switching capabilities. Currently, most optical switches are based on microelectromechanical systems, which require an electric voltage or current to operate, resulting in slow response times.

To address this gap, a group of researchers, led by Professor Junjun Jia from the Faculty of Science and Engineering at Waseda University, Japan, in collaboration with Professor Hui Ye and Dr. Hossam A. Almossalami from the College of Optical Science and Engineering at Zhejiang University, China, Professor Naoomi Yamada from the Department of Applied Chemistry at Chubu University, Japan, and Dr. Takashi Yagi from the National Institute of Advanced Industrial Science and Technology, Japan, investigated the multivalley optical switching phenomenon in germanium (Ge) films. They focused on how intense laser irradiation induces ultrafast optical switching across multiple wavelengths in Ge, a multivalley semiconductor. Their study demonstrated efficient multicolored optical switching using a single-color pulse laser, potentially overcoming the limitations of traditional single-color optical nonlinearities. Their research was published in Physical Review Applied on February 24, 2025.

By irradiating Ge with an intense pulse laser, the team achieved ultrafast switching between transparency and opacity across a wide wavelength range. Femtosecond time-resolved transient transmission measurements revealed ultrafast optical switching in both the Γ and L valleys, due to the existence of intravalley and intervalley scattering. “Our results confirm that intense laser irradiation in Ge films allows for ultrafast optical switching across multiple wavelengths, offering the possibility of controlling a material’s transparency and opening new doors for possible applications in optical communications, optical computing, and beyond,” explains Prof. Jia.

Such multivalley optical switching is found to strongly depend on the band structure of Ge. Experimental measurements suggest that the transient signal is highly dependent on the specific region of the band structure involved. For example, the transient transmission spectra reveal a split-off energy of 240 meV at the L high symmetric point. “Careful selection of probing energies, based on the band dispersion calculated with the HSE06 functional and spin-orbit coupling effects, allowed us to accurately capture the transient electronic occupation in both the Γ and L valleys,” says Prof. Jia. This allows the extraction of intervalley and intravalley scattering times in multivalley materials from transient measurements.

Overall, this study highlights the significant potential of Ge as a key material for advanced optical switching, with promising applications in high-speed data transmission and computing. By enabling control over transparency at multiple wavelengths using a single-color pulse laser, exciting possibilities open up for the development of ultrafast optical switches. “This finding is expected to address the growing demand for higher data rates and security in the face of increasing internet traffic, marking a key step forward in the advancement of ultrafast optical switching devices,” concludes Prof. Jia.

Reference

Authors: Junjun Jia¹, Hossam A. Almossalami², Hui Ye², Naoomi Yamada³, Takashi Yagi⁴
Title of original paper: Multivalley optical switching in germanium
Journal: Physical Review Applied
DOI: 10.1103/PhysRevApplied.23.024060
Article Publication Date:24 February 2025
Affiliations:
¹Global Center for Science and Engineering (GCSE), Faculty of Science and Engineering, Waseda University, Japan
²College of Optical Science and Engineering, Zhejiang University, China
³Department of Applied Chemistry, Chubu University, Japan
⁴National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Japan

About Professor Junjun Jia

Junjun Jia is a Professor at the Faculty of Science and Engineering, Waseda University, Japan. He earned his Ph.D. from the University of Tokyo in 2011. His research focuses on the design and fabrication of functional solid-state materials, as well as the development of solid-state devices, including solid-state thermal circuital elements, acoustic wave-based devices, and nonequilibrium electronic devices. His interests include nonlinear optics, non-equilibrium physics, and excited electronic/phonon structure in solids materials. Dr. Jia has published extensively in peer-reviewed journals such as Advanced Functional Materials, Physical Review B, Physical Review Applied. He has received several awards, including the Waseda e-Teaching Award in 2022. He is a member of various committees, including the Materials Research Society of Japan.

An Efficient Self-Assembly Process for Advanced Self-Healing Materials

The novel method produces multilayered self-healing films with enhanced durability compared to conventional materials for coatings and flexible electronics

Self-healing coatings are advanced materials that can repair damage, such as scratches and cracks on their own. Researchers from Waseda University have developed an efficient method for preparing self-healing films consisting of alternating layers of highly cross-linked organosiloxane and linear polydimethylsiloxane (PDMS). Their film is more durable than conventional self-healing PDMS materials, offering superior hardness and greater thermal stability while self-healing at mild temperatures, paving the way for stronger, more reliable, and easier-maintained self-healing materials.

Polysiloxane materials, such as polydimethylsiloxane (PDMS)-based elastomers, exhibit a self-healing capability by the introduction of silanolate (Si–O^–) groups. This ability stems from their dynamic siloxane (Si–O–Si) bonds, which can break and reform to repair damage. Their self-healing properties could make them valuable in applications like protective coatings for use in various fields, such as optics, electronics, and aerospace.

To improve the properties of PDMS-based materials, they have been combined with inorganic fillers such as nanoparticles or nanosheets. Generally, the introduction of nanosheets into polymers leads to the formation of a layered structure that exhibits superior thermal, mechanical, and gas barrier properties. Furthermore, improved crack healing ability of oriented films was reported. This improvement is attributed to polymer diffusion concentrated in the in-plane direction.

Researchers at Waseda University, Japan, have made significant progress in enhancing self-healing siloxane materials by developing a more efficient method for fabricating multilayered films. In a study published on January 6, 2025, in Volume 61, Issue 16, of the journal Chemical Communications, a team led by Professor Atsushi Shimojima, with Research Associate Yoshiaki Miyamoto and Assistant Professor Takamichi Matsuno, fabricated a composite film composed of highly cross-linked organosiloxane (silsesquioxane) and grafted PDMS layers using a self-assembly process.

“Replacing traditional materials with our self-healing material, which is less susceptible to deterioration and has high hardness, would be in high demand for maintenance-free and durable applications,” says Miyamoto, the lead author of the study.

The researchers began by depositing a solution containing 1,2-bis(triethoxysilyl)ethane, Pluronic P123 (a PEO–PPO–PEO triblock copolymer, where PEO stands for poly(ethylene oxide) and PPO stands for poly(propylene oxide)), and a PEO–PDMS–PEO block copolymer onto a silicon or glass substrate using spin-coating or drop-casting techniques. This process formed a thin film with a lamellar (layered) structure.

The film was then calcinated in air at 170 °C for 4 hours, resulting in the removal of the PEO and PPO blocks. This process left behind a multilayered structure composed of silsesquioxane and PDMS layers.

To impart self-healing properties to the film, Si–O^– groups were introduced. These groups promote rearrangement and reconnection of the siloxane (Si–O–Si) networks. To achieve this, the film was immersed in a solution of tetrahydrofuran, water, and potassium hydroxide (KOH). In this process, hydroxide ions (OH^–) from KOH removed protons (H⁺) from silanol (Si–OH) groups, converting them into Si–O^– ions. The final film could repair micrometer-scale cracks when heated to 80 °C at 40% relative humidity for 24 hours.

The film showed superior properties compared to conventional PDMS-based materials. The cross-linked organosiloxane layers provided greater rigidity and served as a barrier against the volatilization of cyclic siloxanes, addressing the limitations of traditional PDMS materials. While conventional self-healing PDMS elastomers have a hardness of 49 MPa, the final self-healing film exhibited a hardness of 1.50 GPa.

“This innovative multilayered design allows our material to be both harder and more heat-resistant than existing self-healing siloxane-based materials, paving the way for more durable and reliable applications,” says Miyamoto.

With its high hardness and self-healing properties, this material is well-suited for protective coatings, flexible electronics, and other applications that require long-lasting performance.

Reference

Title of original paper:Multilayered organosiloxane films with self-healing ability converted from block copolymer nanocomposites
DOI:10.1039/D4CC05804F
Journal:Chemical Communications
Article Publication Date:06 January 2025
Authors:Yoshiaki Miyamoto¹, Takamichi Matsuno^1,2,3 and Atsushi Shimojima^1,2,3
Affiliations:
¹Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Japan
²Waseda Research Institute for Science and Engineering, Waseda University, Japan
³Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, Japan

About Dr. Yoshiaki Miyamoto from Waseda University

Dr. Yoshiaki Miyamoto is a Research Associate at the School of Advanced Science and Engineering, working under the supervision of Professor Atsushi Shimojima. His research focuses on the relationship between material structure, composition, and self-healing properties, particularly within the realm of siloxane-based materials. He explores factors such as network flexibility, swelling behavior, and dynamic bond rearrangement. His research has produced publications demonstrating expertise in designing self-healing materials with improved mechanical properties and thermal and chemical stability. Dr. Miyamoto’s research contributes to the advancement of functional materials with potential applications in coatings, adhesives, and other areas where self-healing capabilities are crucial.

Machine Learning Unlocks Superior Performance in Light-Driven Organic Crystals

LASSO regression and Bayesian optimization enhance crystal force output, advancing next-generation light-responsive actuator materials

Researchers have developed a machine learning workflow to optimize the output force of photo-actuated organic crystals. Using LASSO regression to identify key molecular substructures and Bayesian optimization for efficient sampling, they achieved a maximum blocking force of 37.0 mN—73 times more efficient than conventional methods. These findings could help develop remote-controlled actuators for medical devices and robotics, supporting applications such as minimally invasive surgery and precision drug delivery.

Materials that convert external stimuli into mechanical motion, known as actuators, play a crucial role in robotics, medical devices, and other advanced applications. Among them, photomechanical crystals deform in response to light, making them promising for lightweight and remotely controllable actuation. Their performance depends on factors such as molecular structures, crystal properties, and experimental conditions.

A key performance indicator of these materials is the blocking force—the maximum force exerted when deformation is completely restricted. However, achieving high blocking forces remains challenging due to the complex interplay of crystal characteristics and testing conditions. Understanding and optimizing these factors is essential for expanding the potential applications of photomechanical crystals.

In a step toward optimizing the output force of photo-actuated organic crystals, researchers from Waseda University have leveraged machine learning techniques to enhance their performance. The study was led by Associate Professor Takuya Taniguchi from the Center for Data Science, along with Mr. Kazuki Ishizaki and Professor Toru Asahi, both from the Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering at Waseda University. Their findings were published online in Digital Discovery on 20 March 2025.

“We noticed that machine learning simplifies the search for optimal molecules and experimental parameters,” says Dr. Taniguchi. “This inspired us to integrate data science techniques with synthetic chemistry, enabling us to rapidly identify new molecular designs and experimental approaches for achieving high-performance results.”

In this study, the team utilized two machine learning techniques: LASSO (least absolute shrinkage and selection operator) regression for molecular design and Bayesian optimization for selecting experimental conditions. The first step led to a material pool of salicylideneamine derivatives, while the second enabled efficient sampling from this pool for real-world force measurements. As a result, the team successfully maximized the blocking force, achieving up to 3.7 times greater force output compared to previously reported values and accomplishing this at least 73 times more efficiently than conventional trial-and-error method.

“Our research marks a significant breakthrough in photo-actuated organic crystals by systematically applying machine learning,” says Dr. Taniguchi. “By optimizing both molecular structures and experimental conditions, we have demonstrated the potential to dramatically enhance the performance of light-responsive materials.”

The proposed technology has broad implications for remote-controlled actuators, small-scale robotics, medical devices, and energy-efficient systems. Because photo-actuated crystals respond to light, they enable contactless and remote operation, making them ideal robotic components working in confined or sensitive environments. Their ability to generate force noninvasively with focused light could also be valuable for microsurgical tools and drug delivery mechanisms that require precise, remote actuation.

By leveraging a cleaner energy input—light irradiation—while maximizing mechanical output, these materials hold promise for eco-friendly manufacturing processes and devices aimed at reducing overall energy consumption. “Beyond improving force output, our approach paves the way for more sophisticated, miniaturized devices, from wearable technology to aerospace engineering and remote environmental monitoring,” Dr. Taniguchi adds.

In conclusion, this study highlights the power of a machine learning–driven strategy in accelerating the development of high-performance photo-actuated materials, bringing them one step closer to real-world applications and commercial viability.

Reference

Authors: Kazuki Ishizaki¹, Toru Asahi¹, and Takuya Taniguchi²
Title of original paper: Machine Learning-Driven Optimization of Output Force in Photo-Actuated Organic Crystals
Journal: Digital Discovery
DOI:10.1039/D4DD00380B
Article Publication Date:20 March 2025
Affiliations:
¹Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University
²Center for Data Science, Waseda University

About Associate Professor Takuya Taniguchi from Waseda University

Takuya Taniguchi is an Associate Professor at the Center for Data Science at Waseda University, Japan. He received a Doctor of Engineering degree from the Department of Advanced Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, in 2019. His research areas of interest include structural organic chemistry, physical organic chemistry, organic functional materials, materials informatics, and materials science. His publications have received over 500 citations.

We’re proud to bring you Waseda Universty’s Research Recap 2024. The video highlights just a few of the many innovators who conducted influential research at our university over the past year. Watch for a peek at their diverse research covering everything from self-healing interconnects and airborne microplastics to conversational AI media systems and hydrogen storage materials.

If you wish to find out more about the extensive activities at our University, click on one of the links that follow in the description. Thanks to all the students and professors who put their research on display for this video.

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Associate Professor: TAKAHASHI, Ryo (Faculty of Political Science and Economics)

Research Theme: Economic development and environmental conservation in developing countries
Recent Research: https://www.waseda.jp/inst/research/news-en/76941
Researcher Details: https://w-rdb.waseda.jp/html/100001339_en.html
2022 WASEDA research acceleration program for early-stage principal investigators

Professor: TAKEZAWA, Akihiro (Faculty of Science and Engineering)

Research Theme: Development of additive manufactured functional structure
Recent Research: https://www.waseda.jp/inst/research/news-en/76856
Researcher Details: https://w-rdb.waseda.jp/html/100002014_en.html
The recipients of the 2022 Waseda Research Award

Professor: IWASE, Eiji (Faculty of Science and Engineering)

Research Theme: Micro-electro-mechanical systems
Recent Research: https://www.waseda.jp/inst/research/news-en/76980
Researcher Details: https://w-rdb.waseda.jp/html/100001156_en.html
The recipients of the 2016 Waseda Research Award
2023 Next-generation Core researcher

Associate Professor: ISHII, Ayumi (Faculty of Science and Engineering)

Research Theme: Inorganic materials chemistry
Recent Research: https://www.waseda.jp/inst/research/news-en/76941
Researcher Details: https://w-rdb.waseda.jp/html/100003644_en.html

Professor: YOO, Byung Kwang (Faculty of Human Sciences)

Research Theme: Public health, Infectious diseases, Health education
Recent Research: https://www.waseda.jp/inst/research/news-en/76882
Researcher Details: https://w-rdb.waseda.jp/html/100003620_en.html

Professor: OKOCHI, Hiroshi (Faculty of Science and Engineering)

Research Theme: Environmental Chemistry
Recent Research: https://www.waseda.jp/top/en/news/78501
Researcher Details:  https://w-rdb.waseda.jp/html/100000728_en.html

Assistant Professor: HANADA, Nobuko (Faculty of Science and Engineering)

Research Theme: Energy material science, chemical reaction and energy process engineering
Recent Research: https://www.waseda.jp/inst/research/news-en/76960
Researcher Details: https://w-rdb.waseda.jp/html/100001495_en.html

Associate Research Professor: MATSUYAMA, Yoichi (Green Computing Systems Research Organization)

Research Theme: Conversational AI media systems
Recent Research: https://www.waseda.jp/inst/research/news-en/76861
Researcher Details: https://www.yoichimatsuyama.com/about/

Associate Professor: HOSOKAWA, Yuri (Faculty of Sport Sciences)

Research Theme: Safety and performance optimization
Recent Research: https://www.waseda.jp/inst/research/news-en/76832
Researcher Details: https://w-rdb.waseda.jp/html/100001822_en.html

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Constructing a Deep Generative Approach for Functional RNA Design

A collaborative research effort by Professor Hirohide Saito (Department of Life Science Frontiers, CiRA, Kyoto University) and Professor Michiaki Hamada of Waseda University has developed the world’s first deep generative model for RNA design.

While antisense oligonucleotide and aptamer drugs have been on the market since the 2000s, it was not until the development of SARS-CoV2 mRNA vaccines employed to fight against the COVID-19 pandemic that RNA-based therapeutics attracted the attention of the general public.

In contrast, because of their immense potential—not only for medical applications but for basic biological research and biotechnology—RNA engineering has been on the scientific forefront for decades. As such, there is a tremendous interest in revolutionizing current approaches for designing RNA sequences. Remarkably, there is still no versatile computational platform for functional RNA design. Most existing approaches function by reconstructing specific secondary structures or are restricted to particular types of sequences, such as CRISPR gRNA, mRNA, or specific riboswitches. Since these traditional approaches typically depend on predicting and optimizing RNA secondary structures, their accuracy is inherently constrained by structural prediction and optimization algorithms. A novel approach was thus necessary to avoid these limitations and produce powerful and robust computational methods to construct RNA with desired functions.

The research team aimed to avoid these problems by focusing on RNA families, which are sequence groups with thousands of functional RNAs endowed with identical functions. Even with only a few hundred sequences, multiple sequence alignment can create a consensus secondary structure from which new sequences can be generated. As this computational platform theoretically works with any functional RNA families, the researchers named their deep generative model the RNA family sequence Generator, or RfamGen, which is the world’s first deep generative model for functional RNA design.

RfamGen combines two approaches: (1) covariance model and (2) variational autoencoder. The covariance model is a type of statistical framework for RNA alignment and consensus secondary structure that quantitatively evaluates variations of sequence and structure. Meanwhile, the variational autoencoder is a deep generative model with an internal representation called “latent space” to mitigate the complexity associated with exploring the exponentially vast sequence space for the optimization of RNA sequences. By leveraging these two concepts, the researchers generated a system that learns sequence and structural information to explore new RNA designs logically, a feat that has never been done previously.

The team first compared RfamGen, which considers both alignment and secondary structural information, with models accounting for either alignment or secondary structural information, or neither.

For the 18 RNA families tested (each with alignments comprised of at least 10,000 sequences), RfamGen showed a significantly improved ability to generate high-quality RNA sequences. Furthermore, the researchers also tested RfamGen’s capabilities when restricted to a limited number of input sequences from which to learn. Despite only being trained on 500 input sequences, RfamGen successfully generated RNA sequences with high scores, thus demonstrating its efficient generative capacity.

The researchers next trained RfamGen using 629 RNA families in total, each with at least 100 sequences from the Rfam database, and found RfamGen performs substantially better compared to other systems. The researchers, furthermore, evaluated how well generated RNA sequences function by randomly synthesizing several RNA sequences generated from training it with a diversity of self-cleavage ribozymes and from random sampling a covariance model. Notably, the sequences generated by RfamGen showed enzymatic activity, while the randomly sampled sequences did not, indicating RfamGen learned important features essential for functionality from the training data.

Lastly, the research team utilized the ligand-dependent self-cleavage activity of the glmS ribozyme as a comparative platform to benchmark generated sequences by RfamGen to natural glmS sequences. They first trained RfamGen using about 500 natural glmS ribozyme sequences and sampled the “latent space” to obtain 1,000 generated sequences. Using a massively parallel assay, they tested these 1,000 generated sequences, 761 natural sequences in the glmS ribozyme family (RF00234), and 100 sequences with kinetic measurements from a previous report. Not only did the team observe the generated sequences to possess a similar distribution of cleavage kinetics as natural sequences, but remarkably found that generated sequences showed higher cleavage rates compared to natural sequences, thus suggesting RfamGen successfully generates high-quality sequences with comparable or higher efficiency than some natural sequences.

The golden age of RNA-based bioengineering is on the horizon. By constructing this deep generative model for functional RNA design, the research team believes RfamGen will be a fundamental driving force to propel RNA biology into a new era and enable discoveries and applications based on RNA.

Paper Details

Journal:

Nature Methods

Title:

Deep generative design of RNA family sequences

Authors:

Shunsuke Sumi^1,2,3, Michiaki Hamada^3,4,5,*, Hirohide Saito^1,*
* : Corresponding authors

Author Affiliations:

1. Center for iPS Cell Research and Application (CiRA), Kyoto University
2. Graduate School of Medicine, Kyoto University
3. Graduate School of Advanced Science and Engineering, Waseda University
4. Computational Bio Big-Data Open Innovation Laboratory (CBBD-OIL), National Institute of Advanced Industrial Science and Technology (AIST)
5. Graduate School of Medicine, Nippon Medical School

doi:

https://doi.org/10.1038/s41952-023-02148-8

Discovery of Structural Regularity Hidden in Silica Glass

Glass – whether used to insulate our homes or as the screens in our computers and smartphones – is a fundamental material. Yet, despite its long usage throughout human history, the disordered structure of its atomic configuration still baffles scientists, making understanding and controlling its structural nature challenging. It also makes it difficult to design efficient functional materials made from glass.

To uncover more about the structural regularity hidden in glassy materials, a research group has focused on ring shapes in the chemically bonded networks of glass. The group, which included Professor Motoki Shiga from Tohoku University’s Unprecedented-scale Data Analytics Center, and Professor Akihiko Hirata from Waseda University created new ways in which to quantify the rings’ three-dimensional structure and structural symmetries: “roundness” and “roughness.”

Using these indicators enabled the group to determine the exact number of representative ring shapes in crystalline and glassy silica (SiO₂), finding a mixture of rings unique to glass and ones that resembled the rings in the crystals.

Additionally, the researchers developed a technique to measure the spatial atomic densities around rings by determining the direction of each ring.

They revealed that there is anisotropy around the ring, i.e., that the regulation of the atomic configuration is not uniform in all directions, and that the structural ordering related to the ring-originated anisotropy is consistent with experimental evidence, like the diffraction data of SiO₂. It was also revealed that there were specific areas where the atomic arrangement followed some degree of order or regularity, even though it appeared to be a discorded and chaotic arrangement of atoms in glassy silica.

“The structural unit and structural order beyond the chemical bond had long been assumed through experimental observations but its identification has eluded scientists until now,” says Shiga. “Furthermore, our successful analysis contributes to understanding phase-transitions, such as vitrification and crystallization of materials, and provides the mathematical descriptions necessary for controlling material structures and material properties.”

Looking ahead, Shiga and his colleagues will use these techniques to come up with procedures for exploring glass materials, procedures that are based on data-driven approaches like machine learning and AI.

Their findings were published open access in the journal Communication Materials on November 3, 2023.

<Publication Details>

Title: Ring-originated anisotropy of local structural ordering in amorphous and crystalline silicon dioxide
Authors: Motoki Shiga, Akihiko Hirata, Yohei Onodera, and Hirokazu Masai
Journal: Communications Materials
DOI: 10.1038/s43246-023-00416-w

Understanding the Dynamic Behavior of Rubber Materials

Researchers present a novel experimental system for simultaneous measurement of dynamic mechanical properties and X-ray computed tomography

Rubber-like materials can exhibit both spring-like and flow-like behaviors simultaneously, which contributes to their exceptional damping abilities. To understand the dynamic viscoelasticity of these materials, researchers from Japan have recently developed a novel system that can conduct dynamic mechanical analysis and dynamic micro X-ray computed tomography simultaneously. This technology can enhance our understanding of the microstructure of viscoelastic materials and pave the way for the development of better materials.

Rubber-like materials, commonly used in dampeners, possess a unique property known as dynamic viscoelasticity, enabling them to convert mechanical energy from vibrations into heat while exhibiting spring-like and flow-like behaviors simultaneously. Customization of these materials is possible by blending them with compounds of specific molecular structures, depending on the dynamic viscosity requirements.

However, the underlying mechanisms behind the distinct mechanical properties of these materials remain unclear. A primary reason for this knowledge gap has been the absence of a comprehensive system capable of simultaneously measuring the mechanical properties and observing the microstructural dynamics of these materials. While X-ray computed tomography (CT) has recently emerged as a promising option for a non-destructive inspection of the internal structure of materials down to nano-scale resolutions, it is not suited for observation under dynamic conditions.

Against this backdrop, a team of researchers, led by Associate Professor (tenure-track) Masami Matsubara from the School of Creative Science and Engineering at the Faculty of Engineering at Waseda University in Japan, has now developed an innovative system that can conduct dynamic mechanical analysis and dynamic micro X-ray CT imaging simultaneously. Their study was made available online on October 19, 2023 and will be published in Volume 205 of the journal Mechanical Systems and Signal Processing on December 15, 2023.

“By integrating X-ray CT imaging performed at the large synchrotron radiation facility Spring-8(BL20XU) and mechanical analysis under dynamic conditions, we can elucidate the relationship between a material’s internal structure, its dynamic behavior, and its damping properties,” explains Dr. Matsubara. At the core of this novel system is the dynamic micro X-ray CT and a specially designed compact shaker developed by the team that is capable of precise adjustment of vibration amplitude and frequency.

The team utilized this innovative system to investigate the distinctions between styrene-butadiene rubber (SBR) and natural rubber (NR), as well as to explore how the shape and size of ZnO particles influence the dynamic behavior of SBR composites.

The researchers conducted dynamic micro X-ray CT scans on these materials, rotating them during imaging while simultaneously subjecting them to vibrations from the shaker. They then developed histograms of local strain amplitudes by utilizing the local strains extracted from the 3D reconstructed images of the materials’ internal structures. These histograms, in conjunction with the materials’ loss factor, a measure of the inherent damping of a material, were analyzed to understand their dynamic behavior.

When comparing materials SBR and NR, which have significantly different loss factors, the team found no discernible differences between their local strain amplitude histograms. However, the histograms displayed wider strain distributions in the presence of composite particles like ZnO. This suggests that strain within these materials is non-uniform and depends on the shape and size of the particles, which may have masked any changes from the addition of the particles.

“This technology can allow us to study the microstructure of rubber and rubber-like materials under dynamic conditions and can result in the development of fuel-efficient rubber tires or gloves that do not deteriorate. Moreover, this technology can also enable the dynamic X-ray CT imaging of living organs that repeatedly deform, such as the heart, and can even pave the way for the development of artificial organs,” says Dr. Matsubara, highlighting the importance of this study.

Overall, this breakthrough technology has the potential to advance the understanding of the microstructure of viscoelastic materials, likely opening the doors for the development of novel materials with improved properties.

Reference

Authors	Masami Matsubara1, Ryo Takara2, Taichi Komatsu2, Shogo Furuta2, Khoo Pei Loon2, Masakazu Kobayashi2, Hitomu Mushiaki3, Kentaro Uesugi4, Shozo Kawamura2, and Daiki Tajiri2
Title of original paper	In-situ measurement of dynamic micro X-ray CT and dynamic mechanical analysis for rubber materials
Journal	Mechanical Systems and Signal Processing
DOI	10.1016/j.ymssp.2023.110875
Affiliations	1Department of Modern Mechanical Engineering, Waseda University 2Department of Mechanical Engineering, Toyohashi University of Technology 3Hyogo Prefectural Institute of Technology 4Japan Synchrotron Radiation Research Institute

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Associate Professor Masami Matsubara

Masami Matsubara is an Associate Professor (tenure-track) at the School of Creative Science and Engineering of the Faculty of Science and Engineering at Waseda University, Japan. He earned his Ph.D. from Doshisha University. His research focuses on the mechanics of materials, mechatronics, and dynamic modelling. He has recently worked on vibration reduction methods and dynamic design for large-scale numerical analysis models and detailed design and experimental methods for component and unit testing. He is a member of the Japan Society of Mechanical Engineers (JSME) and SAE International. He received the JSME Medal for Outstanding Paper in 2014, 2020, and 2022.

Direct Power Generation from Methylcyclohexane Using Solid Oxide Fuel Cells

Researchers have successfully generated electricity directly from methylcyclohexane, an organic hydride, using solid oxide fuel cells, with lower energy than conventional catalytic dehydrogenation reactions.

Methylcyclohexane is very promising as a hydrogen carrier that can safely and efficiently transport and store hydrogen. However, the dehydrogenation process using catalysts has issues due to its durability and large energy loss. Recently, Japanese researchers have succeeded in using solid oxide fuel cells to generate electricity directly from methylcyclohexane and recover toluene for reuse. This research is expected to not only reduce energy requirements but also explore new chemical synthesis by fuel cells.

Methylcyclohexane (MCH), a type of organic hydride, is expected to be an excellent hydrogen carrier because it remains liquid at room temperature, is easy to transport, has low toxicity, and has a higher hydrogen density than high-pressure hydrogen. Dehydrogenation—the process of removing hydrogen atoms from molecules—in the presence of a catalyst, yields hydrogen and the byproduct toluene, which can then be used to generate electricity to produce CO2-free power. However, the dehydrogenation reaction is an endothermic reaction, and energy loss as well as the facilities required for the reaction are issues.

Recently, a team of researchers from Japan, led by Professor Akihiko Fukunaga from the Department of Applied Chemistry at Waseda University, has succeeded in generating electricity directly from MCH using solid oxide fuel cells (SOFC). Their work was made available online on July 4, 2023 in Volume 348 of Applied Energy.

The research team tried to perform two processes simultaneously in a fuel cell: dehydrogenation from organic hydrides, which is an endothermic reaction, and electricity generation, which is an exothermic reaction. To achieve this, they used an anode-supported solid oxide fuel cell with a higher operating temperature than that of a polymer electrolyte fuel cell. They operated it at a temperature that did not allow pyrolysis of organic hydrides and under conditions that prevented carbon deposition at the electrodes. The production ratio of toluene to benzene was 94:6. This achievement demonstrated the possibility of generating electricity without using dehydrogenation facilities which were conventionally required and using less energy than that required for dehydrogenation reactions using catalysts.
In addition, “It was elucidated that by changing the conditions, oxygen groups could be introduced into the aromatic skeleton using a fuel cell” reveals Fukunaga.

These results indicate that the MHC reacts with the conducting oxygen ions in the SOFC to successfully generate electricity. Thus, power can be generated directly from MHC, and the energy required for direct power generation is lesser than that required for the conventional catalyst-assisted dehydrogenation reaction of MCH.

“Fuel cells have been studied and developed as devices that produce highly efficient, carbon-free electricity through the electrochemical reaction of hydrogen and oxygen. In this study, we have demonstrated that this device can be applied to control dehydrogenation reactions from organic hydrides and oxygen substitution reactions of aromatic rings. In the future, new synthetic chemistry may be created by applying fuel cells.” concludes Fukunaga. Here’s hoping that the proposed technology will pave the way to a sustainable hydrogen-based society!

Reference

Authors

Akihiko Fukunaga¹, Asami Kato¹, Yuki Hara¹, and Takaya Matsumoto

Title of original paper

Dehydrogenation of Methylcyclohexane Using Solid Oxide Fuel Cell – A Smart Energy Conversion

Journal

Applied Energy

DOI

10.1016/j.apenergy.2023.121469

Affiliations

¹ Department of Applied Chemistry, Waseda University

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Professor Akihiko Fukunaga

Dr. Akihiko Fukunaga is a Faculty of Science and Engineering at the School of Advanced Science and Engineering at Waseda University in Japan. He received his Ph.D. from Waseda University in 1999 and has been a Professor of Applied Chemistry there since 2019. Prior to that, he worked at JXTG Nippon Oil & Energy Corporation from 1984 to 2019, where he successfully commercialized the residential fuel cell system, EneFarm. His research interests include energy materials, hydrogen, fuel cells, and carbon recycling.

A Novel, Completely Solid, Rechargeable Air Battery

 A benzoquinone-based negative electrode and solid Nafion polymer electrolyte are used in this first-of-its-kind battery

Solid-state batteries use solid electrodes and solid electrolytes, unlike the more commonly known lithium-ion batteries, which use liquid electrolytes. Solid-state batteries overcome various challenges associated with liquid-based batteries, such as flammability, limited voltage, unstable reactants, and poor long-term cyclability and strength. Making advances in this field, researchers recently demonstrated an all-solid-state rechargeable air battery composed of a redox-active organic negative electrode and a proton-conductive polymer electrolyte.

Metals are typically used as active materials for negative electrodes in batteries. Recently, redox-active organic molecules, such as quinone- and amine-based molecules, have been used as negative electrodes in rechargeable metal–air batteries with oxygen-reducing positive electrodes. Here, protons and hydroxide ions participate in the redox reactions. Such batteries exhibit high performance, close to the maximum capacity that is theoretically possible. Furthermore, using redox-active organic molecules in rechargeable air batteries overcomes problems associated with metals, including the formation of structures called ‘dendrites,’ which impact battery performance, and have negative environmental impact. However, these batteries use liquid electrolytes—just like metal-based batteries—which pose major safety concerns like high electrical resistance, leaching effects, and flammability.

Now, in a new study published in Angewandte Chemie International Edition on May 2, 2023, a group of Japanese researchers have developed an all-solid-state rechargeable air battery (SSAB) and investigated its capacity and durability. The study was led by Professor Kenji Miyatake from Waseda University and the University of Yamanashi, and co-authored by Professor Kenichi Oyaizu from Waseda University.

The researchers chose a chemical called 2,5-dihydroxy-1,4-benzoquinone (DHBQ) and its polymer poly(2,5-dihydroxy-1,4-benzoquinone-3,6-methylene) (PDBM) as active materials for the negative electrode due to their stable and reversible redox reactions in acidic conditions. In addition, they utilized a proton-conductive polymer called Nafion as the solid electrolyte, thereby replacing conventional liquid electrolytes. “To the best of my knowledge, no air batteries based on organic electrodes and solid polymer electrolyte have been developed yet,” says Miyatake.

After the SSAB was in place, the researchers experimentally assessed its charge–discharge performance, rate characteristics, and cyclability. They found that unlike typical air batteries that use a metallic negative electrode and an organic liquid electrolyte, the SSAB did not deteriorate in the presence of water and oxygen. Furthermore, replacing the redox-active molecule DHBQ with its polymeric counterpart PDBM formed a better negative electrode. While the per gram-discharge capacity of the SSAB-DHBQ was 29.7 mAh, the corresponding value of the SSAB-PDBM was 176.1 mAh, at a constant current density of 1 mAcm^-2.

The researchers also found that the coulombic efficiency of SSAB-PDBM was 84% at 4 C rate, which gradually decreased to 66% at 101 C rate. While the discharge capacity of SSAB-PDBM reduced to 44% after 30 cycles, by increasing the proton-conductive polymer content of the negative electrode, the researchers could significantly improve it to 78%. Electron microscopic images confirmed that the addition of Nafion improved the performance and durability of the PDBM-based electrode.

This study demonstrates the successful operation of an SSAB comprising redox-active organic molecules as the negative electrode, a proton-conductive polymer as the solid electrolyte, and an oxygen-reducing, diffusion type positive electrode. The researchers hope that it will pave the way for further advancements. “This technology can extend the battery life of small electronic gadgets such as smartphones and eventually contribute to realizing a carbon-free society,” concludes Miyatake.

Reference

Authors

Makoto Yonenaga¹, Yusuke Kaiwa², Kouki Oka^2,3, Kenichi Oyaizu², and Kenji Miyatake¹

Title of original paper

All-Solid-State Rechargeable Air Batteries Using Dihydroxybenzoquinone and Its Polymer as the Negative Electrode

Journal

Angewandte Chemie International Edition

DOI

10.1002/anie.202304366

Affiliations

¹Clean Energy research Center, Fuel Cell Nanomaterials Center, University of Yamanashi
²Department of Applied Chemistry, Research Institute for Science and Engineering, Waseda University
³Center for Future Innovation (CFI) and Department of Applied Chemistry, Graduate School of Engineering, Osaka University

Funding Information

This work was partly supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, through Grants-in-Aid for Scientific Research (18H05515, 23H02058), MEXT Program: Data Creation and Utilization Type Material Research and Development Project (JPMXP1122712807), and JKA promotion funds from AUTORACE.

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Professor Kenji Miyatake

Kenji Miyatake received his Ph.D. degree in chemistry from Waseda University in 1996. He was a Japan Society for the Promotion of Science (JSPS) postdoctoral fellow at McGill University from 1999 to 2001. In 2001, he was offered an associate professor position at the Clean Energy Research Center at the University of Yamanashi, where he currently serves as a professor. He also holds a professor position in his alma mater since 2020. He is also a Fellow of the Royal Society of Chemistry.

 

Novel, Highly Sensitive Biosensor Set to Transform Wearable Health Monitoring

Researchers from Japan have developed a new wearable biosensor that can detect extremely small changes in tear glucose and blood lactate levels

Wearable wireless biosensors are an integral part of digital healthcare and monitoring. Commonly used chipless resonant antenna-based biosensors are simple and affordable, but have limited applicability due to their low sensitivity. Now, researchers from Japan have developed a novel, wireless, parity–time symmetry-based bioresonator that can detect minute concentrations of tear glucose and blood lactate. This highly sensitive, tunable, and robust bioresonator has the potential to revolutionize personalized health monitoring and digitized healthcare systems.

Researchers have developed a novel, wireless, PT-symmetric wearable resonator that can detect tear glucose and blood lactate levels in the micromolar range. The resonator is composed of an inductance–capacitance–resistance (LCR) reader and an LCR sensor with an enzyme-based chemiresistor. The setup has a high quality (Q) factor, making it highly sensitive.

Wireless wearable biosensors have been a game changer in personalized health monitoring and healthcare digitization because they can efficiently detect, record, and monitor medically significant biological signals. Chipless resonant antennae are highly promising components of wearable biosensors, as they are affordable and tractable. However, their practical applications are limited by low sensitivity (inability to detect small biological signals) caused by low quality (Q) factor of the system.

To overcome this hurdle, researchers led by Professor Takeo Miyake from Waseda University, Professor Yin Sijie from Beijing Institute of Technology, and Taiki Takamatsu from Japan Aerospace Exploration Agency, have developed a wireless bioresonator using “parity–time (PT) symmetry” that can detect minute biological signals. Their work has been published in Advanced Materials Technologies.

In this study, the researchers designed a bioresonator consisting of a magnetically coupled reader and sensor with high Q factor, and thus, increased sensitivity to biochemical changes. The reader and sensor both comprise an inductor (L) and capacitor (C) that are parallel-connected to a resistor (R). In the sensor, the resistor is a chemical sensor called a “chemiresistor” that converts biochemical signals into changes in resistance. The chemiresistor contains an enzymatic electrode with an immobilized enzyme. Minute biochemical changes at the enzymatic electrode (in response to changes in the levels of biomolecules such as blood sugar or lactate) are thus converted into electrical signals by the sensor, and then amplified at the reader.

Explaining the technical concept behind their novel biosensor, Miyake says, “We modeled the characteristics of the PT-symmetric wireless sensing system by using an eigenvalue solution and input impedance, and experimentally demonstrated the sensitivity enhancement at/near the exceptional point by using parallel inductance–capacitance–resistance (LCR) resonators. The developed amplitude modulation-based PT-symmetric bioresonator can detect small biological signals that have been difficult to measure wirelessly until now. Moreover, our PT-symmetric system provides two types of readout modes: threshold-based switching and enhanced linear detection. Different readout modes can be used for different sensing ranges.”

The researchers tested the system (here containing a glucose-specific enzyme) on human tear fluids and found that it could detect glucose concentrations ranging from 0.1 to 0.6 mM. They also tested it with a lactate-specific enzyme and commercially available human skin and found that it could measure lactate levels in the range of 0.0 to 4.0 mM through human skin tissue, without any loss of sensitivity. This result further indicates that the biosensor can be used as an implantable device. Compared to a conventional chipless resonant antenna-based system, the PT-symmetric system achieved a 2000-fold higher sensitivity in linear and a 78% relative change in threshold-based detection respectively.

Sharing his vision for the future, Miyake concludes, “The present telemetry system is robust and tunable. It can enhance the sensitivity of sensors to small biological signals. We envision that this technology can be used for developing smart contact lenses to detect tear glucose and/or implantable medical devices to detect lactate for efficient monitoring of diabetes and blood poisoning.”

This novel PT-symmetric wireless wearable bioresonator may soon usher in a new era of personalized health monitoring and efficient digitized healthcare systems!

Reference

Title of original paper: Wearable, Implantable, Parity-Time Symmetric Bioresonators for Extremely Small Biological Signal Monitoring
DOI: 10.1002/admt.202201704
Journal: Advanced Materials Technologies
Article Publication Date: 08 April 2023
Authors: Taiki Takamatsu¹, Yin Sijie¹, Takeo Miyake^1,2
Affiliations:
¹ Faculty of Science and Engineering, Graduate School of Information, Production and Systems, Waseda University, Japan
² PRESTO, Japan Science and Technology Agency, Japan

A Sowing, Pruning, and Harvesting Robot for Synecoculture^TM Farming

Researchers develop a four-wheeled, two orthogonal axes mechanism robot to maintain plants grown under solar panels

Synecoculture, a new farming method, involves growing mixed plant species together in high density. However, it requires complex operation since varying species with different growing seasons and growing speeds are planted on the same land. To address this need, researchers have developed a robot that can sow, prune, and harvest plants in dense vegetation grown. Its small, flexible body will help large-scale Synecoculture. This is an important step towards achieving sustainable farming and carbon neutrality.

Synecoculture is a new agricultural method advocated by Dr. Masatoshi Funabashi, senior researcher at Sony Computer Science Laboratories, Inc. (Sony CSL), in which various kinds of plants are mixed and grown in high density, establishing rich biodiversity while benefiting from the self-organizing ability of the ecosystem. However, such dense vegetation requires frequent upkeep—seeds need to be sown, weeds need to be pruned, and crops need to be harvested. Synecoculture thus requires a high level of ecological literacy and complex decision-making. And while the operational issues present with Synecoculture can be addressed by using an agricultural robot, most existing robots can only automate one of the above three tasks in a simple farmland environment, thus falling short of the literacy and decision-making skills required of them to perform Synecoculture. Moreover, the robots may make unnecessary contact with the plants and damage them, affecting their growth and the harvest.

With the rising awareness of environmental issues, such a gap between the performance of humans versus that of conventional robots has spurred innovation to improve the latter.

A group of researchers led by Takuya Otani, an Assistant Professor at Waseda University, in collaboration with Sustainergy Company and Sony CSL, have designed a new robot that can perform Synecoculture effectively. The robot is called SynRobo, with “syn” conveying the meaning of “together with” humans. It manages a variety of mixed plants grown in the shade of solar panels, an otherwise unutilized space. An article describing their research was published in Volume 13, Issue 1 of Agriculture, on 21 December 2022. This article has been co-authored by Professor Atsuo Takanishi, also from Waseda University, other researchers of Sony CSL, and students from Waseda University.

Otani briefly explains the novel robot’s design. “It has a four-wheel mechanism that enables movement on uneven land and a robotic arm that expands and contracts to help overcome obstacles. The robot can move on slopes and avoid small steps. The system also utilizes a 360^o camera to recognize and maneuver its surroundings. In addition, it is loaded with various farming tools—anchors (for punching holes), pruning scissors, and harvesting setups. The robot adjusts its position using the robotic arm and an orthogonal axes table that can move horizontally.”  

Besides these inherent features, the researchers also invented techniques for efficient seeding. They coated seeds from different plants with soil to make equally-sized balls. These made their shape and size consistent, so that the robot could easily sow seeds from multiple plants. Furthermore, an easy-to-use, human-controlled maneuvering system was developed to facilitate the robot’s functionality. The system helps it operate tools, implement automatic sowing, and switch tasks.

The new robot could successfully sow, prune, and harvest in dense vegetation, making minimal contact with the environment during the tasks because of its small and flexible body. In addition, the new maneuvering system enabled the robot to avoid obstacles 50% better while reducing its operating time by 49%, compared to a simple controller.

“This research has developed an agricultural robot that works in environments where multiple species of plants grow in dense mixtures,” Otani tells us. “It can be widely used in general agriculture as well as Synecoculture—only the tools need to be changed when working with different plants. This robot will contribute to improving the yield per unit area and increase farming efficiency. Moreover, its agricultural operation data will help automate the maneuvering system. As a result, robots could assist agriculture in a plethora of environments. In fact, Sustainergy Company is currently preparing to commercialize this innovation in abandoned fields in Japan and desertified areas in Kenya, among other places.”

Such advancements will promote Synecoculture farming, with the combination of renewable energy, and help solve various pressing problems, including climate change and the energy crisis. The present research is a crucial step toward achieving sustainable agriculture and carbon neutrality. Here’s hoping for a smart and skillful robot that efficiently supports large-scale Synecoculture!

Reference

Authors: Takuya Otani¹, Akira Itoh², Hideki Mizukami², Masatsugu Murakami², Shunya Yoshida², Kota Terae², Taiga Tanaka², Koki Masaya², Shuntaro Aotake^2,3, Masatoshi Funabashi³, and Atsuo Takanishi²

Title of original paper: Agricultural Robot under Solar Panels for Sowing, Pruning, and Harvesting in a Synecoculture Environment

Journal: Agriculture

DOI: 10.3390/agriculture13010018

Affiliations: 1: Waseda Research Institute for Science and Engineering, Waseda University, 2: Faculty of Science and Engineering, Waseda University, 3: Sony Computer Science Laboratories, Inc., Tokyo

About Professor Takuya Otani from Waseda Research Institute for Science and Engineering

Takuya Otani is an Assistant Professor at the Faculty of Science and Engineering at Waseda Research Institute for Science and Engineering. He received his Ph.D. degree from Waseda University in 2016. He is a member of the Virtual Reality Society of Japan, Japanese Council of IFToMM, Japan Society of Mechanical Engineers, Robotics Society of Japan, and IEEE. He received the Waseda e-Teaching Good Practice Award in 2021. His research interests include robotics and intelligent system, intelligent robotics, haptics, humanoid robotics, and mechanics and mechatronics. His recent work involves developing efficient robots for Synecoculture agriculture.

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Synecoculture

Synecoculture is a method of farming that produces useful plants while making multifaceted use of the self-organizing ability of the earth’s ecosystem. Advocated by Dr. Masatoshi Funabashi of Sony Computer Science Laboratories, Inc., it is characterized by a comprehensive ecosystem utilization method that considers not only food production but also the impacts on the environment and health.

*”Synecoculture” is a registered trademark or a trademark of Sony Group Corporation.

About Sustainergy Company

Sustainergy Company, a Tokyo-based renewable-energy startup, its management philosophy is “making the world sustainable through energy”, has been developing and operating solar power generation projects in Japan, including large-scale farm-based solar power generation (Agrivoltaics). The company noticed that the space under the solar panels of many solar power plants is underutilized and thought that if Sony CSL’s Synecoculture farming method could be applied to the semi-shaded area under the solar panels, the degraded soil could be restored, and the land could be turned into greenery and farmland, thereby enabling both food production and renewable energy production on the same land. Sustainergy Company is preparing to commercialize this project in abandoned farmlands in Japan, desertified areas in Kenya, and other countries. To learn more about Sustainergy Company, visit https://sustainergy.co.jp/.

Researchers successfully record the phase distribution of electrons, unveiling the detailed structure of its complex wavefunction

The structure, dynamics, and functions of materials are predominantly determined by their constituent electrons. Owing to their quantum nature, electrons have “wave”-like characteristics. However, measuring the phase of an electron and its complex electron wavefunction is challenging. Using state-of-the-art attosecond technology, researchers at Waseda University and National Research Council of Canada have now successfully recorded the phase distribution of electrons ejected from a neon atom, allowing a complete, detailed visualization of the complex electron wavefunction.

The early 20^th century saw the advent of quantum mechanics to describe the properties of small particles, such as electrons or atoms. Schrödinger’s equation in quantum mechanics can successfully predict the electronic structure of atoms or molecules. However, the “duality” of matter, referring to the dual “particle” and “wave” nature of electrons, remained a controversial issue. Physicists use a complex wavefunction to represent the wave nature of an electron. “Complex” numbers are those that have both “real” and “imaginary” parts—the ratio of which is referred to as the “phase”. However, all directly measurable quantities must be “real”. This leads to the following challenge: when the electron hits a detector, the “complex” phase information of the wavefunction disappears, leaving only the square of the amplitude of the wavefunction (a “real” value) to be recorded. This means that electrons are detected only as particles, which makes it difficult to explain their dual properties in atoms.

The ensuing century witnessed a new, evolving era of physics, namely, attosecond physics. The attosecond is a very short time scale, a billionth of a billionth of a second. “Attosecond physics opens a way to measure the phase of electrons. Achieving attosecond time-resolution, electron dynamics can be observed while freezing molecular motion,” explains Professor Hiromichi Niikura from the Department of Applied Physics, Waseda University, Japan, who, along with Professor D. M. Villeneuve—a principal research scientist at the Joint Attosecond Science Laboratory, National Research Council, and adjunct professor at University of Ottawa—pioneered the field of attosecond physics. Niikura and Villeneuve had previously developed a breakthrough method, attosecond re-collision, and also demonstrated the imaging of a molecular orbital or electron wavefunction in a molecule.

In a recent study published in Volume 106 Issue 6 (2022; page 063513) of Physical Review A on 23 December, 2022, these researchers employed another approach involving attosecond physics, using an attosecond laser pulse, or high-harmonic generation, to visualize a complex wavefunction. The attosecond laser pulse consists of coherent light with a wavelength much shorter than ultra-violet, referred to as extreme ultra-violet (EUV) light. When this pulse irradiates a gas, an electron is ejected. This process is referred to as photoionization. The attosecond pulse consists of a set of “harmonics” or different colors of light. By controlling the generation of the attosecond pulse, the researchers isolated two photoionization pathways—one consisting of a particular harmonic, and the other consisting of another harmonic along with an infrared pulse—to ionize neon. The electron wavefunctions produced by both pathways can interfere with each other. The interference pattern varies with the attosecond delay between the harmonics and the IR pulses. The team determined the phase and amplitude distributions of the photoelectron from the interference pattern and visualized its complex wavefunction. As the energy resolution is smaller than the bandwidth of the attosecond pulses, the researchers were successful in visualizing the detailed wavefunction structure. Furthermore, the researchers developed a method of disentangling the measured wavefunction into wavefunctions that are produced by individual ionization pathways.

Now that the researchers have successfully visualized the complex wavefunction of an electron—something that cannot be seen through conventional photoelectron spectroscopy—there’s so much more they can achieve! Niikura says, “Nowadays, photoelectron spectroscopy using EUV and X-ray has become a basic tool for investigating structures and dynamics of materials. The present method will provide a way to elucidate the quantum properties of electrons.” Visualizing the complete, detailed, complex electron wavefunction will be of significant impact in the fields of nanotechnology, chemistry, and molecular biology.

Reference

Authors: Takashi Nakajima¹, Tasuku Shinoda¹, D. M. Villeneuve² and Hiromichi Niikura¹
Title of original paper: High-resolution attosecond imaging of an atomic electron wavefunction in momentum space
Journal: Physical Review A
DOI: 10.1103/PhysRevA.106.063513
Latest Article Publication Date: 23 December, 2022
Affiliations: ¹Department of Applied Physics, Waseda University, Japan
²Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ontario, Canada

Image

Image title: Visualizing complex photoelectron wavefunctions using attosecond imaging technology
Image caption: Researchers measure the phase and amplitude of the complex electron wavefunctions (a,b), represented by color (or hue) for phase and brightness (or value) for amplitude (plotted in logarithmic scale), in the hue-saturation-value (HSV) color map, as shown in (c).
Image credits: Hiromichi Niikura from Waseda University
License type: Original content

About Professor Hiromichi Niikura from Waseda University

Hiromichi Niikura is a Professor at the Department of Applied Physics, Waseda University. He obtained his bachelors from Kyoto Institute of Technology, masters from Graduate School of Kyoto Institute of Technology, and Ph.D. from Graduate University for Advanced Studies, Institute for Molecular Science, Japan. His research focuses on atomic, molecular, and optical (AMO) physics. He has worked at National Research Council of Canada (2000-2009), where he conducted a pioneering work in attosecond physics, a new emerging field. Niikura was awarded the prestigious Japan Society for Promotion of Science (JSPS) award in 2012. Professor Niikura can be contacted at [email protected].

Discovering Rare Red Spiral Galaxy Population from Early Universe with the James Webb Space Telescope

The first image of NASA’s James Webb Space Telescope reveals a detailed morphology of highly redshifted spiral galaxies

Morphology of galaxies contain important information about the process of galaxy formation and evolution. With its state-of-the-art resolution, NASA’s James Webb Space Telescope has now captured several red spiral galaxies in its first image at an unprecedented resolution. Researchers from Waseda University have now analyzed these galaxies, revealing that these are among the furthest known spiral galaxies till date. The analysis further detected a passive red spiral galaxy in the early universe, a surprising discovery.

Spiral galaxies represent one of the most spectacular features in our universe. Among them, spiral galaxies in the distant universe contain significant information about their origin and evolution. However, we have had a limited understanding of these galaxies due to them being too distant to study in detail. “While these galaxies were already detected among the previous observations using NASA’s Hubble Space Telescope and Spitzer Space Telescope, their limited spatial resolution and/or sensitivity did not allow us to study their detailed shapes and properties,” explains Junior Researcher Yoshinobu Fudamoto from Waseda University in Japan, who has been researching galaxies’ evolution.

Now, NASA’s James Webb Space Telescope (JWST) has taken things to the next level. In its very first imaging of the galaxy cluster, SMACS J0723.3-7327, JWST has managed to capture infrared images of a population of red spiral galaxies at an unprecedented resolution, revealing their morphology in detail!

Against this backdrop, in a recent article published in The Astrophysical Journal Letters on 21 October 2022, a team of researchers comprising Junior Researcher Yoshinobu Fudamoto, Prof. Akio K. Inoue, and Dr. Yuma Sugahara from Waseda University, Japan, has revealed surprising insights into these red spiral galaxies. Among the several red spiral galaxies detected, the researchers focused on the two most extremely red galaxies, RS13 and RS14. Using spectral energy distribution (SED) analysis, the researchers measured the distribution of energy over wide wavelength range for these galaxies. The SED analysis revealed that these red spiral galaxies belong to the early universe from a period known as the “cosmic noon” (8-10 billion years ago), which followed the Big Bang and the “cosmic dawn.” Remarkably, these are among the farthest known spiral galaxies till date.

Rare, red spiral galaxies account for only 2% of the galaxies in the local universe. This discovery of red spiral galaxies in the early universe, from the JWST observation covering only an insignificant fraction of space, suggests that such spiral galaxies existed in large numbers in the early universe.

The researchers further discovered that one of the red spiral galaxies, RS14, is a “passive” (not forming stars) spiral galaxy, contrary to the intuitive expectation that galaxies in the early universe would be actively forming stars. This detection of a passive spiral galaxy in the JWST’s limited field of view is particularly surprising, since it suggests that such passive spiral galaxies could also exist in large numbers in the early universe.

Overall, the findings of this study significantly enhances our knowledge about red spiral galaxies, and the universe as a whole. “Our study showed for the first time that passive spiral galaxies could be abundant in the early universe. While this paper is a pilot study about spiral galaxies in the early universe, confirming and expanding upon this study would largely influence our understanding of the formation and evolution of galactic morphologies,” concludes Fudamoto.

Reference

Title of original paper: Red Spiral Galaxies at Cosmic Noon Unveiled in the First JWST Image
DOI: 10.3847/2041-8213/ac982b
Journal: The Astrophysical Journal Letters
Article Publication Date: October 21, 2022
Authors: Yoshinobu Fudamoto^1,2, Akio K. Inoue^1,3, and Yuma Sugahara^1,2
Affiliations:
¹Waseda Research Institute for Science and Engineering, Faculty of Science and Engineering, Waseda University
²National Astronomical Observatory of Japan
³Department of Physics, School of Advanced Science and Engineering, Faculty of Science and Engineering, Waseda University

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An international astronomer team has discovered the most distant galaxy candidate to date, named HD1, which is about 13.5 billion light-years away. This discovery implies that bright systems like HD1 existed as early as 300 million years after the Big Bang. This galaxy candidate is one of the targets of the James Webb Space Telescope launched late last year. If observations with the James Webb Space Telescope confirm its exact distance, HD1 will be the most distant galaxy ever recorded.

To understand how and when galaxies formed in the early Universe, astronomers look for distant galaxies. Because of the finite speed of light, it takes time for the light from distant objects to reach Earth. If an object is 1 billion light-years away, it means that the light left that object 1 billion years ago and had to travel for 1 billion years to reach us. Thus studying distant galaxies lets us look back in time.

The current record holder for the most distant galaxy is GN-z11, a galaxy 13.4 billion light-years away discovered by the Hubble Space Telescope. However, this distance is about the limit of Hubble’s detection capabilities.

HD1, a candidate object for the earliest/most-distant galaxy at 13.5 billion light-years away, was discovered from more than 1,200 hours of observation data taken by the Subaru Telescope, VISTA Telescope, UK Infrared Telescope, and Spitzer Space Telescope. “It was very hard work to find HD1 out of more than 700,000 objects,” says Yuichi Harikane, an assistant professor of ICRR, the University of Tokyo, who discovered HD1. “HD1’s red color matched the expected characteristics of a galaxy 13.5 billion light-years away surprisingly well, giving me a little bit of goosebumps when I found it.”

The team conducted follow-up observations using the Atacama Large Millimeter/submillimeter Array (ALMA) to confirm HD1’s distance. Akio Inoue, a professor at Waseda University, who led the ALMA observations, says, “We found a weak signal at the frequency where an oxygen emission line was expected. The significance of the signal is 99.99%. If this signal is real, this is evidence that HD1 exists 13.5 billion light-years away, but we cannot be sure without a significance of 99.9999% or more.”

HD1 is very bright, suggesting that bright objects already existed in the Universe only 300 million years after the Big Bang. HD1 is difficult to explain with current theoretical models of galaxy formation. Observational information on HD1 is limited and its physical properties remain a mystery. It is thought to be a very active star-forming galaxy, but it might be an active black hole. Either possibility makes it a very interesting object. In recognition of its astronomical importance, HD1 was selected as a target for the cycle 1 observations by the James Webb Space Telescope, launched last year. Yuichi Harikane, who is leading these observations, says, “If the spectroscopic observation confirms its exact distance, HD1 will be the most distant galaxy ever recorded, 100 million light-years further away than GN-z11. We are looking forward to seeing the Universe with the James Webb Space Telescope.”

This research will be published in the April 8, 2022 issue of The Astrophysical Journal as Yuichi Harikane, et al. “A Search for H-Dropout Lyman Break Galaxies at z~12-16”. This work was supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Society for the Promotion of Science (17H06130, 19J01222, 20K22358, 21K13953), and the NAOJ ALMA Scientific Research Grant (2020-16B).

Journal: The Astrophysical Journal
Title: “A Search for H-Dropout Lyman Break Galaxies at z~12-16”
Authors: Yuichi Harikane, Akio K. Inoue, Ken Mawatari, Takuya Hashimoto, Satoshi, Yamanaka, Yoshinobu Fudamoto, Hiroshi Matsuo, Yoichi Tamura, Pratika Dayal, L. Y. Aaron Yung, Anne Hutter, Fabio Pacucci, Yuma Sugahara, and Anton M. Koekemoer
DOI：10.3847/1538-4357/ac53a9
URL：https://iopscience.iop.org/article/10.3847/1538-4357/ac53a9
https://ui.adsabs.harvard.edu/abs/2021arXiv211209141H/abstract

New Study Suggests an Alternative Technique for Determining the True Activity of Catalysts

Researchers from Japan perform reliable estimation of the activity of water-splitting catalysts with an unconventional technique

Electrolysis of water into hydrogen and oxygen is a potential source of clean hydrogen fuel. However, the process requires efficient electrocatalysts. Unfortunately, conventional techniques often overestimate their efficiency. Now, researchers from Japan demonstrate an alternative technique for gauging the electrocatalytic performance accurately, opening doors to a smooth transition from lab-scale studies to large-scale hydrogen fuel generation and commercialization of new catalysts with no activity loss issues from overestimation of activity with transient voltammetry techniques.

Electrolysis of water or “water electrosplitting” has received a great deal of attention recently owing to its potential as a clean source of hydrogen, the oft-touted fuel of the future. However, two issues have long stood in the way: the large amount of energy lost, and the cost of electrocatalysts (catalysts used for electrolysis). Fortunately, several new kinds of electrocatalysts have made their appearance, which could potentially solve these issues.

The screening of new electrocatalysts is conventionally performed with techniques such as “linear sweep voltammetry” (LSV) and “cyclic voltammetry” (CV), which involve applying a constantly changing voltage to an electrode and monitoring the resulting current. As this current depends on the rate of oxidation or reduction occurring at the electrode, the measured current readings can be used to determine the effect of an electrocatalyst on the speed of the electrolysis reaction.

However, an obvious drawback of these techniques is that they cannot accurately record the “steady-state” response of the electrocatalyst as it does not experience a particular applied voltage long enough to do so. As a result, substantially high current readings are often recorded, which do not reflect the true catalytic activity, hindering the development of efficient electrocatalysts and promotion of the same to large-scale processes.

In a new study published in the Journal of The Electrochemical Society, Assistant Professor Sengeni Anantharaj from Waseda University, Japan, along with his collaborators Dr. Subrata Kundu from CSIR-Central Electrochemical Research Institute, India, and Prof. Suguru Noda from Waseda University have now found a way around this problem, demonstrating an alternate technique called “sampled current voltammetry” (SCV) as a more reliable indicator of electrocatalytic performance at a constant steady-state applied voltage.

“Screening catalysts accurately is just as important as developing new catalysts for all energy conversion reactions,” says Anantharaj, speaking of his motivation. “Our work has highlighted a way to make accurate measurements of electrocatalytic activity previously not possible with conventional transient techniques.”

Researchers from Waseda University, Japan, suggest an alternate technique for measuring steady-state electrocatalytic activity more reliably over conventional transient techniques, opening up a potential route to efficient hydrogen generation from water splitting.
Photo courtesy: Sengeni Anantharaj from Waseda University

Before applying the SCV technique, the researchers analyzed the errors resulting from LSV. To show the deviation in current values, they used a steady-state technique called “chronoamperometry” (CA), which is the most accurate method of all yet time consuming to measure current at constant voltages and compared it to the values obtained from LSV.

To determine the activity of electrocatalysts used in electrolysis, they measured the current readings of both the oxygen-producing and hydrogen-producing half-cell reactions. Using a stainless-steel (SS) electrode, precipitated Co(OH)₂ (cobalt hydroxide), and platinum foil as catalysts in a KOH (potassium hydroxide) solution, the researchers found that the current density readings from LSV and CA differed significantly, with the difference growing wider at higher applied voltages.

Using the same setup, they then applied the SCV technique and recorded the current densities at various fixed voltages obtained from the steady-state CA responses. “To validate the suitability of SCV, we recorded the CA responses of the SS electrode at various regularly increasing voltages for 130 seconds, within which the SS interface was able to reach a steady state,” elaborates Anantharaj.

From the sampled current readings, the researchers found negligible difference compared to the steady-state CA technique, demonstrating the reliability of the SCV in correctly determining electrocatalyst’s behavior at different voltages. Additionally, while the SCV is particularly useful in the search for a suitable electrocatalyst for water electrosplitting, it can be used to screen electrocatalysts accurately for any electrochemical reaction.

“By addressing the long-standing problem of catalyst performance loss when promoted from the lab to the practical processes, our work could speed up the worldwide adoption of large-scale hydrogen generation from electrolysis,” comments Anantharaj.

It certainly appears we’re now one step closer to the wide adaptation of hydrogen-powered future!

Reference

Authors: Sengeni Anantharaj^1,2, Subrata Kundu³ and Suguru Noda^1,2
Title of original paper: Worrisome Exaggeration of Activity of Electrocatalysts Destined for Steady-State Water Electrolysis by Polarization Curves from Transient Techniques
Journal: Journal of The Electrochemical Society
DOI: 10.1149/1945-7111/ac47ec
Latest Article Publication Date: 5 January 2022
Affiliations:
¹Department of Applied Chemistry, School of Advanced Science and Engineering, Waseda University
²Waseda Research Institute for Science and Engineering, Waseda University
³Electrochemical Process Engineering (ECE) Division, CSIR-Central Electrochemical Research Institute (CECRI), India

Unveiling Galaxies at Cosmic Dawn That Were Hiding Behind the Dust

Scientists serendipitously discover two heavily dust-enshrouded galaxies that formed when the Universe was only 5% of its present age

While investigating the data of young, distant galaxies observed with the Atacama Large Millimeter/submillimeter Array, Dr. Yoshinobu Fudamoto from Waseda University and the National Astronomical Observatory of Japan noticed unexpected emissions coming from seemingly empty regions in space that, a global research team confirmed, came actually from two hitherto undiscovered galaxies heavily obscured by cosmic dust. This discovery suggests that numerous such galaxies might still be hidden in the early Universe, many more than researchers were expecting.

A schematic of the results of this research. ALMA revealed a hitherto undiscovered galaxy as it is buried deep in dust (artist’s impression in upper right) in a region where the Hubble Space Telescope could not see anything (left). Researchers serendipitously discovered the new hidden galaxy while observing an already well-known typical young galaxy (artist’s impression in lower right)
Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope

When astronomers peer deep into the night sky, they observe what the Universe looked like a long time ago. Because the speed of light is finite, studying the most distant observable galaxies allows us to glimpse billions of years into the past when the Universe was very young and galaxies had just started to form stars. Studying this “early Universe” is one of the last frontiers in astronomy and is essential for constructing accurate and consistent astrophysics models. A key goal of scientists is to identify all the galaxies in the first billion years of cosmic history and to measure the rate at which galaxies were growing by forming new stars.

Various efforts have been made over the past decades to observe distant galaxies, which are characterized by electromagnetic emissions that become strongly redshifted (shifted towards longer wavelengths) before reaching the Earth. So far, our knowledge of early galaxies has mostly relied on observations with the Hubble Space Telescope (HST) and large ground-based telescopes, which probe their ultra-violet (UV) emission. However, recently, astronomers have started to use the unique capability of the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to study distant galaxies at submillimeter wavelengths. This could be particularly useful for studying dusty galaxies missed in the HST surveys due to the dust absorbing UV emission. Since ALMA observes in submillimeter wavelengths, it can detect these galaxies by observing the dust emissions instead.

In an ongoing large program called REBELS (Reionization-Era Bright Emission Line Survey), astronomers are using ALMA to observe the emissions of 40 target galaxies at cosmic dawn. Using this dataset, they have recently discovered that the regions around some of these galaxies contain more than meets the eye.

While analyzing the observed data for two REBELS galaxies, Dr. Yoshinobu Fudamoto of the Research Institute for Science and Engineering at Waseda University, Japan, and the National Astronomical Observatory of Japan (NAOJ), noticed strong emission by dust and singly ionized carbon in positions substantially offset from the initial targets. To his surprise, even highly sensitive equipment like the HST couldn’t detect any UV emission from these locations. To understand these mysterious signals, Fudamoto and his colleagues investigated matters further.

In their latest paper published in Nature, they presented a thorough analysis, revealing that these unexpected emissions came from two previously unknown galaxies located near the two original REBELS targets. These galaxies are not visible in the UV or visible wavelengths as they are almost completely obscured by cosmic dust.  One of them represents the most distant dust-obscured galaxy discovered so far.

Distant galaxies imaged with ALMA, the Hubble Space Telescope, and the European Southern Observatory’s VISTA telescope. Green and orange colors represent radiations from ionized carbon atoms and dust particles, respectively, observed with ALMA, and blue represents near-infrared radiation observed with VISTA and Hubble Space Telescopes.
REBELS-12 and REBELS-29 detected both near-infrared radiation and radiation from ionized carbon atoms and dust. On the other hand, REBELS-12-2 and REBELS-29-2 have not been detected in the near-infrared, which suggests that these galaxies are deeply buried in dust.
Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, ESO, Fudamoto et al.

What is most surprising about this serendipitous finding is that the newly discovered galaxies, which formed more than 13 billion years ago, are not strange at all when compared with typical galaxies at the same epoch. “These new galaxies were missed not because they are extremely rare, but only because they are completely dust-obscured,” explains Fudamoto. However, it is uncommon to find such “dusty” galaxies in the early period of the Universe (less than 1 billion years after the Big Bang), suggesting that the current census of early galaxy formation is most likely incomplete, and would call for deeper, blind surveys. “It is possible that we have been missing up to one out of every five galaxies in the early Universe so far,” Fudamoto adds.

The researchers expect that the unprecedented capability of the James Webb Space Telescope (JWST) and its strong synergy with ALMA would lead to significant advances in this field in the coming years. “Completing our census of early galaxies with the currently missing dust-obscured galaxies, like the ones we found this time, will be one of the main objectives of JWST and ALMA surveys in the near future,” states Pascal Oesch from University of Geneva.

Overall, this study constitutes an important step in uncovering when the very first galaxies started to form in the early Universe, which in turn shall help us understand where we are standing today.

Reference

Authors: Y. Fudamoto^1,2,3, P. A. Oesch^1,4, S. Schouws⁵, M. Stefanon⁵, R. Smit⁶, R. J. Bouwens⁵, R. A. A. Bowler⁷, R. Endsley⁸, V. Gonzalez^9,10, H. Inami¹¹, I. Labbe¹², D. Stark⁸, M. Aravena¹³, L. Barrufet¹, E. da Cunha^14,15, P. Dayal¹⁶, A. Ferrara¹⁷, L. Graziani^{18,20, 27}, J. Hodge⁵, A. Hutter¹⁶, Y. Li^21,22, I. De Looze^23,24, T. Nanayakkara¹², A. Pallottini¹⁷, D. Riechers²⁵, R. Schneider^18,19,26,27, G. Ucci1⁶, P. van der Werf⁵, C. White⁸
Title of original paper: Normal, Dust-Obscured Galaxies in the Epoch of Reionization
Journal: Nature
DOI: 10.1038/s41586-021-03846-z
Affiliations:
¹Department of Astronomy, University of Geneva
²Research Institute for Science and Engineering, Waseda University; ³National Astronomical Observatory of Japan
⁴Cosmic Dawn Center (DAWN), Niels Bohr Institute, University of Copenhagen
⁵Leiden Observatory, Leiden University
⁶Astrophysics Research Institute, Liverpool John Moores University
⁷Sub-department of Astrophysics, The Denys Wilkinson Building, University of Oxford
⁸Steward Observatory, University of Arizona
⁹Departmento de Astronomia, Universidad de Chile
¹⁰Centro de Astrofisica y Tecnologias Afines (CATA)
¹¹Hiroshima Astrophysical Science Center, Hiroshima University
¹²Centre for Astrophysics & Supercomputing, Swinburne University of Technology
¹³Nucleo de Astronomia, Facultad de Ingenieria y Ciencias, Universidad Diego Portales
¹⁴International Centre for Radio Astronomy Research, University of Western Australia
¹⁵ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)
¹⁶Kapteyn Astronomical Institute, University of Groningen
¹⁷Scuola Normale Superiore
¹⁸Dipartimento di Fisica, Sapienza, Universita di Roma
¹⁹INAF/Osservatorio Astronomico di Roma
²⁰INAF/Osservatorio Astrofisico di Arcetri
²¹Department of Astronomy & Astrophysics, The Pennsylvania State University
²²Institute for Gravitation and the Cosmos, The Pennsylvania State University
²³Sterrenkundig Observatorium, Ghent University
²⁴Dept. of Physics & Astronomy, University College London
²⁵Cornell University
²⁶Sapienza School for Advanced Studies
²⁷INFN, Roma, Italy