Researchers review the latest results and understanding of mechanisms behind this new field of research where seeds show higher yields and resilience following flash treatment in low-temperature plasma. 

Every once in a while, the sun unleashes powerful flares and coronal mass ejections which hurl plasma and energetic particles into space. On the infant Earth, this solar activity drove cascades of atmospheric chemical reactions that may have helped form the building blocks of life. More recently, scientists have discovered that applying plasma to seeds in a controlled way can trigger similar activity to make them more fast-growing and resilient. Researchers at ºÚÁϳԹÏÍø and Kyushu University in Japan have compiled a comprehensive review of this new field ¡ª termed ¡°Plasma Agriculture¡± ¡ª a potential sustainable solution to address global food shortage.

The word plasma brings to mind a hot, ionized inferno that makes up the fourth state of matter. But the plasma used here is different. By applying high electric voltage to air or any gas, electrons from a tiny fraction of its molecules get stripped off and gain very high energies. These electrons zipping around can effectively mimic the behavior of plasma even though the bulk of the gas remains at room temperature.

This low-temperature plasma, in turn, can be applied directly to seeds without burning them. Excessive use of chemicals and genetic modification of plants are a cause of concern for many people. In its place, plasma agriculture can offer similarly high crop yields without intrusion. 

¡°Low temperature plasma is an alternative to genetically modified crops¡±, said Kenji Ishikawa, professor at ºÚÁϳԹÏÍø¡¯s . 

In a review published in the , Ishikawa and his collaborators at Kyushu University synthesize data from over 30 crop species and find that in more than two?thirds of reported studies, well?tuned plasma treatments boost seed vigor or yield, while the remaining cases show neutral or even negative effects when the dose is not properly controlled.

However, to ship this technology from the lab to the farm, a deeper understanding of the physical and biochemical processes through which low temperature plasma acts is necessary. For that reason, this review also summarizes the present state of knowledge of how and why plasma treatment works.

Plasma power for stronger seeds

Low-temperature plasma mainly operates by letting its energetic electrons collide with air molecules. This excites oxygen and nitrogen in air and breaks their bonds, generating Reactive Oxygen and Nitrogen Species (RONS) such as hydroxyl radicals, nitrates, nitrites, peroxides, and superoxides. RONS are wildly temperamental ¡ª they set off several cascades of chemical activity in living systems. Too many of them, and they can damage cells and tissues. But in just the right amounts, RONS act as signaling molecules in cells that lead to faster germination and enhanced seed growth.

That is why pinpointing the beneficial chemistry of plasma-induced RONS is crucial in determining for how long and at what intensity these plasma treatments should be applied. 

The pathways currently being researched include seed coat and surface changes, inactivation of surface pathogens, phytohormone-induced growth enhancement, and increased water and nutrient uptake. The reviewers find that many of these processes are interconnected and act together to drive plasma¡¯s agricultural value.

The pathway that excites Ishikawa the most is epigenetic modification. If you think of the DNA as an operating system with encoded programs, epigenetics determines which programs are run and which ones are not, Ishikawa notes. This is different from genetic modification which introduces changes in the programs itself, potentially harboring risks. Studies show plasma-induced epigenetic changes cause positive expression of plant genes involved in germination, stress tolerance, and metabolism.

An eco-friendly fertilizer

Another way low?temperature plasma can help farmers is by treating water and soil rather than just seeds. Air is rich in nitrogen which is also a vital element for plant growth. But the notoriously hard-to-break triple bond in a nitrogen molecule makes it difficult for plants to use it directly. Therefore, nitrogen must first be ¡°fixed¡± by microbes, lightning, or artificially in energy-hungry and high-emission Haber-Bosch reactors. Low-temperature plasma offers an alternative: its electrical discharges can convert nitrogen in or into ammonia, nitrites, and nitrates in plasma-activated water that can be used as a fertilizer powered by electricity in place of fossil fuels. 

In recent times, global food production has been under tremendous stress due to changing weather patterns and a growing need to feed disparate populations. ºÚÁϳԹÏÍø¡¯s Center for Low-temperature Plasma Sciences unites physicists, biochemists, and agriculturists to help find sustainable solutions to this problem.

Publication information: 

Pankaj Attri, Kenji Ishikawa, Kazunori Koga, 2026. Sunlight to Plasma: Mimicking nature¡¯s light for smarter agriculture and crop production, Journal of Advanced Research. DOI:

Funding information:

This work is supported by JSPS-KAKENHI grant number , , and . Additionally, partly funded by JSPS KAKENHI Grant Number , , JSPS Core-to-Core Program ¡°Data Driven Plasma Science¡±, Plasma Bio Consortium, and Center for Low-temperature Plasma Sciences, ºÚÁϳԹÏÍø.

Expert contact: 

Kenji Ishikawa
Center for Low-temperature Plasma Studies, ºÚÁϳԹÏÍø
Email: ishikawa.kenji.s1@f.mail.nagoya-u.ac.jp

Media contact: 

Sumeet Kulkarni 
International Communications Office 
ºÚÁϳԹÏÍø 
Email: icomm_research@t.mail.nagoya-u.ac.jp 

Top Image:

A sample of Yardlong Bean Seeds (Vigna unguiculata var. sesquipedalis) being treated under low-temperature plasma. Credit: Sumeet Kulkarni, ºÚÁϳԹÏÍø

Scientists use clues from inhabitants and ocean current simulations to show how a small piece of plastic waste can transport a micro-ecosystem to new regions

Researchers have traced the journey of a plastic bottle cap recovered near the waters of southern Japan by combining data from the label, chemical clues in tiny shells, and ocean current simulations. They found 307 organisms, including a polychaetae worm not found in Japanese waters before. The findings, published in , show that when species that significantly shape their environments (ecosystem engineers) colonize plastic debris, entire micro-communities can be transported over extended periods, with implications for invasive species risk and marine biodiversity conservation. 

Marine plastic waste poses direct threats such as ingestion and entanglement but can also transport attached organisms to distant locations. Plastic can remain at the sea surface longer than natural drifting materials such as wood or seaweed. Consequently, marine plastics represent a growing pathway for dispersing organisms to new regions. 

This is the first study to combine information from the organisms attached, chemical records of past environmental conditions preserved in shells, and ocean current simulations to trace a single small piece of ocean plastic. ? 

Bottle cap habitat engineered by a worm 

Nine taxonomic groups and 307 individuals were found, including tiny tube-building worms, bryozoans (tiny colonial filter-feeders), gooseneck barnacles, foraminifera, flatworms, and larger polychaete worm species. ºÚÁϳԹÏÍø three-quarters of the individuals were tiny worms that build coiled calcareous tubes.  

“The most striking colonist was a polychaete worm, Eunice bipapillata, which had built a nest that transformed the cap into a complex three-dimensional habitat. Inside, we found organisms that normally live in southern tropical waters,” said Naoto Jimi, lead author and lecturer at ºÚÁϳԹÏÍø’s . “Geographic range extensions of some species may be occurring under the radar, so if this waste can be properly disposed, we may reduce the number of non-native species carried into new habitats.”

Evidence to trace the origins and drift route 

The researchers investigated where the cap originated, the water temperatures it had passed through, and whether those temperatures matched the sea surface temperatures along drift paths predicted by ocean current simulations. Three sources of evidence were used: 

1. Biofouling community: The coexistence of coastal seafloor and reef species as well as typical open-ocean foulers (organisms that attach to floating objects in the ocean) suggested that the cap had passed through both coastal and open-ocean environments. 

2. Foraminiferal stable isotopes: Foraminifera, single-celled organisms that build intricate shells, record ambient water temperature as they grow their shells. Stable isotope analysis measures the ratios of isotopes of an element to obtain clues about the environment an organism has experienced. Analysis of different parts of the shells suggested that the specimens had experienced warmer waters before reaching the collection site, where the water temperature was about 22 degrees Celsius. 

3. Ocean current modeling: Using surface drift current simulations, virtual particles were released into ocean current models to reproduce possible drift paths of debris. They indicated that the cap likely drifted from the northern Philippines on the Kuroshio system and reached the collection area in at least 70 days and up to several months.

Small plastics, big consequences

This study shows that when ecosystem engineers such as tube-building worms colonize small plastic fragments, these plastics may serve as shelters and transport vehicles that allow multiple organisms to survive together. This may result in entire biological communities reaching new regions.  

¡°The marine plastic problem should therefore be considered not only from the perspectives of aesthetic damage, ingestion, and entanglement, but also from those of biogeography and invasive species risk,¡± said Jimi. ¡°Multi-method reconstructions of the drift history of marine debris may support future estimation and control of invasive species pathways originating from ocean waste.¡± 

The researchers conclude that future research should quantify how frequently small plastics host organisms found at the bottom of marine habitats, identify which taxa are most likely to survive during drift, and evaluate ecological outcomes if debris-borne organisms arrive and establish in new environments. 

Publication information: 

Naoto Jimi, Naoki Saito, Akito Ogawa, Hiroki Kise, Natsumi Hookabe, Toyoho Ishimura, Masashi Tsuchiya, 2026. Multi-proxy reconstruction of bottle-cap rafting using biofouling communities, stable isotopes and drift modeling, Marine Pollution Bulletin, 232,120051. DOI:

Funding information:

This research was supported by the Narishige Zoological Science Award and JSPS KAKENHI (22K15165). 

Expert contact: 

Naoto Jimi  
Sugashima Marine Biological Laboratory 
ºÚÁϳԹÏÍø 
Email: jimi.naoto.p0@f.mail.nagoya-u.ac.jp 

Media contact: 

Merle Naidoo
International Communications Office
ºÚÁϳԹÏÍø
Email: icomm_research@t.mail.nagoya-u.ac.jp 

Top image:

Inside a 3.5 cm plastic bottle cap: A miniature ecosystem of 307 organisms drifted from the Philippines to waters south of Japan. Credit: Sugashima Marine Biological Laboratory, ºÚÁϳԹÏÍø

Gallium-doped zinc oxide nanosheets enable a single pixel to detect red, green and blue light.

Researchers at ºÚÁϳԹÏÍø in Japan have developed gallium-doped zinc oxide (GZO) nanosheets that may enhance camera resolution in compact devices, including smartphones and medical endoscopes.

These nanosheets enable a single pixel to detect the intensity of red, green, and blue (RGB) light while remaining nearly transparent, unlike conventional sensors. They are ultrathin, lightweight, and can withstand temperatures up to 400 degrees Celsius, making them suitable for extreme environments such as space hardware and automotive systems. The findings were published in the journal .

Why a single pixel matters

Most commercial cameras use a Bayer array, arranging RGB color filters in a checkerboard pattern across millions of pixels. Since each pixel senses only one color, full-color images are reconstructed from neighboring pixels. If a single pixel could detect all three colors, the total pixel count could be cut by up to 75%, thereby shrinking the sensor while maintaining image resolution.

Transparent nanosheets are ideal for this approach because they allow light to pass through, enabling multiple layers to be stacked vertically, with each layer detecting a different color. Nanosheet sensors also eliminate the complex semiconductor processes required by conventional RGB sensors, simplifying production and reducing costs.

Improving the nanosheets’ weak point

A research team led by Professor , along with researchers Ruben Canton-Vitoria, and Vivid Meelab at ºÚÁϳԹÏÍø’s focused on zinc oxide nanosheets, which are highly transparent and chemically stable. However, their initial experiments revealed that these nanosheets responded weakly to visible light, limiting their suitability for camera sensors.

To address this limitation, the team customized the electronic structure of zinc oxide by adding gallium, creating trap states that capture electrons and convert light into electrical signals. This modification enabled the nanosheets to respond strongly to visible light while maintaining their transparency.

Outperforming commercial sensors

Analysis showed that gallium-doped zinc oxide nanosheets convert only 0.005% of absorbed light energy into photocurrent, while each layer transmits 99.995% of visible light.

Despite minimal energy use, the modified nanosheets achieved a sensitivity of 800 amperes per watt (A/W), far exceeding the typical 10 A/W of commercial sensors. The trap states enable a strong response to small amounts of absorbed light, while most light passes through to subsequent layers.

This property enables color-selective stacking. The team developed an ultrathin sensor where the first GZO layer uses photoactive trap states to detect the full visible spectrum. After filtering out red light, a second GZO layer detects the green and blue components. A final green-cut filter isolates the last layer for blue detection. Experiments confirmed that the device successfully reproduces full-color images with half the error of conventional cameras.

“This optical sensor closely resembles how the human retina discriminates RGB colors,” said lead author Osada. “The brain reconstructs color by combining the responses of three types of visual cells, each sensitive to different wavelengths.”

Future perspectives

In addition to strong optical performance, the device maintained a stable light response up to 400 degrees Celsius in air and consistent performance in both vacuum and humid conditions. These thermal and chemical properties make it suitable for demanding environments, including space hardware and automotive systems.

The sensor can also be manufactured using a room-temperature solution process, eliminating the need for high-temperature processing and complex microfabrication required by conventional sensors.

By integrating multiple light-detection functions into a single device, the team has demonstrated a path toward smaller, more integrated, and higher-performing optoelectronic devices at lower cost than current cameras.

Paper information:

Vivid Meelab, Ruben Canton-Vitoria, Mohammad Furqan, Yoshinori Morita, Shu Morita, Eisuke Yamamoto, Makoto Kobayashi, Raul Arenal, and Minoru Osada (2026). Highly Transparent Gallium-Doped Zinc Oxide Nanosheets Enabling Stable All-in-One Red-Green-Blue Photodetectors with High Responsivity, ACS Nano, .

Expert contact:

Ruben Canton-Vitoria
Institute of Materials and Systems for Sustainability, ºÚÁϳԹÏÍø
Email: rcanton@imass.nagoya-u.ac.jp

Minoru Osada
Institute of Materials and Systems for Sustainability, ºÚÁϳԹÏÍø
Email: mosada@imass.nagoya-u.ac.jp

Media contact:

Naomi Inoue
International Communications Office, ºÚÁϳԹÏÍø
Email: icomm_research@t.mail.nagoya-u.ac.jp

Top image:

Gallium-doped ZnO (GZO) nanosheets combine >97% optical transparency with strong visible-light photoresponse, enabling an all-in-one RGB photodetector that simultaneously resolves red, green, and blue signals within a single pixel. The stacked devices retain stable operation up to 400 ¡ãC, making them promising for next-generation image sensors used in space, automotive, and high-radiation environments.
(Credit: Minoru Osada & Ruben Canton-Vitoria)

The workshop opened with remarks from Professor Hiroki Tanikawa, Dean of GSES, who drew a natural parallel between the school’s interdisciplinary approach, which integrates environmental, social, and cultural dimensions, and the very nature of watershed management, pointing to the Kiso River Basin as an example. He emphasized the importance of collaboration of various local governments in watershed areas, the role of coordinated governance, shared vision, and inter-municipal cooperation in achieving effective watershed management.

This was followed by the presentation of Dr. Charles John Gunay of University of the Philippines Los Ba?os, School of Environmental Science and Management (UPLB SESAM), on the use of modeling tools for flood and sediment risk assessment. Using case studies such as the Santa Rosa¨CSilang Watershed and the Ogouchi Dam Watershed, he demonstrated how simulations can identify erosion, sediment transport, and high-risk areas. He also shared insights from a -funded project and emphasized the importance of translating technical results into actionable information for decision-makers and communities through participatory approaches.

Ms. Lemuelle Celis of Department of Environment and Natural Resources (DENR) presented the current state of watershed management in the Philippines, highlighting challenges such as overlapping institutional mandates, watershed degradation, and increasing climate vulnerability. She also outlined ongoing initiatives, including improved monitoring systems, integrated management planning, and conservation efforts, while noting the need for greater capacity-building and financial support.

Dr. Taichi Minamitani of JICA discussed the JICA¡¯s approach to flood control in the Philippines, emphasizing the need for proactive investments in disaster risk reduction amid rising economic losses. He outlined strategies to strengthen governance and infrastructure, highlighting long-term efforts in Metro Manila such as river widening and flood diversion. He also noted key challenges in flood control, including limited upstream storage, insufficient river capacity, and urban pressures, underscoring the importance of integrated and forward-looking flood protection planning.

The panel discussion, moderated by Professor Kiichiro Hayashi of Graduate School of Engineering, explored the vital roles of academia, government, non-government and international institutions in addressing the challenges on watershed management. Ms. Celis and Mr. Yamada emphasized the critical role of coordination with local government units and various sectors, as well as the importance of effective data-sharing mechanisms in achieving integrated watershed management. Mr. Yamada also noted that in developing countries, where local capacities may be limited, international cooperation can play a vital role in strengthening watershed management efforts.

Dr. Gunay emphasized the need for improved instrumentation and monitoring in watershed management as a key area for future research. He highlighted the role of academia in providing technical capacity, scientific data, and mentoring, and noted that collaboration between institutions such as University of the Philippines Los Ba?os and ºÚÁϳԹÏÍø can help bridge gaps between technical and non-technical stakeholders, particularly in strengthening government capacity.

Dr. Minamitani emphasized that JICA expects him to promote sustainable river basin management by fostering an understanding of the importance of flood control measures and encouraging relevant organizations to change their behavior. He also called on the academic community to focus not on developing a variety of models, but on producing outputs that contribute to changing the behavior of relevant organizations, so that they can tackle flood control from a scientific perspective with a view to supporting development in each country. He also highlighted the importance of strengthening Japan-Philippines collaboration, improving stakeholder coordination, and building on the Philippines¡¯ strengths in disaster risk reduction and watershed management.

Mr. Toru Uemachi, Director General of JICA Chubu concluded the workshop by expressing appreciation to all participants and highlighting the event as a starting point for broader collaboration, including cross-learning on watershed management between Japan and the Philippines. He reaffirmed JICA¡¯s commitment to supporting joint initiatives and encouraged continued dialogue and partnership between stakeholders from both countries.

Held on March 16-17, 2026, the two-day workshop highlighted the growing importance of bamboo as a versatile and renewable resource with wide-ranging applications in energy, construction, and environmental management. It also served as a valuable platform for knowledge exchange, enabling participants to identify shared challenges and explore opportunities for joint research and innovation between Japan and the Philippines.

Technology, innovation, and opportunities in bamboo research

Session 1 took place on March 16 at the Environmental Studies Hall on the Higashiyama Campus. Researchers from both countries exchanged insights and experiences, followed by a panel discussion on potential areas for collaboration.

Professor Hiroki Tanikawa, Dean of the Graduate School of Environmental Studies, opened the session by stressing the importance of greater collaborative research on bamboo as a strategic resource for sustainable development.

Associate Professor Masahiro Nagao of ºÚÁϳԹÏÍø led off the presentation, introducing innovative work on utilizing bamboo as a source of hydrogen and methanol through electrolysis, as well as the application of LiDAR technologies for bamboo forest monitoring in Japan.

Representing the Philippine perspective on bamboo as a renewable energy source, Dr. Anniver Ryan Lapuz of the Forest Products Research and Development Institute (FPRDI), Department of Science and Technology (DOST), Philippines, then presented research on bamboo pellet production and densification technologies as possible source of bioenergy. The presentation detailed the process of converting bamboo into pellets, including collection, drying, and processing methods, with energy density calculations showing comparable results to rice straw.

Associate Professor Hiroaki Shirakawa of ºÚÁϳԹÏÍø discussed the social and economic value of bamboo, including the potential for carbon credits through bamboo biochar production. He concluded that while carbon credits alone cannot cover management costs, a comprehensive evaluation of bamboo utilization must consider both economic and social benefits, such as the need for better database management and life cycle assessment of bamboo products.

Ms. Aralyn Quintos of DOST-FPRDI presented their research on bamboo durability and thermal modification techniques, finding that thermally modified bamboo with polyurethane coatings showed superior durability compared to untreated bamboo. She also discussed the evolving bamboo industry in the Philippines, from traditional uses to modern applications in construction, furniture, and engineered bamboo products. The presentation concluded with an overview of the DOST-FPRDI¡¯s R&D Roadmap for 2025-2032, focusing on transitioning from basic property evaluation to advanced industrial applications and establishing a circular bioeconomy.

The presentations were followed by a panel discussion moderated by Dr. Marianne Faith G. Martinico-Perez of the Asian Satellite Campuses Institute (ASCI) and GSES. The discussion underscored the challenges in bamboo sourcing and processing technologies, as well as the complementary strengths of Japan and the Philippines: Japan¡¯s expertise in advanced technologies and material science, and the Philippines¡¯ strong foundation in bamboo resources and applied research.

Several priority areas for collaboration were identified, including leveraging the advanced laboratory facilities and analytical techniques available at ºÚÁϳԹÏÍø for the characterization of Philippine bamboo species; the joint development of low-cost, environmentally friendly adhesives for engineered bamboo; the design and transfer of affordable processing technologies and machinery; and collaborative research on life cycle assessment (LCA) and socio-economic impacts.

In his closing remarks, Professor Akira Yamauchi, Director of the Asian Collaborative Development Department of ºÚÁϳԹÏÍø, emphasized the importance of sustained collaboration and expressed optimism about strengthening partnerships with Philippine institutions.

Field-based learning and technology demonstration

Session 2 was held on March 17 at the Higashiyama Zoo and Botanical Gardens for hands-on, field-based learning activities. The session showcased various bamboo species found in Japan and offered demonstrations on the application of advanced tools and methodologies, such as the use of LiDAR technologies for bamboo forest monitoring and non-destructive techniques for bamboo species characterization.

The workshop reaffirmed a shared commitment between ºÚÁϳԹÏÍø and its Philippine partners to advance bamboo as a key resource for sustainable development, climate action, and inclusive economic growth through joint research, technology development, and capacity-building initiatives.

This forum brings together experts from the International Center for Research and Education in Agriculture (ICREA) and the Center for Low-Temperature Plasma Sciences (cLPS), ºÚÁϳԹÏÍø, as well as the LPGP, University of Paris-Saclay, to discuss groundbreaking research and applications in plasma agriculture.

Date

March 10, 2026 15:00-18:00

Venue

Ohkuma Hall, Ohkuma Building, ºÚÁϳԹÏÍø (C2-7)

As part of their continuing collaboration, the Graduate School of Environmental Studies (GSES) and the Asia Collaborative Development Department will hold the Nagoya¨CPhilippines Workshop on Bamboo Research and Sustainability on March 16-17, 2026.

This two-day workshop aims to provide a platform for the exchange of knowledge, research findings in bamboo-based science and technology between Japan and the Philippines, and identify priority areas for Nagoya¨CPhilippines collaborative research initiatives in bamboo and sustainability.

The workshop will be conducted in two (2) sessions, as outlined below:

Session 1 ¨C Open Session

Date & Time: March 16, 2026 (14:00¨C16:00 JST)
Venue: ºÚÁϳԹÏÍø, Environmental Studies Building, 1F Lecture Hall
Participation: Open to all participants (on-site and online) – Registration is encouraged

Zoom Access: Nagoya¨CPhilippines Bamboo Workshop

Meeting ID: 883 6296 0074
Passcode: GSES

Session 2 ¨C By Invitation Only

Date & Time: March 17, 2026 (9:00¨C12:00 JST)
Venue: Higashiyama Zoo and Botanical Garden

ºÚÁϳԹÏÍø researchers break conventional rules to develop heat-resistant, recyclable metal alloys for automotive and aerospace use.

Aluminum is prized for being lightweight and strong, but at high temperatures it loses strength. This has limited its use in engines, turbines, and other applications where parts must stay strong under high temperature conditions. Researchers at ºÚÁϳԹÏÍø have developed a method that uses metal 3D printing to create a new aluminum alloy series optimized for high strength and heat resistance. All new alloys use low-cost, abundant elements, and are recycling-friendly, with one variant staying both strong and flexible at 300¡ãC. The study was published in . 

Breaking with tradition to create the perfect aluminum alloy

¡°The design centers on iron, which metallurgists usually don¡¯t add to aluminum because it makes the metal brittle and vulnerable to corrosion,¡± Naoki Takata, lead author and professor at ºÚÁϳԹÏÍø , explained.

¡°The extreme cooling rates in laser powder bed fusion, which is a representative process of metal 3D printing technologies, cause molten metal to solidify in seconds. This changes fundamental rules¡ªthe rapid cooling traps iron and other elements in arrangements (formation of metastable phases) that can¡¯t form under normal manufacturing conditions. By carefully selecting which elements to add, we created new alloys that are both heat-resistant and strong.¡±

The researchers developed a systematic method to predict which elements will strengthen the aluminum matrix and which will form protective micro or nano structures. They tested these predictions by creating new alloys with copper, manganese, and titanium, and then confirmed the results through electron microscopy.

The best performing alloy contains aluminum, iron, manganese, and titanium (Al-Fe-Mn-Ti), and outperforms all other 3D-printed aluminum materials by combining strength at high temperatures with flexibility at room temperature.

¡°Our method relies on established scientific principles about how elements behave during rapid solidification in 3D printing and is applicable to other metals. The alloys also proved easier to 3D print than conventional high-strength aluminum, which frequently cracks or warps during fabrication,¡± Professor Takata noted.

Watch how advanced aluminum alloys are made using 3D printing. ?This video shows a laser melting metal powder layer by layer to create strong, lightweight aluminum parts. Copper, manganese, and titanium are added to improve strength, durability, and performance. Credit: Aichi Center for Industry and Science and Technology, Toyota

Lighter vehicles, fewer emissions 

The new materials could enable lightweight aluminum components in parts that operate at elevated temperatures, such as compressor rotors and turbine components. Lighter vehicles consume less fuel and produce fewer emissions. 
 
The aerospace industry may also benefit, as aircraft engines require materials that combine light weight with heat resistance. Beyond these applications, the research provides a framework for designing new classes of metals specifically for 3D printing, with potential to accelerate development across multiple industries.

Paper information: 

Naoki Takata, Koki Minamihama, Takanobu Miyawaki, Yue Cheng, Yifan Xu, Wenyuan Wang, Dasom Kim, Asuka Suzuki, Makoto Kobashi, and Masaki Kato (2025). Design of high-performance sustainable aluminum alloy series for laser additive manufacturing. Nature Communications, 16, 11105. DOI:

Funding information: 

This research was supported by JST PRESTO (Grant JP22688912) and JSPS KAKENHI (Grant 24H00378).

Research Contact: 

Naoki Takata 
Graduate School of Engineering 
ºÚÁϳԹÏÍø 
Email: takata.naoki@material.nagoya-u.ac.jp

Media Contact: 

Merle Naidoo
International Communications Office
ºÚÁϳԹÏÍø
Email: icomm_research@t.mail.nagoya-u.ac.jp

Top image:

Microscope image showing the layered structure of a new 3D-printed aluminum alloy. The wave-like patterns are ¡°melt pools,¡± traces left by the laser as it melted metal powder layer by layer. The small dark dots are nanoscale particles that give the alloy its exceptional strength and heat resistance. Credit: Takata et al., 2025 

Research shows how markets respond when firms back environmental and social commitments with rigorous disclosure

Companies with strong environmental, social, and governance (ESG) track records performed better than their peers after being required to adopt more rigorous auditing standards. This is according to a new study from researchers at ºÚÁϳԹÏÍø, which is the first to examine the connection between the implementation of ¡°key audit matters¡± (KAMs) and firms¡¯ sustainability practices.

ESG stands for environmental, social, and governance¡ªa framework for evaluating how companies manage environmental impacts, treat stakeholders, and maintain ethical oversight. Companies with strong ESG practices demonstrate long-term commitment to sustainability and social responsibility. Investors increasingly view these commitments as an important signal of corporate quality.

In 2015, the International Auditing and Assurance Standards Board (IAASB) recommended that auditors communicate KAMs, the most significant issues identified during an audit, to better inform investors about company risks. Although Japanese firms with high ESG scores tended to pay higher fees for auditing and related consulting services after the implementation of KAMs, they also performed better in both accounting and market indicators.

¡°You can¡¯t simply buy credibility by paying for expensive audits,¡± clarified co-author Hu Dan Semba, Associate Professor at ºÚÁϳԹÏÍø¡¯s Graduate School of Economics. ¡°But if you¡¯ve demonstrated commitment to sustainability practices, then investing in more transparent auditing amplifies that credibility, and markets reward it.¡±

As more countries adopt similar standards, the research offers insights into which companies are likely to benefit the most from transparency requirements. The results were published in Managerial Auditing Journal.

A transparency experiment in Japan

The case of Japan provides a unique scenario for studying the implementation of stricter auditing standards. Publicly traded companies were given the option to voluntarily adopt KAMs early in fiscal year 2019, before the practice was made mandatory in fiscal year 2020. This created a natural experiment for exploring the motivations behind corporate behavior.

The research team, led by Semba and co-author Maretno Agus Horjoto of Pepperdine University, analyzed 1,065 Japanese firms from 2009 through 2023, tracking which companies adopted transparency requirements early, what it cost them, and how they performed afterward.

Twenty-four non-financial firms volunteered for early adoption, and the analysis showed that the decision to volunteer was positively related to a firm¡¯s ESG score. ¡°These companies stepped forward when they didn¡¯t have to,¡± Semba noted, ¡°demonstrating their interest in signaling their underlying quality.¡± However, sustainability-focused companies also tended to pay more for auditing and non-auditing services compared to their peers. These costs reflect more rigorous examinations and additional advisory work to address issues identified during audits.

The researchers, citing scholarship on Japanese business culture, suggest that this willingness to voluntarily embrace transparency may reflect the influence of ¡°sanp¨­-yoshi.¡± This principle, developed by the ?mi merchants between the 16th and 19th centuries, holds that transactions should benefit the seller, the buyer, and society.

Interestingly, the results also showed that early adopters paid lower audit and non-audit fees after reporting KAMs became mandatory. This implies that these companies were able to use the pilot period as a chance to disclose and mitigate audit risks.

Market response to audit transparency

Despite the additional costs, companies with higher ESG scores had better accounting and market performance on average in the years following mandatory KAMs implementation (2020-2023). While there is some evidence that the stricter standards increased firm performance overall, this effect was amplified for firms committed to sustainability and social responsibility. A high-ESG company tended to have higher stock returns and a better return on assets (ROA)¡ªhow profitable a firm is in relation to its total assets.

As the use of KAMs spread globally, these findings suggest that companies with established ESG practices are likely to receive the most benefits from more transparent auditing standards. ¡°The market appears to view ESG practices and KAMs reporting as a sort of two-factor authentication,¡± explained Semba. ¡°When companies with authentic sustainability practices invest heavily in transparent auditing, investors interpret it as credible signal of organizational strength.¡±

Publication

Maretno Agus Harjoto and Hu Dan Semba. (2025). Sustainability and financial disclosure: Role of ESG in key audit matters adoption. Managerial Auditing Journal, 1-38.

Funding

This research was supported by the Tsao Family Foundation and JSPS KAKENHI Grant Number JP22K01808.

Media contact

Alexander Evans
International Communications Office, ºÚÁϳԹÏÍø
icomm_research@t.mail.nagoya-u.ac.jp

Expert contact

Hu Dan Semba
Graduate School of Economics, ºÚÁϳԹÏÍø
ko.tan.n8@f.mail.nagoya-u.ac.jp

Top image

Researchers found that companies with strong sustainability practices benefit more from audit transparency. Markets appear to reward authentic commitment backed by rigorous disclosure. Credit: Kano Okada, ºÚÁϳԹÏÍø

ºÚÁϳԹÏÍø researchers develop first GeSn-based Group IV resonant tunneling diode that operates at room temperature.

In a world first, researchers at ºÚÁϳԹÏÍø in Japan have successfully developed a resonant tunnel diode (RTD) that operates at room temperature made entirely from Group IV semiconductor materials. The development of an RTD that operates at room temperature means the device could be deployed at scale for next-generation wireless communication systems. The use of only non-toxic Group IV semiconductor materials also supports more sustainable manufacturing processes.

This research marks a pivotal step toward terahertz wireless components that deliver unprecedented speed and data handling capacity with superior energy efficiency. ¡°Compared to InGaAs-based Group III-V RTDs that include toxic and rare elements, such as indium and arsenic, Group IV compounds-based RTDs are safer, lower cost, and offer advantages for creating integrated production processes,¡± said senior author Dr. Shigehisa Shibayama from the ºÚÁϳԹÏÍø . The results were published in the journal .

Terahertz waves and quantum devices

Researchers have long struggled to achieve the high-speed and large-volume data transfer needed for sixth-generation (6G) cellular networks. One promising solution is wireless communication using terahertz waves¡ªelectromagnetic waves that vibrate a trillion times per second, enabling ultra-high-speed data transmission. However, many technical challenges remain before this technology can be made practical for consumer applications.

A critical component for realizing terahertz communication is the RTD. This quantum device operates through negative differential resistance, a counterintuitive property where increasing voltage actually decreases current. When part of a properly designed circuit, this property allows the diodes to sustain high-frequency oscillations that would otherwise decay due to electrical losses.

Moving beyond laboratory constraints

The secret behind an RTD lies in its double-barrier structure, where electrons or holes tunnel through layers of different semiconductor materials, each only a few atoms thick. These layers have mainly been created from InGaAs-based Group III-V materials that include toxic and rare elements, such as indium and arsenic.

In previous research by the same group, the researchers created a p-type RTD using only Group IV materials, specifically germanium-tin (GeSn) and germanium-silicon-tin (GeSiSn) alloys. One limitation was that the diode only functioned at extremely low temperatures, around -263¡ãC. Since consumer electronics and wireless systems cannot practically reach this level of cooling, the device would have remained a laboratory curiosity.

Shibayama and his colleagues have now discovered how to use only Group IV materials to produce a p-RTD that functions at room temperatures of around 27¡ãC. This significant improvement opens new possibilities for the widespread adoption of terahertz semiconductor devices.

The research group achieved its breakthrough by introducing hydrogen gas during the layer formation process. They tested three different scenarios: 1) introducing hydrogen gas to both the two GeSiSn layers and three GeSn layers, 2) introducing no hydrogen gas, and 3) introducing hydrogen gas to only the three GeSn layers. In the last scenario, hydrogen gas restricted island growth and mixing between layers, resulting in a smooth and well-ordered double-barrier structure.

¡°The RTD cannot function if these layers are mixed,¡± said Dr. Shibayama. ¡°If there are defects in the layers, electrons can tunnel through these easier routes, leading to current leakage. This leakage current needs to be reduced for negative differential resistance¡ªthe key property of an RTD¡ªto occur.¡±

Publication:
Shota Torimoto, Shuto Ishimoto, Yoshiki Kato, Mitsuo Sakashita, Masashi Kurosawa,
Osamu Nakatsuka, & Shigehisa Shibayama. (2025). Room temperature operation of Ge_1?xSn_x/Ge_1?x?ySi_xSn_y resonant tunneling diode featured with H₂-introduction during molecular beam epitaxy. ACS Applied Electronic Materials, 7(16), 7688¨C7696.

Funding:
This research was supported in part by JST PRESTO (Grant Number JPMJPR21B6) and JST CREST (Grant Number JPMJCR21C2).

Expert contact:
Shigehisa Shibayama
ºÚÁϳԹÏÍø, Graduate School of Engineering
s-shibayama@nagoya-u.jp

Media contact:
Alexander Evans
ºÚÁϳԹÏÍø, International Communications Office
icomm_research@t.mail.nagoya-u.ac.jp

Top image: Assistant Professor Shigehisa Shibayama (right) and first author Shota Torimoto (left), along with the rest of the team, have developed a resonant tunneling diode using only non-toxic Group IV semiconductor materials that operates at room temperature. Credit: Shigehisa Shibayama (ºÚÁϳԹÏÍø) and Shota Torimoto (ºÚÁϳԹÏÍø)