Nuclear waste to be scanned before final disposal

The final disposal operations of spent nuclear fuel are being prepared to start next year in Finland as the first place in the world.

UNIVERSITY OF HELSINKI

 

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THE CROSS-SECTION IMAGE OF A FUEL ROD ASSEMBLY SHOWS INDIVIDUAL RODS, LIKE A HANDFUL OF PENCILS SEEN FROM ABOVE.

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CREDIT: RIINA VIRTA

At Olkiluoto in Eurajoki, preparations are underway to start the disposal of spent nuclear fuel in the Finnish bedrock next year – as the first place in the world.

After use, nuclear fuel becomes strongly radiating and dangerous waste. It contains a large amount of uranium and plutonium, which are building blocks for nuclear weapons. All these materials must be intact when the fuel rods are stored in their final deposit. This is why they must be meticulously and dependably measured before depositing them.

“This way, we can be sure of what is being deposited in the bedrock, and that all nuclear materials will remain in peaceful use,” says visiting researcher Riina Virta at the University of Helsinki.

All the important information must be gathered before the final disposal. The measurements must also be stored in a way that will be accessible and understandable to human beings for thousands, even hundreds and thousands of years.

For her doctoral thesis, Riina Virta has studied measuring methods for nuclear waste at the University of Helsinki in cooperation with the Helsinki Institute of Physics (HIP). Virta also works as an inspector in the nuclear materials safeguards section of the Radiation and Nuclear Safety Authority.

Gamma camera sees inside assembly

In her thesis work, Riina Virta developed a PGET device, i.e. an imaging method called passive gamma emission tomography, which measures the gamma radiation emitted by spent nuclear fuel. Nuclear fuel consists of rods, a few metres long and containing uranium, which are gathered into an assembly to act as a fuel element. The PGET instrument can produce an exact cross-section image of the fuel assembly.

The cross-section image allows us to check that the assembly still retains all the rods. The challenging thing with this method is that the fuel dampens the radiation very efficiently.

“In practice, the radiation from the middle of the assembly just barely reaches the detector, i.e. the ‘camera’. We wanted to fix this problem in our research.”

The image quality was improved e.g. by developing the collection of data and using that data more wisely. The method was also developed so that the instrument can be used, not just in water, but in air, as well. This makes it adaptable to the Finnish plants taking care of the final disposal. The research also developed software tools to make the operative application of the method easier.

The performance of the method was proven with the help of an extensive library of field measurements carried out in Finnish nuclear power plants.

“This means the method has been studied in detail and found to work well, and now we are just waiting for the operations of final disposal to start in Olkiluoto,” says Virta.

M.Sc.(Tech.) Riina Virta will defend her doctoral dissertation “Gamma tomography of spent nuclear fuel for geological repository safeguards” on 4 June 2024 at 12 noon at the Faculty of Science at the University of Helsinki. The public examination will be held at Physicum E204, Gustaf Hällströmin katu 2. More details on the dissertation.

More information

 

Riina Virta

riina.virta@stuk.fi

+358 50 4713 550

Final information of disposed spent nuclear fuel with Finnish methods

 

Traditional characteristics of Meiyu-Baiu disappeared due to global warming

SCIENCE CHINA PRESS

 

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FIGURE 1. CONCEPTUAL FRAMEWORK OF HOW THE TRADITIONAL MEIYU HAS SHAPED THE UNIQUE ORIENT FOR MORE THAN A THOUSAND YEARS. THE MOST IMPORTANT SOCIOECONOMIC ASPECTS IN THE YANGTZE RIVER BASIN ARE AGROECOSYSTEM, CULTURE, AND ARCHITECTURE. THE ARROWS INDICATE THE CONNECTIONS BETWEEN THE DIFFERENT ASPECTS, AND THE ROUNDED ARROWS INDICATE INCREASES IN PARAMETERS.

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CREDIT: ©SCIENCE CHINA PRESS

During early summer, a unique and far-reaching meteorological phenomenon occurs in China’s Yangtze River Basin and the main islands of Japan, known as Meiyu in China and Baiu in Japan. Traditional Meiyu-Baiu with significantly misty features has a long course in Asian history and has shaped the unique Orient civilization over thousands of years (Figure 1).

Although the traditional Meiyu-Baiu is closely linked to moldy damage, its continuous and gentle rain moistens the paddy rice at the jointing and booting stage. Meanwhile, the warm and moist conditions also promote the growth of organisms and algae in lakes and rivers, which provide an abundance of food to fisheries. Hence, the Meiyu region is often called “the land of fish and rice” (Figure 1). In addition, rain like thin smoke and fog has shaped the behavioral traits of local inhabitants to be more sensitive, implicit, and elegant. The beauty of the traditional Meiyu became a frequently used literary image. Numerous oriental poems, ink-and-wash paintings, and historical documents have consistently expressed feelings about “misty rains” (Figure 2), which can date back to at least the Jin Dynasty (265–420 AD).

However, in recent decades, both the Meiyu and Baiu have seldom exhibited their traditional misty features. But owing to the lack of quantitative metrics applicable to misty rains, there is still no consensus on whether the traditional Meiyu-Baiu has been declining significantly. Although there have been studies on the detection and attribution of extreme Meiyu events (rainstorms or heatwaves), traditional Meiyu is not an extreme event, and the existing conclusion cannot be directly transferred to its changes. There is no robust understanding of whether and to what extent the changes in the traditional Meiyu-Baiu can be attributed to global warming.

Professors Huijun Wang and Zhicong Yin et al constructed a three-dimensional deviation degree of misty rain (D2MR) for the first time, and found that the D2MR showed a significant upward trend both in Meiyu and Baiu region (Figure 3). This indicates that Meiyu-Baiu in East Asia has gradually lost its traditional characteristics of misty rain, especially in the Meiyu region.

82.5% (75.2-87.2%) and 81.1% (42.6-96.1%) of the D2MR trend in the Meiyu and Baiu regions, respectively, can be attributed to human activities, in which greenhouse gas forcing is the main factor, while the influence of aerosols is relatively insignificant. In a warmer future, the Meiyu-Baiu will continue to further away from its traditional characteristics and enter the "new normal".

The authors, from the Center for Climate System Prediction Research (CCSP), further state that: (1) Human activity is much more active than in ancient times. Whether the suspension of the traditional misty rain is enough to promote and how it will promote the change of human social civilization in East Asia is still worthy of further discussion. (2) The ecosystem, energy system, and transportation network in East Asia may suffer huge losses due to the inability to adapt to the rapid transformation of Meiyu-Baiu to its extreme state, which requires the integration of more disciplines and government departments to tackle and respond.

 

Figure 2. Ancient Chinese poetry with Meiyu as cultural image or theme, and Misty Rain in Suzhou Western Hill (西山雨观图 in Chinese) drawn by Zhou Shen in ~1487 AD of the Ming Dynasty, now is collected by The Palace Museum

Changes of Meiyu-Baiu features.

 

Figure 3. (a) 3D plots of three sub-indexes of deviation degree of misty rain (D2MR) in Nanjing during 1961–2023. The blue and green dots indicate years when D2MR was greater or less than ±0.2 standard deviations. The yellow rhombus indicates standard misty rain. Red, blue and black years represent hot–dry, heavy rain and traditional Meiyu years, respectively. (b) Variation in D2MR (bars) averaged in the Meiyu and Baiu regions from 1961 to 2023 and their quadratic trends (black curves). The linear trend of D2MR at sites (scatter) is also shown, and the grey and black crosses indicate that the trend is higher than the 90% and 95% significance level.

CREDIT

©Science China Press

See the article:

Traditional Meiyu-Baiu has been suspended by global warming

https://doi.org/10.1093/nsr/nwae166

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JOURNAL

National Science Review

DOI

10.1093/nsr/nwae166 

 

Some species may better tolerate climate change than expected

UNIVERSITY OF LAUSANNE

 

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A NEW MODEL, DEVELOPED BY IFREMER AND LAUSANNE UNIVERSITY RESEARCHERS AND published in the journal Nature Ecology and Evolution, REASSESSES THE PROPORTION OF TERRESTRIAL AND MARINE SPECIES THREATENED WITH EXTINCTION BY CLIMATE CHANGE.

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CREDIT: OLIVIER DUGORNAY © CC-BY IFREMER

A new model, developed by Ifremer and Lausanne University researchers and published in the journal Nature Ecology and Evolution, reassesses the proportion of terrestrial and marine species threatened with extinction by climate change. While the forecasts of traditional models estimate that the diversity of terrestrial species in tropical areas could decrease by 54% between now and 2041-2060, this model is more moderate, predicting a decrease of 39%. Nevertheless, this proportion remains alarming and confirms the importance of taking urgent measures to mitigate climate change and its impact on biodiversity. 

Today, temperatures on Earth vary from around -70°C in Antarctica to +48°C at the equator. These "climatic limits" that currently exist on our planet have always evolved. For example, 130,000 years ago, during the last interglacial period, the climate was warmer and similar to what we could expect by the end of the century. The species that evolved during this period could therefore be "pre-adapted" to the changes to come. However, until now, statistical models predicting the response of species to climate change did not take this potential pre-adaptation into account, which could lead to inaccurate predictions.

Take the example of a tropical marine or terrestrial species: traditional statistical models predict that it will disappear in places where the temperature exceeds the current warm limit of 48°C. But this view could be too restrictive, as our knowledge is limited by the study of current climatic conditions. Could this species live with an air temperature of 50°C? Or in warmer or saltier water? Under the effect of climate change, such conditions could reappear and lead to an expansion of the climatic niche of certain species", explains Mathieu Chevalier, marine ecology researcher at Ifremer.

When a species is 'marked' by climatic conditions, it retains a pre-adaptation to these conditions that can last for thousands or even millions of years. If its habitat evolves towards a climate that the species has already experienced in the past, this pre-adaptation will provide it with a tolerance to these new climatic conditions", adds Antoine Guisan, professor of spatial ecology at the University of Lausanne.

The scientists from Ifremer and the University of Lausanne have applied their model to almost 25,000 terrestrial and marine species - including animals and plants - from around the world for which the International Union for Conservation of Nature (IUCN) provides geographical distribution maps. By cross-referencing this data in their model with scenarios of future climate change (IPCC/CMIP5), they found that 49% of these species currently live in climate niches that are contiguous ("stuck") to the limits of current climate conditions, and that 86% of them could have a niche potentially extending beyond current climate limits. This figure rises to 92% for marine species.

The most striking result concerns tropical areas, for terrestrial and marine species. It is widely accepted that climate change will lead to a massive loss of biodiversity in these areas, up to 54% of tropical terrestrial species by 2041-2060 according to traditional models. Our model puts this prognosis into perspective and predicts a reduction of 'only' 39% in species diversity," says Mathieu Chevalier, a marine ecology researcher at Ifremer.

Does that mean this is good news? Clearly not. Scientists are advising us to remain prudent: this estimate of threatened biodiversity remains alarming, and climate is not the only variable to take into account for a realistic prediction of species extinction risk. We also need to consider other anthropogenic pressures, such as habitat loss, pollution, overexploitation or biological invasions. It is clear, for example, that even if certain species are pre-adapted to future conditions, they will not be able to survive if their habitat disappears. Ideally, all these aspects should be taken into account, but here the scientists have concentrated on the climatic aspects, for which knowledge on past and future conditions is available.

Our study shows that it is important to constantly refine our models, and develop new hypotheses about the possible response of certain species. If it is likely that tropical species could better tolerate climate change than previously thought, the old estimates remain valid for species in cold, alpine and polar regions, and to a large extent for species in temperate zones, because the climate that currently prevails in these areas will no longer exist by 2041. These species are already living at the limit of their climatic niche and will not be able to tolerate significantly warmer temperatures. That is a sure thing! warns Olivier Broennimann, a researcher in spatial ecology at the University of Lausanne.

Read the article:

Chevalier M. (Ifremer), Broennimann O. and Guisan A. (Université de Lausanne), « Climate change may reveal currently unavailable parts of species ecological niches », May 2024, Nature Ecology & Evolution: https://doi.org/10.1038/s41559-024-02426-4 https://www.nature.com/articles/s41559-024-02426-4

 

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JOURNAL

Nature Ecology & Evolution

DOI

10.1038/s41559-024-02426-4 

ARTICLE TITLE

Climate change may unleash parts of past species’ ecological niches

ARTICLE PUBLICATION DATE

29-May-2024

 

Controlling ion transport for a blue energy future

Researchers from Osaka University show the control of ion passage through a nanopore membrane by applying a voltage to a gate electrode, paving the way for sustainable blue energy harvesting

OSAKA UNIVERSITY

 

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SCHEMATIC ILLUSTRATION DEPICTING GATE VOLTAGE CONTROL OF ION SELECTIVITY IN A NANOPORE.

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CREDIT: MAKUSU TSUTSUI

Osaka, Japan – Blue energy has the potential to provide a sustainable alternative to fossil fuels. In simple terms, it involves harnessing the energy produced when the ions in a salt solution move from high to low concentrations. A team including researchers from Osaka University has probed the effect of voltage on the passage of ions through a nanopore membrane to demonstrate greater control of the process.

In a study recently published in ACS Nano the researchers looked at tailoring the flow of ions through the array of nanopores that make up their membrane, and how this control could make applying the technology on a large scale a reality.

If the membranes are made from a charged material, nanopores can cause a current to flow through them by attracting solution ions with the opposite charge. The ions with the same charge can then move through the pore generating the current. This means that the pore material is very important and choosing it has been the means of controlling the flow and current to date.

However, producing the exact same pore structures in a range of different materials to understand their comparative performances is challenging. The researchers therefore decided to investigate another way of tailoring the flow of ions across nanopore membranes.

“Instead of simply using the basic surface charge of our membrane to dictate the flow, we looked at what happens when voltages are applied,” explains study lead author Makusu Tsutsui. “We used a gate electrode embedded across the membrane to control the field through voltage in a similar way to how semiconductor transistors work in conventional circuits.”

The researchers found that with no voltage applied there was no charge generated by the flow of cations—positively charged ions—because they were attracted to the negatively charged membrane surface.

However, if different voltages were applied, this performance could be tuned to allow cations to flow, even providing complete selectivity for cations. This led to a six-fold increase in the osmotic energy efficiency.

“By enhancing the charge density at the surface of the nanopores that make up the membrane, we achieved a power density of 15 W/m2,” says senior author Tomoji Kawai. “This is very encouraging in terms of progressing the technology.”

The study findings reveal the potential for scaling nanopore membranes for everyday application. It is hoped that nanopore osmotic power generators will provide a means of bringing blue energy to the mainstream for a more sustainable energy future.

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The study, “Gate-All-Around Nanopore Osmotic Power Generators,” was published in ACS Nano at https://doi.org/10.1021/acsnano.4c01989.

About Osaka University
Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world. Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.
Website: https://resou.osaka-u.ac.jp/en

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JOURNAL

ACS Nano

DOI

10.1021/acsnano.4c01989 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Gate-all-around nanopore osmotic power generators

ARTICLE PUBLICATION DATE

28-May-2024

 

Structural inequities amplify homelessness challenges for pregnant people in Washington DC

GEORGETOWN UNIVERSITY MEDICAL CENTER

WASHINGTON -- New research conducted with Washington, DC, residents who experienced homelessness during pregnancy sheds light on the intersection of homelessness, pregnancy, and racial inequities. The findings underscore the urgent need for policy and practice changes to support vulnerable populations.

The study, published May 30, 2024 in the journal Health Equity (DOI: 10.1089/heq.2023.0235), is grounded in a reproductive justice framework and delves into the lived experiences of 20 DC residents who faced homelessness while pregnant.

Homelessness during pregnancy is a symptom of broader structural inequities in access to safe and stable housing, and exacerbates adverse health outcomes for birthing people and infants. Conducted by researchers aiming for an action-oriented recommendations, the findings emphasized three key areas for policy and practice improvements:

• Timely Access to Safe Housing: One of the foremost recommendations is ensuring pregnant individuals have timely and meaningful access to safe and stable housing. The lack of secure housing not only impacts immediate health but also sets the stage for long-term challenges in child-rearing and family stability.
• Comprehensive Care Coordination: The study advocates for improved care coordination encompassing services and referrals that support physical, mental, and social well-being. Housing insecurity often intertwines with other complex needs, necessitating a holistic approach to healthcare and social support systems.
• Economic Justice and Affordable Housing: Access to a living wage and affordable housing emerged as critical components. Economic disparities, compounded by lack of affordable housing, disproportionately affect marginalized communities, amplifying the cycle of homelessness and health disparities.

The study’s lead researcher says stable housing is critical to health outcomes for the child and parents.

"Pregnant and parenting people in Washington, DC, must have a stable home as early in pregnancy as possible,” says Christina X. Marea, PhD, MA, MSN, FACNM, assistant professor of nursing at Georgetown’s School of Nursing. “That stability can improve health outcomes for birthing people and infants, support their ability to plan for the postpartum period, and enable them to enjoy this incredible life transition without the unrelenting stress and fear of homelessness.”

The study's insights have directly influenced strategic policy and practice recommendations, paving the way for a new model of collaboration across sectors. Initiatives like the DC Calling All Sectors Initiative (CASI), spearheaded by the DC Health Office of Health Equity, exemplify the commitment to bridging structural gaps and addressing the needs of vulnerable populations.

“The perspectives of people with lived experience has led directly to new initiatives at Community of Hope to support people who are pregnant and experiencing homelessness, says Kelly Sweeney McShane, CEO at Community of Hope, a community health center and homeless services provider who supported the study. “ The perinatal period is such an important one, and stable housing and access to healthcare are important components for both parent and baby during that critical period.”

The study's recommendations align with broader efforts to promote health equity and dismantle systemic injustices. Sustained political will and collaborative endeavors are essential to effectuating tangible improvements in housing accessibility and perinatal care.

The authors stress that as the nation grapples with ongoing challenges in housing insecurity and healthcare disparities, initiatives rooted in community based participatory research, that are intentionally informed by the lived experience of impacted residents, offer a beacon of hope for transformative change. The voices and experiences of those navigating homelessness during pregnancy serve as catalysts for a more inclusive and equitable future.

The work was supported by a grant from the Health Impact Project, a collaboration of the Robert Wood Johnson Foundation and the Pew Charitable Trusts.

C. Anneta Arno, PhD, MPH, Chief Health Equity Officer at DC Health, says, “The Office of Health Equity is appreciative of the grant, which enabled us to tangibly demonstrate the importance of proactive engagement of non-traditional partners, including impacted residents, government agencies, community-based organizations, as well as academia, to inform equity-driven collaborative practice change, by applying a health in all policies framework to address persistent structural barriers to health.”

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In addition to Marea, Arno, and McShane, collaborating researchers include Andrew Lozano, MPH, and Makeda Vanderpuije, MPH CPH,  DC Health Office of Health Equity; Kelley N. Robinson, PhD, CNM, CNE, University of Maryland; Karen Trister Grace, PhD, MSN, CNM, FACNM, George Mason University School of Nursing; and Noelene K. Jeffers, PhD, CNM, IBCLC, Johns Hopkins University School of Nursing.

The authors report having no personal financial interests related to the study.

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JOURNAL

Health Equity

DOI

10.1089/heq.2023.0235 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Navigating Homelessness Assistance While Pregnant: A Rapid Qualitative Research-to-Policy Collaboration in Washington DC

ARTICLE PUBLICATION DATE

30-May-2024

 

University of Maryland study shows N95 masks near-perfect at blocking escape of airborne COVID-19

Study finds all masks effective, but “duckbill” N95 masks far outperform others, suggests they should be the standard in high-risk settings

UNIVERSITY OF MARYLAND

COLLEGE PARK, Md. – In a head-to-head comparison of masks worn by people with active
COVID-19, the inexpensive “duckbill” N95 came out on top, stopping 98% of COVID-19 particles
in the breath of infected people from escaping into the air. Led by researchers from the University
of Maryland School of Public Health (SPH), results showed other masks also performed well,
blocking at least 70% of viral particles from escaping from the source – an infected person’s
exhaled breath.

The study, Relative efficacy of masks and respirators as source control for viral aerosol shedding
from people infected with SARS-CoV-2, published May 29 in eBioMedicine, a Lancet journal.

“The research shows that any mask is much better than no mask, and an N95 is significantly
better than the other options. That’s the number one message,” says the study’s senior author,
Dr. Donald Milton. Milton is a UMD SPH professor of environmental health and a global expert on
how viruses spread through the air.

The study started in May 2020, shortly after the pandemic began, and compared breath samples
from volunteers who had active COVID-19, testing the performance of four commonly-used
masks. Even without giving participants fit tests or training on how to wear masks correctly, all
masks significantly reduced the amount of virus escaping into the air. The study tested masks as
a way to control the spread of the virus from the source, i.e. the infected person, and did not test
masks as protection from COVID-19 in the surrounding air.

“Because COVID-19 is airborne, we focused on the extent to which wearing a mask reduces
contamination of the air around you,” Milton says. This latest study is a continuation of
investigations by UMD’s Public Health AeroBiology Lab (PHAB Lab) into how contagious
respiratory viruses such as influenza contaminate the air.

Researchers asked volunteers with COVID-19 to breathe into a unique contraption known as the
Gesundheit II Machine, developed by Milton and colleagues to measure viruses in exhaled
breath. Participants, who breathed into the machine for 30 minutes at a time, were asked to do a
variety of vocalizations such as repeating the alphabet, singing Happy Birthday, and even
honoring UMD’s mascot by repeatedly shouting “Go Terps!”

In each instance, researchers measured the amount of viral particles in the exhaled breath of
volunteers, pairing each 30-minute session of breathing with a mask on with another 30-minute
session with no mask.

“Data from our study suggests that a mildly symptomatic person with COVID-19 who is not
wearing a mask exhales a little over two infectious doses per hour,” says first author Dr. Jianyu
Lai, a postdoctoral researcher at the PHAB Lab. “But when wearing an N95 mask, the risk goes
down exponentially.”

The duckbill N95 blocked 99% of large particles and 98% of small particles from escaping out of
a person’s mask. Milton says the design’s tight seal, a powerful filter, and large air space for
breath to move around all contribute to the duckbill’s success.

Surprisingly, KN95 masks – the disposable masks used widely – were no more effective than
cloth or surgical masks. The study found that a common brand of KN95 masks leak more air than
duckbills or other studied masks, because they don’t conform to the face well. That flaw is
compounded by a powerful filter with more flow resistance that pushes air out of the mask at the
sides instead of through the filter, allowing more virus particles to escape into the surrounding air.

Cloth masks also outperformed both KN95 and surgical masks. Milton theorizes that cloth masks
with greater coverage, wrap around the face and give a better seal than either KN95 or surgical
masks. With cloth mask filters, flow resistance is also lower, allowing breath to pass through the
filter and not leak out the sides of the mask.

Limiting the amount of viral particles in the air is a key way to control highly contagious
respiratory viruses in general, Milton said. This is even more the case with the COVID-19 virus,
given transmissibility has increased over time, with Omicron in particular breaking through the
immunity people developed from vaccinations or prior infections.

“Our research shows definitively why it’s so important to have non-pharmaceutical responses like
wearing masks, and why we need studies like this to illuminate which masks are most effective,”
says Milton.

Both Milton and Lai hope that their findings will inform health policies going forward, including
when combatting potential outbreaks like bird flu or even the common flu.

“Duckbill N95 masks should be the standard of care in high-risk situations, such as nursing
homes and health care settings,” Lai says. “Now, when the next outbreak of a severe respiratory
virus occurs, we know exactly how to help control the spread, with this simple and inexpensive
solution.”

In addition to researchers from the UMD School of Public Health, collaborators include authors
from the UMD A. James Clark School of Engineering and the World Health Organization
Collaborating Centre for Infectious Disease Epidemiology and Control at the University of Hong
Kong, China.

This research was supported by the Prometheus-UMD, sponsored by the Defence Advanced
Research Projects Agency (agreement N66001-18-2-4015), the National Institute of Allergy and
Infectious Diseases Centers of Excellence for Influenza Research and Surveillance (contract
12-HHSN272201400008C), and the Centers for Disease Control and Prevention (contract
200-2020-09528); by a grant from the Bill & Melinda Gates Foundation; and by a gift from The
Flu Lab.

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JOURNAL

The Lancet

 

Innovative bird-eye-inspired camera developed for enhanced object detection

A new type of perovskite-based camera specializing in object detection is developed by mimicking bird's eye

INSTITUTE FOR BASIC SCIENCE

 

IMAGE: 

STRUCTURES AND FUNCTIONS OF BIRD’S EYE. (A) BIRD VISION. (B) DEEP CENTRAL FOVEA AND FOUR TYPES OF CONES. (C) FOVEATED VISION AND TETRACHROMATIC VISION.

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CREDIT: INSTITUTE FOR BASIC SCIENCE

The eyes of raptors such as eagles can accurately perceive prey from kilometers away. Is it possible to model the camera technology after the bird’s eyes?

Researchers developed a new type of camera, which was inspired by the structures and functions of bird's eyes. A research team led by Prof. KIM Dae-Hyeong at the Center for Nanoparticle Research within the Institute for Basic Science (IBS), in collaboration with Prof. SONG Young Min at the Gwangju Institute of Science and Technology (GIST), has developed perovskite-based camera specializing in object detection.

The eyes of different organisms in the natural world have evolved and been optimized to suit their habitat and the environment in which they survive. As a result of countless years of evolutionary adaptation to the environment of living and flying at high altitudes, bird eyes also have unique structures and visual functions (Figure 1a).

In the retina of an animal's eye, there is a small pit called the fovea that refracts the light entering the eye. Unlike the shallow foveae found in human eyes, bird eyes have deep central foveae, which refract the incoming light to a large extent. The region of the highest cone density lies within the foveae (Figure 1b), allowing the birds to clearly perceive distant objects through magnification (Figure 1c). This specialized vision is known as foveated vision.

While human eyes can only see visible light, bird eyes have four cones that respond to ultraviolet (UV) as well as visible (red, green, blue; RGB) light. This tetrachromatic vision enables birds to acquire abundant visual information and effectively detect target objects in a dynamic environment (Figure 1c).

Inspired by these capabilities, the IBS research team designed a new type of camera that specializes in object detection, incorporating artificial fovea and a multispectral image sensor that responds to both UV and RGB (Figure 2a). First, the researchers fabricated the artificial fovea by mimicking the deep central foveae in the bird's eyes (Figure 2b) and optimized the design through the optical simulation. This allows for the camera to magnify distant target objects without image distortion.

The team then used perovskite, a material known for its excellent electrical and optical properties, to fabricate the multispectral image sensor. Four types of photodetectors were fabricated using different perovskite materials that absorb different wavelengths. The multispectral image sensor was finally fabricated by vertically stacking the four photodetectors (Figures 2c and 2d).

The first co-author Dr. PARK Jinhong states, “We also developed a new transfer process to vertically stack the photodetectors. By using the perovskite patterning method developed in our previous research, we were able to fabricate the multispectral image sensor that can detect UV and RGB without additional color filters.”

Conventional cameras that use a zoom lens to magnify objects have the disadvantage of focusing only on the target object and not its surroundings. On the other hand, the bird-eye-inspired camera provides both a magnified view of the foveal region along with the surrounding view of the peripheral region (Figures 3a and 3b). By comparing the two fields of vision, the bird-eye-inspired camera can achieve greater motion detection capabilities than the conventional camera (Figure 3c and 3d). In addition, the camera is more cost-effective and lightweight as it can distinguish UV and RGB light without additional color filters.

The research team verified the object recognition and motion detection capabilities of the developed camera through simulations. In terms of object recognition, the new camera demonstrated a confidence score of 0.76, which is about twice as high as the existing camera system's confidence score of 0.39. The motion detection rate also increased by 3.6 times compared to the existing camera system, indicating significantly enhanced sensitivity to motion.

"Birds’ eyes have evolved to quickly and accurately detect distant objects while in flight. Our camera can be used in areas that need to detect objects clearly, such as robots and autonomous vehicles. In particular, the camera has great potential for application to drones operating in environments similar to those in which birds live,” remarked Prof. Kim.

This innovative camera technology represents a significant advancement in object detection, offering numerous potential applications across various industries.

Bird-eye-inspired camera. (a) Schematic view of bird-eye-inspired camera. (b) Artificial fovea. (c) Schematic of a multispectral image sensor. (d) Multispectral image sensor.

Performance of the bird-eye-inspired camera. (a) Setup for measurement. (b) Bird-eye-inspired camera perceives both the distant object (star) through magnification in the foveal region and nearby objects (triangle, square, circle) in the peripheral region. (c, d) The multispectral image sensor can distinguish UV and RGB light without color filters and capture colored images.

CREDIT

Institute for Basic Science

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JOURNAL

Science Robotics

DOI

10.1126/scirobotics.adk6903 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Avian-eye-inspired perovskite artificial vision system for foveated and multispectral imaging

ARTICLE PUBLICATION DATE

29-May-2024