Thursday, May 22, 2025

Rubber that resists cracking

Improved process makes material 10 times stronger

Harvard John A. Paulson School of Engineering and Applied Sciences

Rubber tanglemer — video:
Harvard researchers have developed a new way to produce natural rubber that endows the material with higher crack resistance and durability.
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Credit: Harvard SEAS

Natural rubber, one of the world's most widely manufactured biomaterials, has been used by humans for thousands of years. Its resistance to crack growth, however, hasn't improved much for decades.

Until now. Materials researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have devised a way to produce natural rubber that retains its key properties of stretchiness and durability while greatly improving its ability to resist cracking, even after repeated cycles of use.

The work is published in Nature Sustainability and is led by Zhigang Suo, the Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at SEAS.

“Improving crack resistance will extend the material’s service lifetime and therefore improve its sustainability,” said first author and former SEAS postdoctoral researcher Guodong Nian.

Natural rubber is a durable polymer material that’s in too many products to count: gloves, tires, shoes, medical devices, conveyor belts.

Derived from natural rubber latex, a milk-like substance from the Hevea tree, rubber is harvested, coagulated, dried, mixed with additives, shaped, and heated to trigger vulcanization. This process creates short polymer chains within the material that are densely crosslinked, or chemically bonded.

The researchers modified this longstanding, high-intensity process to induce a gentler transformation that retains long polymer chains in their natural state, rather than cutting them into shorter chains. Resembling tangled spaghetti, their so-called rubber “tanglemer” endows the new product with heightened durability by outnumbering crosslinks with entanglements.

“We used a low-intensity processing method, based on latex processing methods, that preserved the long polymer chains,” Nian said.

When a crack forms in the new material, the long spaghetti strands spread out the stress by sliding past each other, allowing more rubber to crystallize as it stretches, and overall making the material stronger and more resistant to cracking.

Their results blew away their expectations, said paper co-first author Zheqi Chen, a former SEAS postdoctoral researcher. The rubber became four times better at resisting slow crack growth during repeated stretching. It became 10 times tougher overall.

“We imagined that the properties would be enhanced maybe twice or three times, but actually they were enhanced by one order of magnitude,” Chen said.

The work highlights the benefit of preserving the natural state of long polymer chains. But issues remain: the new material processing involves a large amount of water evaporation, yielding a smaller volume of material than would be desirable for products like tires. It is currently more suited to thin rubber products like gloves or condoms. Other possibilities the new process opens up are flexible electronics or soft robotics parts.

The paper was co-authored by Xianyang Bao (co-first), Matthew Wei Ming Tan, and Yakov Kutsovsky. The research had federal support from the National Science Foundation under the Materials Research Science and Engineering Centers (DMR-2011754) and the Air Force Office of Scientific Research under award No. GA9550-20-1-0397.

Learn more: https://www.youtube.com/watch?v=UvGIVUFnsjg

In the new rubber tanglemer, a long polymer strand at a crack tip de-concentrates stress over a long distance, making the material more resistant to crack growth than regular natural rubber.

Credit

Suo Lab / Harvard SEAS

Journal

Nature Sustainability

DOI

10.1038/s41893-025-01559-z

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Natural rubber with high resistance to crack growth

Article Publication Date

7-May-2025

New low-cost laser technique could make cataract surgery more accessible worldwide

A low-cost, diode-based laser system safely and precisely emulsifies cataract tissue, offering a potential alternative to expensive femtosecond laser technology

SPIE--International Society for Optics and Photonics

image:
Laser phacoemulsification of cataracts uses a custom diode laser system to deliver the laser light directly to the target.
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Credit: Mitchell Harrah.

Cataracts remain one of the leading causes of blindness around the world, especially in countries where access to advanced medical equipment is limited. Standard treatment involves a technique called phacoemulsification, which uses ultrasound or laser energy to break up and remove the cloudy lens in the eye. While modern laser-based versions of this surgery can improve healing and accuracy, they rely on expensive equipment that is out of reach for many low- and middle-income countries. This leaves patients in these regions with few options, often resulting in longer recovery times and poorer outcomes.

As reported in Biophotonics Discovery, a research team from the University of South Florida has introduced a new approach that could help address this gap in global eye care. In a recent study, the team demonstrated a method for removing cataracts using a low-cost, millisecond-pulsed laser system built from commercially available diode lasers. Unlike the high-powered femtosecond lasers typically used in wealthier healthcare systems, this system is far more affordable and compact.

Using both computer models and physical tests on tissue-mimicking materials, the researchers showed that their laser technique can effectively liquefy cataract-like material without damaging surrounding tissue. The heating effect of the laser is tightly controlled and limited to the point of contact, reducing the risk of unintended harm.

Mitchell Harrah, a PhD candidate and lead author on the study, explains that the system uses pulses of near-infrared light delivered through a custom-built surgical probe. Their experiments suggest that this design could be a practical alternative to traditional laser phacoemulsification in settings where high-tech equipment is not available.

If further validated in clinical settings, this technology could significantly reduce the cost and complexity of cataract surgery. That would help bring sight-saving treatment to millions of people who currently lack access—especially in rural areas or low-income countries where the burden of cataracts is growing rapidly with aging populations.

The team hopes this proof-of-concept study will pave the way for clinical testing and broader adoption of the technique in the coming years.

For details, see the original Gold Open Access article by M. Harrah et al., “Low-cost optical system for laser phacoemulsification of cataracts,” Biophotonics Discovery 2(2), 022304, doi: 10.1117/1.BIOS.2.2.022304.

Journal

Biophotonics Discovery

DOI

10.1117/1.BIOS.2.2.022304

Article Title

Low-cost optical system for laser phacoemulsification of cataracts

3D printers leave hidden ‘fingerprints’ that reveal part origins

University of Illinois Grainger College of Engineering

A new artificial intelligence system pinpoints the origin of 3D printed parts down to the specific machine that made them. The technology could allow manufacturers to monitor their suppliers and manage their supply chains, detecting early problems and verifying that suppliers are following agreed upon processes.

A team of researchers led by Bill King, a professor of mechanical science and engineering at the University of Illinois Urbana-Champaign, has discovered that parts made by additive manufacturing, also known as 3D printing, carry a unique signature from the specific machine that fabricated them. This inspired the development of an AI system which detects the signature, or “fingerprint,” from a photograph of the part and identifies its origin.

“We are still amazed that this works: we can print the same part design on two identical machines –same model, same process settings, same material – and each machine leaves a unique fingerprint that the AI model can trace back to the machine,” King said. “It’s possible to determine exactly where and how something was made. You don’t have to take your supplier’s word on anything.”

The results of this study were recently published in the Nature partner journal Advanced Manufacturing.

The technology has major implications for supplier management and quality control, according to King. When a manufacturer contracts a supplier to produce parts for a product, the supplier typically agrees to adhere to a specific set of machines, processes, and factory procedures and not to make any changes without permission. However, this provision is difficult to enforce. Suppliers often make changes without notice, from the fabrication process to the materials used. They are normally benign, but they can also cause major issues in the final product.

“Modern supply chains are based on trust,” King said. “There’s due diligence in the form of audits and site tours at the start of the relationship. But, for most companies, it’s not feasible to continuously monitor their suppliers. Changes to the manufacturing process can go unnoticed for a long time, and you don’t find out until a bad batch of products is made. Everyone who works in manufacturing has a story about a supplier that changed something without permission and caused a serious problem.”

While studying the repeatability of 3D printers, King’s research group noticed that the tolerances of part dimensions were correlated with individual machines. This inspired the researchers to examine photographs of the parts. It turned out that it is possible to determine the specific machine made the part, the fabrication process, and the materials used – the production “fingerprint.”

“These manufacturing fingerprints have been hiding in plain sight,” King said. “There are thousands of 3D printers in the world, and tens of millions of 3D printed parts used in airplanes, automobiles, medical devices, consumer products, and a host of other applications. Each one of these parts has a unique signature that can be detected using AI.”

King’s research group developed an AI model to identify production fingerprints from photographs taken with smartphone cameras. The AI model was developed on a large data set, comprising photographs of 9,192 parts made on 21 machines from six companies and with four different fabrication processes. When calibrating their model, the researchers found that a fingerprint could be obtained with 98% accuracy from just 1 square millimeter of the part’s surface.

“Our results suggest that the AI model can make accurate predictions when trained with as few as 10 parts,” King said. “Using just a few samples from a supplier, it’s possible to verify everything that they deliver after.”

King believes that this technology has the potential to overhaul supply chain management. With it, manufacturers can detect problems at early stages of production, and they save the time and resources needed to pinpoint the origins of errors. The technology could also be used to track the origins of illicit goods.

Miles Bimrose, Davis McGregor, Charlie Wood and Sameh Tawfick also contributed to this work.

The study, “Additive Manufacturing Source Identification from Photographs using Deep Learning,” is available online. DOI: 10.1038/s44334-025-00031-2

Journal

npj Advanced Manufacturing

DOI

10.1038/s44334-025-00031-2

Article Title

Additive manufacturing source identification from photographs using deep learning

Article Publication Date

17-May-2025

RSV infections in children requiring primary care lead to significant economic impact

Impact is driven by outpatient healthcare costs and parental work absences, with disparities in costs between countries and implications for immunization strategies

European Centre for Disease Prevention and Control (ECDC)

Infections from respiratory syncytial virus (RSV) in children requiring primary care led to significant societal economic costs from outpatient treatment and parental work absences in Europe, according to a study just published on Eurosurveillance.

The study sought to provide insights for public health policy and support costs and benefits analyses for RSV immunisation strategies. RSV infections are a leading cause of acute respiratory infections in children, with nearly all children experiencing at least one RSV infection by the age of 2. While some children develop a severe form of RSV disease that might require hospitalisation, most infections are managed in primary care.

Significant disparities in societal costs across age groups and countries

The study enrolled 3,414 children under the age of 5 with acute respiratory infection in Belgium, Italy, the Netherlands, Spain, and the United Kingdom (UK), of which 33% tested positive for RSV. Children were recruited through primary care physicians for RSV seasons 2020/21 (UK only), 2021/22 and 2022/23. Among children diagnosed with RSV, the cost of primary care treatment and parental work absences were assessed over 30 days through questionnaires filled in by parents. The calculation of overall economic burden comprised outpatient healthcare costs and missed work days by parents, with results stratified by country and by age the group of children diagnosed with RSV.

Researchers found that the RSV infections resulted in a significant economic burden, with costs varying substantially between the five countries taking part in this study: average outpatient healthcare costs per RSV episode ranged from 97 EUR in the Netherlands to 300 EUR in Spain, and were mostly driven by primary care visits. The costs for parental absence from work ranged from 454 EUR in the UK to 994 EUR in Belgium.

The main sources of costs were repeated visits to primary care physicians and parents missing work to care for their sick children. Costs related to healthcare were higher for infants under the age of 1, while work absences among parents represented a higher proportion of costs among children between 1 to 5 years of age. Medication costs to treat RSV infections contributed the least to the overall economic burden across all countries and age groups.

The mean number of primary care visits per child varied from 1.4 in the Netherlands to 3.0 in Spain. There were wide disparities in hospitalisation rates, which ranged from 4% of infections leading to hospitalisation in the Netherlands and Italy to 44% in Belgium. However, this may have been due to the fact that Belgium included data on children in out-of-hours care. The proportion of children being prescribed medication ranged from 26% in the UK to 77% in Italy. Parental work absences varied considerably between countries, and ranged from 13% of parents reporting absences and a mean of 1.3 missed working days in Spain to 71% of parents missing work days with a mean of 4.1 days off in Belgium.

The study has some limitations. There may have been some selection bias by physicians in selecting children and the study only included costs within 30 days of the first doctor visit. The COVID-19 pandemic could also have affected data. While evidence suggests that self-reported work absence serves as a valid alternative to documented work absence, some assumptions were made in the data analysis due to incomplete information. Finally, based on existing research, all costs were assumed to be related to RSV regardless of possible infections with other viruses.

Findings crucial to define immunisation strategies

The disparities revealed in the data highlight the importance of considering country-specific cost estimates when defining RSV immunisation strategies. These can vary widely due to differences in healthcare systems, care-seeking behaviour and parental leave policies.

This study also addresses a critical gap in understanding the overall economic impact of childhood RSV infections, as most studies on the economic burden of RSV so far have focused on the costs associated with RSV-related hospitalisation and not included costs from primary care. While infections treated in primary care have lower healthcare costs, they still contribute significantly to the overall economic burden of RSV.

“Our findings are particularly timely in light of the recent introduction of RSV immunisation strategies for infants, and the ongoing development of several RSV vaccines for toddlers and older children,” the authors stated.

Journal

Eurosurveillance

DOI

10.2807/1560-7917.ES.2025.30.20.2400797

Method of Research

Observational study

Subject of Research

People

Article Title

Economic impact of RSV infections in young children attending primary care: a prospective cohort study in five European countries, 2021 to 2023

Article Publication Date

22-May-2025

Sounding out coral larval settlements #ASA188

Coral larvae are attracted to areas with other healthy coral structures, using cues like sound to seek them out

Acoustical Society of America

Natalie Levy counts settled coral larvae with an ultraviolet light — image:
Natalie Levy, a post-doctoral researcher, counts settled coral larvae with an ultraviolet light on the synthetically coated microhabitat structures.
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Credit: O. Boulais

NEW ORLEANS, May 22, 2025 – Coral reefs are vital to marine biodiversity, but their livelihood is under threat due to climate instability and the impacts of human activities.

Rehabilitating marine environments requires innovative solutions. Océane Boulais, a doctoral student at the Scripps Institution of Oceanography, studies one of these potential solutions: the impacts of acoustics on coral larval recruitment and settlement.

After spawning, coral larvae drift or swim through the water column, seeking suitable sites to find a home to attach to along the ocean floor.

“Multiple chemical compounds have already been identified as environmental cues that stimulate this settling behavior, presumably by indicating to the larvae when other successful-settled coral structures are nearby,” said Boulais. “A growing body of evidence over the past 20 years is also finding that sound may be another such cue.”

Healthy reefs are acoustically rich environments, filled with fish croaks and shrimp snaps. Boulais and their collaborators mimicked these sound environments to study the effects of sounds on 19 artificial coral settlement modules placed in Kāneʻohe Bay, Oahu, Hawaii. The researchers recorded audio near a vibrant reef, which they replayed at various distances from their artificial microhabitats. The artificial microhabitats were coated with a bacteria designed to induce larval settlement, creating a suitable habitat for attracting coral larvae.

Boulais will present details on their findings about the impacts sound has on coral larvae Thursday, May 22, at 9:20 a.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23. Notably, there were significant increases in coral settlement close to the speakers.

The researchers are planning an additional data deployment in the summer of 2025. Boulais said they hope to ultimately develop scalable strategies to study larger reef structures with audiovisual remote sensing tools, using low-cost cameras for continuously monitoring the reef’s biodiversity.

“Innovative, interdisciplinary approaches — combining science, technology, and creativity — can offer powerful solutions to pressing environmental challenges like coral reef degradation,” Boulais said. “Ultimately, I hope this research inspires both urgency and hope for the future of coral reefs.”

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Study finds unfair expectations place extra pressure on new teachers

‘Classroom readiness’ is a policy slogan that fails to reflect real-world teaching challenges, a new study fin

Taylor & Francis Group

Experts say standardised tests do not guarantee new teachers can handle classroom complexities and may increase the risk of burnout.
Reforms in teacher education, mentorship and ongoing development matter more than rigid assessments, according to researchers.

Teaching shortages internationally could be worsened by unrealistic expectations placed on new graduates, a new study by QUT researchers reveals.

Published in the peer-reviewed Asia-Pacific Journal of Teacher Education, the QUT study reveals that the term ‘classroom readiness’ has become a convenient policy tool rather than a reliable measure of teacher capability.

Researchers say that teaching performance assessments, which are often used to evaluate new teachers, fail to account for the real-world complexities of teaching.

Schools continue to report high levels of teacher burnout and high attrition rates among teachers caused by factors such as teacher shortages, which is beyond the control of teacher education.

The research, led by Associate Professor Rebecca Spooner-Lane and including Associate Professor, Nerida Spina, Ms Elizabeth Briant and Dr Julia Mascadri all from the QUT School of Education, questions whether education boards are measuring the wrong thing by expecting new teachers to meet rigid standards while neglecting the practical and humanistic challenges of the profession.

Associate Professor Spooner-Lane, who specialises in research focused on the professional development and career progression of teachers from graduate teacher through to lead teacher, said ‘classroom readiness’ was more of a policy construct than a genuine assessment of teaching capability.

“The term classroom readiness has been used strategically to justify reforms in teacher education, but our research shows that readiness is not a point-in-time achievement, it’s a professional journey,” she said.

“Our review found that readiness is too multifaceted to be effectively measured by a single assessment.

“While teaching performance assessments aim to standardise and regulate teacher preparation, they risk oversimplifying the demands teachers face in diverse classroom settings.”

The paper says that policies enforcing assessments assume graduates can seamlessly transition into classroom teaching, with evidence that even top performing teachers struggle in their first years without proper support.

“New teachers often enter classrooms facing unrealistic expectations, and are required to manage complex student needs, adapt to curriculum changes and navigate classroom challenges with minimal guidance,” Associate Professor Sponer-Lane said.

“Assessments reduce teacher preparation to a selected set of criteria, ignoring the mentorship, adaptability and professional development needed to thrive.”

In Australia for example, it is assumed that passing an assessment guarantees classroom readiness, but school leaders report that many graduates still require significant training to navigate the profession effectively.

Associate Professor Nerida Spina, co-author of the study, said there was an urgent need to ensure new teachers were well prepared in their initial teacher education degrees, and then well supported once they started work into the profession.

“We cannot expect graduating teachers to step into classrooms as fully-fledged experts from day one,” she said.

“They require structured support systems that guide their early years in the profession, helping them build confidence and competence.

“A teacher’s journey should be one of continuous development, shaped by meaningful mentorship and accessible opportunities for learning. Without these, new educators may struggle to navigate the complexities of real-world teaching.

“Standardised testing alone does not prepare teachers for the realities of the classroom. Instead, we must invest in hands-on training, professional collaboration, and real-world teaching experiences that truly equip them for success.”

Journal

Asia-Pacific Journal of Teacher Education

DOI

10.1080/1359866X.2025.2494727

Method of Research

Literature review

Article Title

A scoping review of classroom readiness: what is it? Can it (and should it) be assessed?

Climate change: Penguin guano may help reduce effects of climate change in Antarctica

Springer Nature

Ammonia released from penguin guano may help to reduce the effects of climate change in the Antarctic by contributing to increased cloud formation, according to an analysis published in Communications Earth & Environment. The conclusion is the result of measurements taken downwind of a colony of Adelie penguins (Pygoscelis adeliae).

Antarctic ecosystems are facing significant pressures because of human-driven climate change, including a recent decreasing trend in the area covered by sea ice. Penguins are key species in the Antarctic ecosystem whose habitat is threatened by this ongoing ice loss. They are also, along with other seabirds, major emitters of ammonia in the region. Ammonia can increase cloud formation by reacting with gases containing sulphur to increase the creation of aerosols — particles which give water vapour a surface to condense upon, leading to cloud formation. The resulting clouds can act as insulating layers in the atmosphere, often helping to reduce surface temperatures and subsequently affecting the extent of sea ice coverage. However, the specific interaction between penguins and the Antarctic climate is currently poorly understood.

Matthew Boyer, Mikko Sipilä, and colleagues measured the concentration of ammonia in the air at a site near Marambio Base, Antarctica, between 10 January and 20 March 2023. They observed that when the wind blew from the direction of a 60,000-individual Adelie penguin colony around 8 kilometres away, the ammonia concentration increased to as high as 13.5 parts per billion — more than 1,000 times higher than the baseline value (less than 10.5 parts per trillion). Even after the penguins migrated from the area towards the end of February, the ammonia concentration was still more than 100 times higher than the baseline, as the penguin guano left at the colony site continued to emit the gas.

To confirm that the increase in ammonia concentration affected aerosol particle concentration, the authors recorded several additional atmospheric measurements on a single day. When the wind blew from the penguin colony, the number, and size, of aerosol particles recorded at the site sharply increased, with the authors later (approximately three hours after the wind changed) observing a period of fog which they say was likely a result of the increased aerosol particle concentration.

The results suggest that penguin guano may be helping to reduce the effects of climate change on the penguins’ own habitat of Antarctica. The authors say that their work emphasises the importance, and benefits, of protecting seabirds and their habitats from the effects of climate change.

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Springer Nature is committed to boosting the visibility of the UN Sustainable Development Goals and relevant information and evidence published in our journals and books. The research described in this press release pertains to SDG 13 (Climate Actions) and SDG 15 (Life on Land). More information can be found here.

Journal

Communications Earth & Environment

DOI

10.1038/s43247-025-02312-2

Method of Research

Observational study

Subject of Research

Animals

Article Title

Penguin guano is an important source of climate-relevant aerosol particles in Antarctica

Article Publication Date

22-May-2025