Green ammonia powered by sunlight

A process mimicking aspects of photosynthesis produces ammonia efficiently

University of Tokyo

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When the reaction takes place in optimal conditions, two nitrogen atoms and three water molecules form two ammonia molecules with only oxygen left over. ©2025 Nishibayashi et al. CC-BY-ND

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Credit: ©2025 Nishibayashi et al. CC-BY-ND

Ammonia is a chemical essential to many agricultural and industrial processes, but it’s mode of production comes with an incredibly high energy cost. Various attempts have, and are, being made to produce ammonia more efficiently. For the first time, a group including researchers from the University of Tokyo combined atmospheric nitrogen, water and sunlight, and using two catalysts, produced sizable quantities of ammonia without a high energy cost. Their processes mirror natural processes found in plants utilizing symbiotic bacteria.

You’ve probably heard of ammonia, especially in relation to agriculture, where it’s an essential component of the fertilizers that feed the crops upon which all our lives depend. But here are some numbers to paint a picture of why ammonia is so important and impactful: Just under 200 million tons of ammonia are produced yearly, and 80% of this is used for fertilizer. Also, its production accounts for around 2% of the world's entire energy consumption and correspondingly around 2% of the world's entire carbon dioxide emissions. With these things in mind, it’s understandable why researchers around the world are trying to create a cleaner, more efficient means to produce ammonia.

Professor Yoshiaki Nishibayashi from the Department of Applied Chemistry at the University of Tokyo and his team have recently made significant strides in this goal. They succeeded in developing a novel catalytic system for producing ammonia from abundant molecules found on Earth, including atmospheric nitrogen and water. The key lies in a combination of two kinds of catalysts, intermediate compounds which enable or speed up reactions without contributing to the final mixture, made especially for ammonia production, and which are driven by sunlight.

“This is the first successful example of photocatalytic ammonia production using atmospheric dinitrogen as a nitrogen source and water as a proton source, that also uses visible light energy and two kinds of molecular catalysts,” said Nishibayashi. “We used an iridium photocatalyst and another chemical called a tertiary phosphine which enabled photochemical activation of water molecules. The reaction efficiencies were higher than expected, compared to previous reports of visible light-driven photocatalytic ammonia formation.”

The thing about chemical reactions is, they don’t always happen as fast as you want, or in the way that you want. And to control the outcome, efficiency, timing and so on of a process, you need to involve additional components beyond just the raw ingredients. This is where the catalysts come in. Nishibayashi and his team utilized two catalysts for these experiments, one based on the transition metal molybdenum for the activation of dinitrogen and the other based on the transition metal iridium for the photoactivation of both tertiary phosphines and water. A third component called tertiary phosphines are also key to helping get the protons out of water molecules.

“When the iridium photocatalyst absorbs sunlight, its excited state can oxidize the tertiary phosphines. The oxidized tertiary phosphines then activate water molecules via formation of a chemical bond between the phosphine’s phosphorous atom and the water, yielding protons,” said Nishibayashi. “The molybdenum catalyst then enables nitrogen to bond with these protons to become ammonia. The use of water for producing dihydrogen or hydrogen atoms is one of the most important processes for achieving green ammonia production.”

The team managed to produce this reaction at a scale 10 times that of previous experiments, suggesting it’s ready for trials at larger scales, though there are still some issues that could improve the safety and effectiveness further. Some of the components such as the tertiary phosphines could be made using solar power or recycled from phosphine oxides. And while stable themselves, they may be toxic if ingested by people, so it would be ideal to find a responsible way to dispose of or recycle them.

“In plants, ammonia is formed by biological nitrogen fixation using cyanobacteria and is linked with photosynthesis,” said Nishibayashi. “Here, the electrons for the reaction are supplied by photosynthesis and protons are derived from water. Therefore, the findings of our recent study can be regarded as a successful example of the artificial photosynthesis of ammonia.”

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Journal article: Yasuomi Yamazaki, Yoshiki Endo, Yoshiaki Nishibayashi, “Catalytic ammonia formation from dinitrogen, water, and visible light energy”, Nature Communications, DOI: 10.1038/s41467-025-59727-w, https://www.nature.com/articles/s41467-025-59727-w

Funding: We acknowledge the Grants-in-Aid for Scientific Research (Nos. 20H05671, 24H00049, 24H01834, and 24K21778 to Y.N.; JP23H03832, JP23H03830, and 24K08441 to Y.Y.) from JSPS and MEXT. This paper is based on results obtained from a project, JPNP 21020, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

 

About The University of Tokyo:

The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 5,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on X (formerly Twitter) at @UTokyo_News_en.

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Journal

Nature Communications

DOI

10.1038/s41467-025-59727-w 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Catalytic ammonia formation from dinitrogen, water, and visible light energy

Article Publication Date

22-May-2025

 

Infrared contact lenses allow people to see in the dark, even with their eyes closed

Cell Press

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Study participant putting contacts in

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Credit: Yuqian Ma, Yunuo Chen, Hang Zhao

Neuroscientists and materials scientists have created contact lenses that enable infrared vision in both humans and mice by converting infrared light into visible light. Unlike infrared night vision goggles, the contact lenses, described in the Cell Press journal Cell on May 22, do not require a power source—and they enable the wearer to perceive multiple infrared wavelengths. Because they’re transparent, users can see both infrared and visible light simultaneously, though infrared vision was enhanced when participants had their eyes closed.  

“Our research opens up the potential for non-invasive wearable devices to give people super-vision,” says senior author Tian Xue, a neuroscientist at the University of Science and Technology of China. “There are many potential applications right away for this material. For example, flickering infrared light could be used to transmit information in security, rescue, encryption or anti-counterfeiting settings.” 

The contact lens technology uses nanoparticles that absorb infrared light and convert it into wavelengths that are visible to mammalian eyes (e.g., electromagnetic radiation in the 400-700 nm range). The nanoparticles specifically enable detection of “near-infrared light,” which is infrared light in the 800-1600 nm range, just beyond what humans can already see. The team previously showed that these nanoparticles enable infrared vision in mice when injected into the retina, but they wanted to design a less invasive option.  

To create the contact lenses, the team combined the nanoparticles with flexible, non-toxic polymers that are used in standard soft contact lenses. After showing that the contact lenses were non-toxic, they tested their function in both humans and mice. 

They found that contact lens-wearing mice displayed behaviors suggesting that they could see infrared wavelengths. For example, when the mice were given the choice of a dark box and an infrared-illuminated box, contact-wearing mice chose the dark box whereas contact-less mice showed no preference. The mice also showed physiological signals of infrared vision: the pupils of contact-wearing mice constricted in the presence of infrared light, and brain imaging revealed that infrared light caused their visual processing centers to light up.  

In humans, the infrared contact lenses enabled participants to accurately detect flashing morse code-like signals and to perceive the direction of incoming infrared light. “It's totally clear cut: without the contact lenses, the subject cannot see anything, but when they put them on, they can clearly see the flickering of the infrared light,” said Xue. “We also found that when the subject closes their eyes, they’re even better able to receive this flickering information, because near-infrared light penetrates the eyelid more effectively than visible light, so there is less interference from visible light.”  

An additional tweak to the contact lenses allows users to differentiate between different spectra of infrared light by engineering the nanoparticles to color-code different infrared wavelengths. For example, infrared wavelengths of 980 nm were converted to blue light, wavelengths of 808 nm were converted to green light, and wavelengths of 1,532 nm were converted to red light. In addition to enabling wearers to perceive more detail within the infrared spectrum, these color-coding nanoparticles could be modified to help color blind people see wavelengths that they would otherwise be unable to detect. 

“By converting red visible light into something like green visible light, this technology could make the invisible visible for color blind people,” says Xue. 

Because the contact lenses have limited ability to capture fine details (due to their close proximity to the retina, which causes the converted light particles to scatter), the team also developed a wearable glass system using the same nanoparticle technology, which enabled participants to perceive higher-resolution infrared information.   

Currently, the contact lenses are only able to detect infrared radiation projected from an LED light source, but the researchers are working to increase the nanoparticles’ sensitivity so that they can detect lower levels of infrared light.  

“In the future, by working together with materials scientists and optical experts, we hope to make a contact lens with more precise spatial resolution and higher sensitivity,” says Xue.  

Preparation procedures for infrared contacts.

Credit

Sheng Wang

Researcher places infrared contacts in participant's eyes.

Credit

Yuqian Ma, Yunuo Chen, Hang Zhao

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This research was supported by the Science and Technology Innovation 2030 Major Program, the National Key Research and Development Program of China, the Natural Science Foundation, the CAS Project for Young Scientists in Basic Research, the Major Scientific and Technological Program of Anhui Province, the Anhui Provincial Natural Science Foundation, the New Cornerstone Science Foundation the Feng Foundation of Biomedical Research, and the Human Frontier Science Program. 

Cell, Ma et al., “Near-infrared spatiotemporal color vision in humans enabled by upconversion contact lenses.” https://www.cell.com/cell/fulltext/S0092-8674(25)00454-4

Cell (@CellCellPress), the flagship journal of Cell Press, is a bimonthly journal that publishes findings of unusual significance in any area of experimental biology, including but not limited to cell biology, molecular biology, neuroscience, immunology, virology and microbiology, cancer, human genetics, systems biology, signaling, and disease mechanisms and therapeutics. Visit: http://www.cell.com/cell. To receive Cell Press media alerts, contact press@cell.com.  

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Journal

Cell

DOI

10.1016/j.cell.2025.04.019 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Near-Infrared Spatiotemporal Color Vision in Humans Enabled by Upconversion Contact Lenses

Article Publication Date

22-May-2025

 

Why we trust people who grew up with less

Modest childhoods inspire more trust than privileged upbringings, study says

American Psychological Association

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When deciding whom to trust, people are more likely to choose individuals who grew up with less money over those who went to private schools or vacationed in Europe, according to research published by the American Psychological Association.

"Trust is essential for healthy relationships. Without it, romantic partnerships can fail, workplaces can suffer and social divisions can grow,” said lead researcher Kristin Laurin, PhD, a psychology professor at the University of British Columbia. “But what makes people trust someone in the first place?”

To find out, researchers ran a series of experiments with more than 1,900 participants. They explored whether someone's social class—either while growing up or currently—affects how trustworthy they appear to strangers. 

The research was published in the Journal of Personality and Social Psychology.

In one experiment, participants were asked to play a trust game with what they thought were other real people but were actually fictional profiles. Each participant filled out a profile and received copies of profiles from their “group.” Some fake profiles described people who grew up with less money—like attending public school or working part-time. Others described more privileged backgrounds, such as going to private school or taking vacations in Europe.

In the game, participants (known as “trusters”) started with 10 raffle tickets for a drawing for two $100 gift cards. They had the option to transfer any number of these raffle tickets to one of the fictional players in their group (known as “trustees”). Trusters were told any tickets transferred to a trustee would then be tripled, and the trustee could decide to return any number of those tickets to the truster.

The study looked at trust as a behavior--putting oneself at the mercy of the other player. How many raffle tickets participants transferred to another player indicated how much they behaviorally trusted that player.

The study also looked at trust as an expectation—believing the other player would be trustworthy. Participants were asked “If you gave all 10 tickets to this person, they would have 30. How many do you think they would give back?”

In similar experiments, researchers adjusted the fake profiles to suggest trustees’ current socioeconomic status and asked participants to rate the morality of the other players. People tended to show more behavioral trust toward individuals from lower-income backgrounds, whether past or present. However, they only believed a player was more trustworthy when the player grew up in a lower-income household.

“Our research shows that people draw a clear line between someone's childhood and their current situation,” Laurin said. “They generally saw people who grew up in lower-class homes as more moral and trustworthy. While they sometimes acted as if they trusted people who are currently lower class, they didn’t always believe those people would honor that trust.”

These findings suggest that people might want to be strategic about how they present themselves in social situations where trust is a component. “If you’ve always been wealthy, for example, you might want to downplay that history and focus on the now, whereas if you’ve always struggled financially, making it clear that you grew up with humble roots might be more to your advantage,” she said.

Laurin noted that while the study shows a preference for trusting those from lower-income backgrounds, especially those who grew up that way, it didn’t ask whether those individuals are actually more trustworthy.

“We didn’t examine whether a person’s childhood or current class background actually influences their behavior,” she said. “That’s a question for future studies—especially to understand when trust is misplaced or when people miss chances to trust others fairly.”

Article: “Trust and Trust Funds: How Others Childhood and Current Social Class Context Influence Trust Behavior and Expectations,” by Kristin Laurin, PhD, Holly Engstrom, PhD, Toni Schmader, PhD, and Khai Qing Chua, MA, University of British Columbia; Nadav Klein, PhD, Institut Européen d'Administration des Affaires; and Stéphane Côté, PhD, University of Toronto. Journal of Personality and Social Psychology, published online May 22, 2025.

Contact: Kristin Laurin, PhD, can be contacted via email at klaurin@psych.ubc.ca.

The American Psychological Association, in Washington, D.C., is the largest scientific and professional organization representing psychology in the United States. APA’s membership includes  173,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance the creation, communication and application of psychological knowledge to benefit society and improve lives.

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Journal

Journal of Personality and Social Psychology

DOI

10.1037/pspi0000497 

Method of Research

Experimental study

Subject of Research

People

Article Title

Trust and Trust Funds: How Others Childhood and Current Social Class Context Influence Trust Behavior and Expectations

Article Publication Date

22-May-2025

 

How property owners can work to prevent flooding

Introducing a severe impacts approach to guide adaptation to pluvial floods in residential and public buildings

Linköping University

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Mattias Hjerpe, senior associate professor at the Department of Thematic Studies—Environmental Change at Linköping University and Sofie Storbjörk, associate professor at the Department of Thematic Studies—Environmental Change at Linköping University.

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Credit: Jonas Roslund

The risk of heavy rainfall and severe flooding increases with climate change. But property owners – regardless of size – often underestimate their own responsibility and are unaware of what preventive measures they can take themselves. In a new scientific article, researchers from Linköping University, Sweden, show how to go about preventive work.

Many property owners believe that it is the municipality’s responsibility to ensure that their houses do not get flooded in heavy rain. However, in many countries, including Sweden, owner-responsibility is a cornerstone of the adaption governance, and property owners are recognized as a key actor for the adaption work. 

“We need to increase awareness that the property owner has an important role and that there’s much that can be done that doesn’t involve renovating the entire property,” says Sofie Storbjörk, associate professor at the Department of Thematic Studies—Environmental Change at Linköping University.

Even large municipal property companies may be uncertain about how to go about preventive work. To find new ways of working, the research team has collaborated with four municipally owned companies in Sweden. These administer rental apartments or properties for various municipal activities in two medium-sized cities. In total, they are responsible for just over 2,300 buildings. The researchers’ proposals are presented in an article in the journal Building Research and Innovation. 

Studying flood risk maps, the researchers found that many of the buildings were located in places with a high risk of rising water levels. This was the case for about half of the rental properties and one third of the buildings used for preschools, nursing homes and similar operations. The researchers carried out on-site inspections at 604 buildings to look for design weaknesses. Among other things, it turned out that one third had openings at ground level and that up to half of the inspected buildings were at risk of wastewater getting into the basement because there were no backflow valves. Many also had open holes or cracks in the foundations or the facade.

The large number of problems made it difficult for housing companies to know how to proceed. The researchers then conducted several workshops with key actors to find new approaches. The participants had to make a list of the worst things that could happen in the case of a flood event. There were a limited number of points: injury to people, evacuation of tenants and damage to technical installations or other critical functions. These feared consequences were then linked to the weaknesses discovered in the buildings. Which of them would likely contribute to a worst-case scenario? This made it easier to prioritise the houses that should be worked on first and to assess which measures would have the best effect.

But even among the large housing companies there was a perception that the municipalities bear the main responsibility for the preventive work. The researchers then helped to analyse what the property owners themselves have the power to carry out. It turned out to be a lot. For example, they can move key operations from the basement, install watertight doors, install backflow valves, raise entrance thresholds, make sure the ground slopes away from the building, and reduce the number of hard-paved surfaces.

The researchers conclude that the best way to work is to start from the worst-case scenario and the weaknesses of the buildings concerned. They also think that it is important that both municipalities and the large housing companies are open about what measures they are taking. That would be very helpful for small property owners such as tenant-owned housing associations and homeowners. Another study published by the researchers in the journal Buildings shows, for example, that tenant-owned housing associations in Sweden greatly underestimate the risk of being affected by flooding, and that even those affected multiple times have not considered working preventively. A major contributing factor is ignorance.

“It will be much, much clearer what you can do if housing companies and municipalities start to inform people of what they have done. Then, as a layperson, you can copy it,” says Mattias Hjerpe, senior associate professor at the Department of Thematic Studies—Environmental Change at Linköping University.

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Journal

Building Research & Information

DOI

10.1080/09613218.2025.2489573 

Subject of Research

Not applicable

Article Title

Introducing a severe impacts approach to guide adaptation to pluvial floods in residential and public buildings

UnitedHealth falls after report it secretly paid nursing homes to reduce hospital transfers

By Reuters
 May 21, 2025 

The logo for UnitedHealth Group appears above a trading post on the floor of the New York Stock Exchange, Thursday, April 17, 2025. (AP Photo/Richard Drew)

UnitedHealth UNH.N shares fell in premarket trading on Wednesday after a Guardian report that the company made secret payments to nursing homes to reduce hospital transfers added to the troubles of the healthcare conglomerate.

The alleged action, part of a series of cost-cutting tactics, has saved the company millions, but at times risked residents’ health, the Guardian reported, citing an investigation.

UnitedHealth said in response that “the U.S. Department of Justice investigated these allegations, interviewed witnesses, and obtained thousands of documents that demonstrated the significant factual inaccuracies in the allegations.”

The company also said in an emailed statement that the DoJ declined to pursue the matter after reviewing all the evidence during its multi-year investigation.

The company’s stock has taken a beating after the Wall Street Journal recently reported that the U.S. Department of Justice had begun a criminal investigation into the company for potential Medicare fraud, which followed CEO Andrew Witty’s abrupt departure and the withdrawal of its 2025 forecast last week.

On Wednesday, UnitedHealth shares fell more than 8 per cent before paring losses and were last down 3 per cent at $311.59.

Separately, HSBC downgraded the stock to “reduce” from “hold,” and cut the price target to a street-low of $270.

“New CEO has opportunity to start on a clean(er) slate, but we see risk to earnings growth along with policy overhang,” HSBC analysts wrote in a note.

The company named former CEO Stephen Hemsley to the top job, counting on his experience to turn around the healthcare giant and steer it through the current crisis.

The brokerage said higher medical costs, pressure on drug pricing and its pharmacy benefit management unit, OptumRx, and a potential Medicaid funding cut, can upset the company’s recovery journey.

UnitedHealth has grappled with several major challenges over the last 12 months, including a cyberattack at its tech unit that affected some 190 million people, a report of an investigation into its Medicare billing practices, and an unexpected surge in medical costs that has hurt its bottom line.

“The news is only seemingly getting worse for UnitedHealth,” said Sahak Manuelian, managing director, global equity trading at Wedbush.

“This is kind of a tough situation for investors to come in and have any kind of confidence in putting money to work, so we’ll have to kind of wait and see how this plays itself out, unfortunately,” Manuelian said.

(Reporting by Sriparna Roy in Bengaluru; Additional reporting by Twesha Dikshit in Bengaluru; Editing by Anil D’Silva)

Amazon investors again reject all shareholder proposals

Also rejected was a proposal soliciting a report on warehouse working conditions

By Reuters
May 21, 2025 


Amazon.com investors at its annual meeting again rejected all outside shareholder resolutions, including three meant to address the online retail giant’s impact on climate change.

Voters approved the reelection of 12 directors and proposed executive compensation.

Shareholders put forth eight proposals, all of which Amazon encouraged investors to vote against. Last year, there were 14 resolutions and all failed to get sufficient votes to be enacted.

Among the eight this year were a proposal that would have required additional reporting on Amazon’s overall carbon emissions, another targeting the climate impact of data centers and one calling for further disclosure about packaging materials, particularly plastic.

Amazon said its existing disclosures are sufficient and that it is working towards reducing its environmental impacts.

Two other proposals aimed at the development of artificial intelligence software were also rejected.

One resolution would have had Amazon assess its board structure to consider how it might develop AI more responsibly, while the other would have required a report on data usage and collection around AI.

Seattle-based Amazon asserted that it is a leader in responsible AI development, and so no changes are needed.

Shareholders had also proposed that Amazon create a policy ensuring the separation of its CEO and board chair roles. The company already separates the two roles between CEO Andy Jassy and founder Jeff Bezos, but not as a mandatory policy. As CEO until 2021, Bezos had also held the chairmanship.

Shareholders voted against a resolution that would have required the company to create a report on risks presented by advertising, in an effort to keep it politically neutral. Also rejected was a proposal soliciting a report on warehouse working conditions, a perennial source of criticism of the company.

Jassy, during a question and answer session, said tariffs imposed on many imported goods by the Trump administration had not impacted sales.

“We also haven’t yet seen any meaningful average selling price increases,” he said. “When you have two million sellers, they’re not all going to take the same action,” he said, noting that some had increased prices while others kept prices static.

Amazon will later provide a full tally of the investor vote in a securities filing. Shares were down less than 1% on Wednesday to $203.20.

Greg Bensinger, Reuters