Finding treasures with physics: The fingerprint matrix

How do you find objects buried in sand or hidden in thick fog? A team from the Institut Langevin (Paris) and TU Wien (Vienna) has developed an astonishing method.

Vienna University of Technology

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image: 

Left: Artistic impression of metal spheres buried in small glass beads. Middle: Conventional ultrasound picture. Right: With the new technology, the positions of the metal spheres can be precisely determined.

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Credit: TU Wien / Arthur Le Ber

Can we reveal objects that are hidden in environments completely opaque to the human eye? With conventional imaging techniques, the answer is no: a dense cloud or layer of material blocks light so completely that a simple photograph contains no information about what lies behind it.

However, a research collaboration between the Institut Langevin and TU Wien has now shown that, with the help of innovative mathematical tricks, objects can be detected even in such cases – using what is known as the ‘fingerprint matrix’. The team tested the newly developed method on metal objects buried in sand and in applications in the field of medical imaging. A joint publication on this topic has just appeared in the journal Nature Physics.

Seeing and hearing means wave scattering

Whether we take a normal photo or use ultrasound to look inside the body – from a physical point of view, the same thing always happens when we create an image: a wave is sent to an object, the object reflects part of the wave, and the reflected portion reaches our eye – or a measuring device. This reflected wave can be used to determine where the object is located.

However, this normally only works if the object's surroundings are sufficiently transparent. “Otherwise, for example in a dense cloud or in murky water, the phenomenon of multiple scattering occurs,” explains Prof. Stefan Rotter from the Institute of Theoretical Physics at TU Wien. The wave is scattered not only by the object to be imaged, but also by the surrounding environment – often many times over, so that only a greatly altered wave can be registered, in which the object being sought can no longer be recognised.

“Instead of the object, all you see is a diffuse fog – this is a fundamental problem of imaging techniques, from sonar in submarines to imaging techniques in medicine,” says Lukas Rachbauer, one of the co-authors of the study.

First the fingerprint, then the image

To overcome this problem, the French-Austrian research team developed a novel method: first, a specific object is examined in an interference-free environment. Each object scatters waves in a very specific, characteristic way. This wave scattering fingerprint of the object can be described mathematically by a matrix – the so-called scattering matrix.

The object is then hidden in a highly scattering medium – for example, buried in sand. “When ultrasonic waves are sent into this sand, they are scattered by the sand, but some of the sound penetrates so far into the sand that it is also scattered by the buried object,” says Stefan Rotter. “We cannot see the object, but the backscattered ultrasonic wave that hits the microphones of the measuring device still carries information about the fact that it has come into contact with the object we are looking for in the sand.”

If, on the one hand, you know the unaltered scattering matrix, the ‘fingerprint matrix’ of the object, and, on the other hand, you measure the wave scattering generated by the hidden object in a multiple-scattering medium, then you can calculate the position of the object using a mathematical method developed by the research team.

“From the correlations between the measured reflected wave and the unaltered fingerprint matrix, it is possible to deduce where the object is most likely to be located, even if the object is buried,” explains Stefan Rotter.

Steel balls in sand and medical markers

The method was tested with steel balls in sand, but also in medical applications: to monitor the recurrence of breast cancer, so-called lesion markers are used, which are often difficult to image because they are overlaid by scattered signals. With the new method, they were easy to locate.

In addition, fingerprint matrix technology was used to measure muscle fibres – which is particularly important for the diagnosis of heart and muscle diseases.

“The concept of the fingerprint matrix is very generally applicable – not only for ultrasound, but also for detection with light,” says Stefan Rotter. “It opens up important new possibilities in all areas of science where a reflection matrix can be measured.” Some objects also change their ‘scattering fingerprint’ when certain physical parameters change – such as pressure or temperature. Such variables could be measured from a distance using the new method. This would be particularly exciting, for example, in the measurement of the human brain, where waves have to penetrate the highly scattering skull.

In collaboration with CNRS Innovation and the Patent & Licence Management Department at TU Wien, the fingerprint method has now also been submitted for patenting and taken up by a medical technology company.

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Journal

Nature Physics

DOI

10.1038/s41567-025-03016-2 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Detection and characterization of targets in complex media using fingerprint matrices

Article Publication Date

2-Oct-2025

 

Viewing teens more positively may help their school performance and strengthen family bonds

Society for Research in Child Development

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Western cultures tend to view teens as moody, irresponsible, and rebellious. However, in China and in other cultures, the teen years are viewed more positively and seen as a time of learning how to become responsible and fulfilling family obligations. Previous research shows that fulfilling family obligations is an important marker of maturity and that as adolescents continue to improve their skills, they can contribute more to their families. 

Past studies also show that when teens are seen in a more positive light, they tend to do better in school. They are also more engaged, use self-regulated learning strategies and stay motivated. Researchers from Northwestern University, The University of Texas at Austin in the United States and Fudan University in China, were specifically interested in how Chinese middle schoolers’ beliefs about the teen years may influence their academic functioning and the quality of parent-teen bonds.

The study was comprised of 554 Chinese middle schoolers ages 13-14 years old, 50% boys and 50% girls. Participants were recruited from three middle schools in Shanghai. Families were primarily from middle- and working-class backgrounds with 49% of mothers and 52% of fathers having an associate degree or above. For one year, researchers tracked the students through completed online surveys completed by teens. The surveys measured teens’ general views about the teen years, as well as their self-expectation of becoming a responsible family member, their ability to delay immediate fun for academic tasks, their motivation after academic failures, and attachment bonds with their parents. 

The research showed that teens who held positive general views of their age group were more likely to believe they should help their parents. Additionally, teens who embraced family responsibilities (such as respecting parents and completing daily chores) also prioritized schoolwork. These teens were also more driven to make improvements after receiving poor grades and had more trust and connection with their parents.  

These findings suggest the importance of helping families learn how to view adolescence as a time of growing responsibility as this may benefit both families and schools. Parents should encourage their teens to contribute at home, while schools can support their resilience and motivation. The findings are not limited to the Chinese context. Practitioners and program developers around the world can also help by promoting messages that highlight young people’s potential rather than reinforcing negative stereotypes.

This research was featured in a new Child Development article, “Viewing Teens as Responsible in Family: Implications for Chinese Youth’s Academic and Social Adjustment,” by Dr. Beiming Yang, Varun Devakona, and Dr. Yang Qu from Northwestern University, Zexi Zhou from The University of Texas at Austin and Dr. Bin-Bin Chen from Fudan University. 

 The Society for Research in Child Development (SRCD) had the opportunity to speak with the author team to learn more about the research. 

SRCD: Did anything in the results surprise you? 

Author team:  A key surprise for us was the consistent and parallel impact that teen’s general views of adolescence had across two very different, and often separately studied, domains of their life: their academic functioning and their social relationships. One might assume that the factors driving academic success differ from those that foster strong family bonds. However, we found that the same underlying mechanism, which was teen’s personal sense of responsibility to their parents, predicted positive outcomes in both domains simultaneously. Parents are often worried about teens’ school disengagement and rebellion during adolescence. Our findings suggest that academic achievement and family connection may not be competing pursuits among adolescents. Instead, both are shaped by the general narratives about adolescence, and both are nurtured through the same lens of fulfilling growing responsibility.

SRCD: Can you please expand upon how this research might be helpful for parents, caregivers, teachers, school administrators, program providers, and others? 

Author team: The key takeaway is to frame the teen years not as a period of inevitable “storm and stress,” but as a window of opportunity for growth and responsibility. In China, where fulfilling family obligations is a core cultural virtue, parents and teachers can actively leverage this. Instead of just focusing on academic pressure, which most Chinese parents do, parents can empower their teens with meaningful family duties and acknowledge their contributions. Teachers can connect academic effort to the broader cultural goal of being responsible member of the group, which can motivate students to delay gratification and persevere through challenges. These insights also have implications for the design of both school curricula and extracurricular activities. In China, middle and high school education is typically centered on discipline and achievement. Meanwhile, students’ out-of-school time is often filled with after-school tutoring. To better support adolescents’ holistic development, school administrators and youth program developers should integrate family and social responsibility into both the curriculum and extracurricular programs, while ensuring that these practices remain relevant and aligned with contemporary needs. For instance, out-of-school programs could engage youth in family responsibilities while avoiding outdated emphases such as the absolute authority of parents. Similarly, schools might incorporate family obligations into homework assignments while adjusting the overall course load to allow students the time and space to participate in extracurricular and out-of-school activities. Ultimately, placing a stronger emphasis on a responsibility-oriented vision of youth development could help foster resilience and strengthen family ties, which are foundational for adolescents’ well-being. Importantly, this approach does not impose something new but instead draws on cultural traditions that already value care, responsibility, and connection.

SRCD: Can you please address some of the research limitations? 

Author team: First, although our three-wave longitudinal design is a strength, the findings are correlational, which means we cannot make definitive causal claims. We observed meaningful association over time, but we cannot conclude that holding positive views of the teen years directly leads to better outcomes. Second, our model primarily examined a one-way influence from sense of responsibility to youth adjustment. It is entirely possible that the relationship is bidirectional, that is, doing well in school and maintaining strong family bonds may further enhance a teen’s sense of responsibility. Finally, while these findings highlight promising connections, they are drawn from a specific cultural context (Chinese middle school students). Thus, policy implications should be taken with caution when generalizing to youth from other cultural backgrounds. 

SRCD: What's next in this field of research?

Author team: This study opens up several exciting avenues for future research, which are directly informed by its limitations. A crucial next step is to conduct cross-cultural research. The emphasis on family obligations is shared by many Asian (e.g., Filipino and Korean) and Latinx (e.g., Mexican and Colombian) cultures. Meanwhile, there are also many individualistic cultures that do not emphasize family obligations to the same degree. Examining whether holding positive views of teens as responsible family members is beneficial in various cultures is highly needed. It would help us understand what aspects of these beliefs are universal and which are culturally specific. Additionally, to move closer to establishing causality, more intervention studies are needed. For example, it is important to design intervention programs that address adolescents’ existing negative stereotypes about this life stage (e.g., the “storm and stress” view). Such programs should provide youth with clear explanations of where these stereotypes come from, why they persist, and why they are often inaccurate. By doing so, we can help adolescents reframe their perspectives and begin to view adolescence as a positive period of growth and contribution. Evidence from this line of research can inform practical strategies for schools and communities, leading to measurable improvements in adolescents’ academic engagement, social relationships, and overall well-being.

This research was funded by the National Natural Science Foundation of China, the Shuguang Program of Shanghai Municipal Education Commission and Shanghai Education Development Foundation to Bin-Bin Chen and the Center for Culture, Brain, Biology and Learning at Northwestern University to Yang Qu.

Summarized from an article in Child Development, “Viewing Teens as Responsible in Family: Implications for Chinese Youth’s Academic and Social Adjustment,” by Yang, B. (Northwestern University), Zhou, Z. (The University of Texas at Austin), Devakonda, V. (Northwestern University), Chen, B.B. (Fudan University), Qu, Y. (Northwestern University). Copyright 2025 The Society for Research in Child Development. All rights reserved.

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Journal

Child Development

DOI

10.1111/cdev.70013 

Method of Research

Survey

Subject of Research

People

Article Title

Viewing Teens as Responsible in Family: Implications for Chinese Youth’s Academic and Social Adjustment

Article Publication Date

2-Oct-2025

 

From lab to kitchen: How curdlan reshapes pineapple jam

Zhejiang University

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Turning pineapples into jam may soon become faster, cheaper, and more sustainable thanks to curdlan, a natural polysaccharide with unique gelling properties. Researchers tested varying levels of curdlan in pineapple jam and found that it cut cooking time from three hours to just one, while also strengthening texture, reducing water loss, and improving stability. Even with these changes, consumer panels reported no loss in taste or overall appeal. The study points to curdlan as a functional alternative to costly pectin, especially for low-pectin fruits like pineapple. These findings could help reduce food waste while keeping jams delicious and affordable.

Pineapple, the world's third most-produced tropical fruit, is rich in flavor and nutrition but highly perishable, with nearly one-third of harvests lost after picking. Processing pineapples into jam offers a way to preserve this fruit, yet traditional production relies heavily on pectin. Pectin is not only expensive and limited in supply but also naturally scarce in pineapple flesh, making jam production technically challenging. Manufacturers often struggle to balance consistency, stability, and cost. Due to these problems, there is a need to explore alternative gelling agents for pineapple jam production.

A team from Universiti Sains Malaysia and Mountains of the Moon University has identified curdlan as a promising substitute for pectin in jam-making. Their study, published (DOI: 10.1093/fqsafe/fyaf033) on July 18, 2025, in Food Quality and Safety, tested pineapple jams prepared with up to 1.5% curdlan. The researchers examined cooking efficiency, texture, color, and consumer acceptance. Their findings show that curdlan not only improved physical and structural properties but also maintained sensory qualities, pointing to a cost-effective innovation for one of the world's most popular fruit preserves.

The researchers prepared four jam formulations containing 0%, 0.5%, 1%, and 1.5% curdlan. The results were striking: the highest curdlan concentration reduced cooking time from three hours to just one. This efficiency gain stemmed from curdlan's ability to bind water, accelerate soluble solids accumulation, and form dense gel networks. The jams also displayed reduced syneresis—liquid separation that can spoil consistency—and lower water activity, both of which are critical for safe storage. Color measurements showed improvements in brightness, redness, and yellowness, while texture tests revealed firmer, less sticky jams. Microscopic imaging confirmed that curdlan created compact, well-structured networks that reinforced product stability. Importantly, a panel of 45 untrained tasters reported no significant differences in flavor, color, or overall acceptability across the samples. Interestingly, jams with 0.5% curdlan received the highest scores for spreadability, highlighting a balance between firmness and consumer-friendly texture. Taken together, these findings suggest that curdlan not only offers a practical solution to pectin shortages but also enhances efficiency and product quality in pineapple jam production.

"Curdlan could be a game-changer for fruit jam production," said lead author Shin-Yong Yeoh. "By improving texture and stability while reducing cooking time, it provides a low-cost and versatile alternative to pectin. What's remarkable is that consumers didn't notice any negative changes in taste or overall enjoyment, even with different curdlan levels. This means food producers can adopt it without compromising quality. Our study provides early evidence, but further research into industrial scalability and shelf-life stability will be essential before curdlan can reach wider commercial use."

Beyond pineapple, curdlan could transform the way many fruit-based preserves are made. Its ability to shorten cooking time points to lower energy use and faster processing, while its strong gelling properties may help reduce post-harvest fruit waste by stabilizing perishable crops. For manufacturers, switching to curdlan could cut costs by replacing pectin, which remains expensive and limited in supply. For consumers, it means affordable jams with the same taste and appeal they expect. Looking ahead, validating curdlan in large-scale production and across diverse fruit types could make it a cornerstone of more sustainable, accessible, and innovative food systems.

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References

DOI

10.1093/fqsafe/fyaf033

Original Source URL

https://doi.org/10.1093/fqsafe/fyaf033

Funding information

This research was funded by the Ministry of Higher Education Malaysia (MOHE) through the Fundamental Research Grant Scheme (FRGS), Project Code: FRGS/1/2024/TK05/USM/01/4.

About Food Quality and Safety

Food Quality and Safety (FQS) is an open access, international, peer-reviewed journal providing a platform to highlight emerging and innovative science and technology in the agro-food field, publishing up-to-date research in the areas of food quality, food safety, food nutrition and human health. It is covered by SCI-E and the 2024 Impact Factor (IF)=4.4, 5-yr IF=4.8.

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Journal

Food Quality and Safety

DOI

10.1093/fqsafe/fyaf033 

Subject of Research

Not applicable

Article Title

The impact of curdlan on the physical, microstructure, and sensory properties of pineapple jam