The findings are published this week in Cell, one of the scientific journals of Cell Press. Alexandra Walls and David Veesler in the Department of Biochemistry at the University of Washington in Seattle led the project.

Characteristics of the Delta and Omicron coronavirus variants of concern include enhanced transmissibility and immune evasion even in non-immunologically naïve individuals, compared to the ancestral pandemic coronavirus.

These characteristics, and the waning of immunity from vaccines, have led to breakthrough infections in vaccinated individuals. For the most part, otherwise healthy people who are vaccinated against the SARS-CoV-2 usually do not have severe symptoms if they do end up contracting the virus.

The researchers wanted to understand what effect catching the virus after being vaccinated has on neutralizing antibodies, and to see how durable and broad these responses are. Their hope is that advancing such knowledge will help guide vaccination policies and pandemic mitigation strategies.

Through their project the researchers learned that the degree of antibody response depended on whether a person has had one, two, three, or four exposures to the spike protein through infection, vaccination, or a mixture of the two. The scientists also checked antibody responses in groups of individuals who had been vaccinated after having COVID-19, those who were previously vaccinated and experienced a breakthrough infection, those who were vaccinated only, and those who were boosted and therefore vaccinated three times.

Among their study subjects, those who had completed a three-vaccination protocol, and those who had been vaccinated after recovering from COVID-19, and those with a breakthrough infection after vaccination launched almost comparable neutralizing antibody responses, in terms of magnitude and breadth. Their serum binding and antibody neutralizing responses to the spike protein in the current pandemic coronavirus variants were much more potent and lasting than those generated by people who had received only two doses of COVID-19 vaccine or who had a previous infection not followed by vaccination.

This observation suggested that the increased number of exposures to SARS-CoV-2 antigens, either through infection and vaccination or triple vaccination, enhanced the quality of antibody responses.

The researchers also looked at how broad the elicited antibodies could be. They investigated neutralization of the divergent Omicron SARS-CoV-2 variant of concern, currently responsible for the majority of cases in the United States. Their findings showed that boosted individuals (or those that have a mixture of infection and double vaccination) have neutralizing antibodies at similar levels to subjects vaccinated twice against the original ancestral strain. This suggests a large amount of immune evasion, but that vaccine boosters can help close the neutralizing antibody gap caused by Omicron.

Looking outside of the SARS-CoV-2 family shows a similar pattern, where repeated and multiple exposures improves the otherwise weak neutralizing antibody response to SARS-CoV. Finally, the authors did not identify improvements in antibody binding to common cold causing coronavirus spike proteins like OC43 or HKU1. This suggests that repeated SARS-CoV-2 exposure does not improve spike reactivity to more divergent coronaviruses. These findings support the development of broader sarbecovirus or coronavirus vaccines to be prepared in the event of a future spillover event.

The study groups consisted of about 15 people, from the Hospitalized or Ambulatory Adults with Respiratory Viral Infections, or HAARVI, project at the UW in Seattle. HAARVI, led by UW Medicine infectious disease physician Helen Chu, looks at recovered COVID-19 patients to study immune responses over time, to understand the long-term consequences of the infection, and to compare immune responses from vaccines and natural infections.

Researchers from the Department of Medicine and the Department of Laboratory Medicine and Pathology at the UW School of Medicine, and from Humabs Biomed SA, a subsidiary of Vir Biotechnology, also helped conduct the study.

The findings help explain how the new variant can escape pre-existing antibodies present in the human body, either from vaccination or naturally from a recent COVID-19 infection.

“We know that viruses evolve over time and acquire mutations, so when we first heard of the new Omicron variant, we wanted to identify the mutations specific to this variant,” said Kamlendra Singh, a professor in the MU College of Veterinary Medicine, assistant director of the MU Molecular Interactions Core and Bond Life Sciences Center investigator.

Singh collaborated with Saathvik Kannan, a freshman at Hickman High School in Columbia, Missouri, and Austin Spratt, an undergraduate student at MU, and Sid Byrareddy of the University of Nebraska Medical Center, to analyze protein sequences of Omicron samples from around the world, including South Africa, Botswana and the United States. The team identified 46 highly prevalent mutations specific to Omicron, including several located in the region of the virus’ spike protein where antibodies bind to the virus in order to prevent infection.

“The purpose of antibodies is to recognize the virus and stop the binding, which prevents infection,” Singh said. “However, we found many of the mutations in the Omicron variant are located right where the antibodies are supposed to bind, so we are showing how the virus continues to evolve in a way that it can potentially escape or evade the existing antibodies, and therefore continue to infect so many people.”

As antiviral treatments for individuals infected with COVID-19 continue to be developed, Singh explained that having a better understanding of how the virus is evolving will help ensure future antiviral treatments will be targeted toward the specific parts of the virus to produce the most effective outcomes.

In a recent trip to his native India, Singh met with Manish Sisodia, the deputy chief minister of Delhi, to discuss the launch of CoroQuil-Zn, a supplement that can be taken while infected with COVID-19 to help reduce one’s viral load. The supplement, which Singh helped to develop, is now being used by patients in Tamil Nadu, a state in India. The manufacturer will soon seek FDA approval for its distribution in the United States.

“The first step toward solving a problem is getting a better understanding of the specific problem in the first place,” Singh said. “It feels good to be contributing to research that is helping out with the pandemic situation, which has obviously been affecting people all over the world.”

“Omicron SARS-CoV-2 variant: Unique features and their impact on pre-existing antibodies” was recently published in Journal of Autoimmunity. Funding for the study was provided by the Bond Life Sciences Center, the National Institute of Allergy and Infectious Diseases and the National Strategic Research Institute at the University of Nebraska. Siddappa Byrareddy of the University of Nebraska Medical Center, Hitendra Chand of Florida International University and Kalicharan Sharma of Delhi Pharmaceutical Sciences and Research University were co-authors on the study.

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The researchers investigated how water flows in the Nicola watershed affect early summer-run Chinook salmon. The team used an advanced time-series model to understand 22 years of variation in Chinook salmon productivity. After accounting for ocean survival and density dependence, they discovered that the flow during August, when Chinook are rearing as juveniles, was the most important predictor of productivity. Higher August flows during adult spawning and migration also likely boost productivity, while lower flows during this time are linked to decline.

The results could help to inform water management given watershed activities and climate change in the region. The findings are newly published in the journal Ecological Solutions and Evidence.

“We found that August flows during juvenile rearing had the greatest impact on Chinook productivity out of any factor; the effect was very large,” says the study’s lead author, Luke Warkentin, who carried out the project as part of his masters research in SFU’s Salmon Watersheds Lab, in collaboration with scientists from Fisheries and Oceans Canada. “If there isn’t enough water during the summer, Chinook populations tend to decline.” On average, cohorts that experienced 50 per cent below average flows in the August of spawning and rearing had 29 per cent lower productivity.

Changing flows and cumulative effects

Over the past 100 years, Nicola River flows in August have decreased by 26 per cent, on average, based on analyses of long-term flow data.

“These long-term changes are probably the cumulative effect of climate change, water withdrawals for agricultural and other uses, and land use such as forestry,” says SFU biological sciences professor Jonathan Moore, the paper’s co-author.

Managing flows for people and fish

Water flows in rivers are controlled by many different human activities, such as water withdrawals for agriculture, dam operations, and forestry, as well as climate variability. The seasonal patterns of water flow can impact the survival and productivity of fishes. Yet, it can be difficult to know how much water particular rivers need in order to sustain or recover fish and their fisheries. The findings from this study can help guide management of environmental flows in systems with multiple demands on water systems, such as the Nicola River, and elsewhere.

In 2021, this region of B.C. suffered catastrophic floods and a heat dome that broke records and caused substantial harm to people and property.

“This data is helping to inform ongoing watershed planning and on-the-ground action in the Nicola by the five Nicola Bands and the Province,” says Leona Antoine who helps lead the Nicola Watershed Governance Project, and is associated with the Scw’exmx Tribal Council, not involved in the study. “Science such as this, as well as traditional knowledge and other sources of expertise, are guiding real change on the ground to steward this watershed.”

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“A large amount of heat from the energy we consume is essentially being thrown away, often dispersed right into the atmosphere,” said Shashank Priya, associate vice president for research and professor of materials science and engineering at Penn State. “We haven’t had cost-effective ways with conformal shapes to trap and convert that heat to useable energy. This research opens that door.”

Penn State researchers have been working to improve the performance of thermoelectric generators — devices that can convert differences in temperature to electricity. When the devices are placed near a heat source, electrons moving from the hot side to the cold side produce an electric current, the scientists said.

In prior work, the team created rigid devices that were more efficient than commercial units in high-temperature applications. Now the team has developed a new manufacturing process to produce flexible devices that offer higher power output and efficiency, the scientists said.

“These results provide a promising pathway toward widespread utilization of thermoelectric technology into waste heat recovery application,” said Wenjie Li, assistant research professor at Penn State. “This could have a significant impact on the development of practical thermal to electrical generators.”

Flexible devices better fit the most attractive waste heat sources, like pipes in industrial and residential buildings and on vehicles, the scientists said. And they don’t have to be glued on surfaces like traditional, rigid devices, which further decreases efficiency.

In tests being conducted on a gas flue, the new device exhibited 150% higher power density than other state-of-the-art units, the scientists reported in Applied Materials & Interfaces. A scaled-up version, just over 3-inches squared, maintained a 115% power density advantage. That version exhibited a total power output of 56.6 watts when placed on the hot surface, the scientists said.

“Think about an industrial power plant with pipes hundreds of feet long,” Priya said. “If you can wrap these devices around an area that large, you could generate kilowatts of energy from wasted heat that’s normally just being thrown away. You could convert discarded heat into something useful.”

Thermoelectric devices are made up of small couples, each resembling a table with two legs. Many of these two-leg couples are connected together, typically forming a flat, square device.

In creating the new device, scientists placed six couples along a thin strip. They then used flexible metal foil to connect 12 of the strips together, creating a device with 72 couples. Liquid metal was used between the layers of each strip to improve device performance, the scientist said.

“As you scale up these devices, you often lose power density, making it challenging to fabricate large-scale thermoelectric generators,” said Bed Poudel, associate research professor at Penn State. “This illustrates the extraordinary performance of our 72-couple device.”

The 72-couple device exhibited the highest reported output power and device power density from a single thermoelectric generator, the scientists said.

The gaps between the strips provide the flexibility to fit around shapes like pipes. The gaps also allow for flexibility in altering the fill factor, or the ratio between the area of thermoelectric material and the area of the device, which can be used to optimize thermoelectric devices for different heat sources, the scientists said.

Other Penn State researchers on the project were Amin Nozariasbmarz, assistant research professor; Han Byul Kang and Hangtain Zhu, postdoctoral researchers; and Carter Dettor, a former graduate student.

Ravi Anant Kishore, research engineer at National Renewable Energy Laboratory, also contributed.

Various authors contributing to this study were supported through Department of Energy, Office of Naval Research, Army Research Office, National Science Foundation and Defense Advanced Research Projects Agency.

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Water can exist in three phases: a frozen solid, a liquid, and a gas. When heat is applied to a frozen solid, it becomes a liquid. When applied to the liquid, it becomes vapor. This elementary principle is familiar to anyone who has observed a glass of iced tea on a hot day, or boiled a pot of water to make spaghetti.

When the heat source is hot enough, the water’s behavior changes dramatically. According to Boreyko, a water droplet deposited onto an aluminum plate heated to 150 degrees Celsius (302 degrees Fahrenheit) or above will no longer boil. Instead, the vapor that forms when the droplet approaches the surface will become trapped beneath the droplet, creating a cushion that prevents the liquid from making direct contact with the surface. The trapped vapor causes the liquid to levitate, sliding around the heated surface like an air hockey puck. This phenomenon is known as the Leidenfrost effect, named for the German doctor and theologian who first described it in a 1751 publication.

This commonly accepted scientific principle applies to water as a liquid, floating on a bed of vapor. Boreyko’s team found themselves wondering: Could ice perform in the same way?

“There are so many papers out there about levitating liquid, we wanted to ask the question about levitating ice,” said Boreyko. “It started as a curiosity project. What drove our research was the question of whether or not it was possible to have a three-phase Leidenfrost effect with solid, liquid, and vapor.”

Going into the ice

Curiosity sparked the first investigation in Boreyko’s lab some five years ago in the form of a research project by then-undergraduate student Daniel Cusumano. What he observed was fascinating. Even when the aluminum was heated above 150 C, the ice did not levitate on vapor as liquid does. Cusumano continued raising the temperature, observing the behavior of the ice as the heat increased. What he found was that the threshold for levitation was dramatically higher: 550 C (1022 F) rather than 150 C. Up until that threshold, the meltwater beneath the ice continued to boil in direct contact with the surface, rather than exhibit the Leidenfrost effect.

What was going on underneath the ice that prolonged the boiling? The project was picked back up by graduate student Mojtaba Edalatpour a short time later, to solve the mystery. Edalatpour had been working with Boreyko to develop novel methods of heat transfer and put that knowledge to work in approaching this problem. The answer turned out to be the temperature differential in the meltwater layer beneath the ice. The meltwater layer has two different extremes: Its bottom is boiling, which fixes the temperature at about 100 C, but its top is adhered to the remaining ice, which fixes it at about 0 C. Edalatpour’s model revealed that the maintenance of this extreme temperature differential consumes most of the surface’s heat, explaining why levitation was more difficult for ice.

Boreyko elaborated. “The temperature differential the ice is uniquely creating across the water layer has changed what happens in the water itself, because now most of the heat from the hot plate has to go across the water to maintain that extreme differential. So only a tiny fraction of the energy can be used to produce vapor anymore.”

The elevated temperature of 550 degrees Celsius for the icy Leidenfrost effect is practically important. Boiling water is optimally transporting heat away from the substrate, which is why you feel ample heat rising from a pot of water that is boiling, but not from a pot of water that is merely hot. This means that the difficulty in levitating ice is actually a good thing, as the larger temperature window for boiling will result in better heat transfer compared to using a liquid alone.

“It is much harder to levitate the ice than it was to levitate the water droplet,” said Boreyko. “Heat transfer plummets as soon as levitation begins, because when liquid levitates, it doesn’t boil anymore. It’s floating over the surface rather than touching, and touching is what causes it to boil the heat away. So, for heat transfer, levitation is terrible. Boiling is incredible.”

Using ice for heat transfer

As the team explored possibilities for practical application, they looked to their existing work. Since Edalatpour had extensive research in heat transfer, that topic became a logical fit.

Heat transfer comes most into play for cooling off things like computer servers or car engines. It requires a substance or mechanism that can move energy away from a hot surface, redistributing heat quickly to reduce the wear and tear on metal parts. In nuclear power plants, the application of ice to induce rapid cooling could become an easily-deployed emergency measure if power fails, or a regular practice for servicing power plant parts.

There are also potential applications for metallurgy. To produce alloys, it is necessary to quench the heat from metals that have been shaped in a narrow window of time, making the metal stronger and less brittle. If ice were applied, it would allow heat to be offloaded rapidly through the three water phases, quickly cooling the metal.

Boreyko also foresees a potential for applications in firefighting.

“You could imagine having a specially made hose that is spraying ice chips as opposed to a jet of water,” he said. “This is not science fiction. I visited an aerospace company that has an icing tunnel and they already have this technology where a nozzle sprays out ice particles as opposed to water droplets.”

With myriad possibilities, Boreyko and Edalatpour are excited about the new contribution that has come to the science world. Looking back over the past five years, they still credit this exciting development to their shared spark of curiosity and the drive to be creative in research.

Unlike a conventional camera, the light-field camera contains micro-lens arrays in front of the image sensor, which makes the camera small enough to fit into a smart phone, while allowing it to acquire the spatial and directional information of the light with a single shot. The technique has received attention as it can reconstruct images in a variety of ways including multi-views, refocusing, and 3D image acquisition, giving rise to many potential applications.

However, the optical crosstalk between shadows caused by external light sources in the environment and the micro-lens has limited existing light-field cameras from being able to provide accurate image contrast and 3D reconstruction.

The joint research team applied a vertical-cavity surface-emitting laser (VCSEL) in the near-IR range to stabilize the accuracy of 3D image reconstruction that previously depended on environmental light. When an external light source is shone on a face at 0-, 30-, and 60-degree angles, the light field camera reduces 54% of image reconstruction errors. Additionally, by inserting a light-absorbing layer for visible and near-IR wavelengths between the micro-lens arrays, the team could minimize optical crosstalk while increasing the image contrast by 2.1 times.

Through this technique, the team could overcome the limitations of existing light-field cameras and was able to develop their NIR-based light-field camera (NIR-LFC), optimized for the 3D image reconstruction of facial expressions. Using the NIR-LFC, the team acquired high-quality 3D reconstruction images of facial expressions expressing various emotions regardless of the lighting conditions of the surrounding environment.

The facial expressions in the acquired 3D images were distinguished through machine learning with an average of 85% accuracy — a statistically significant figure compared to when 2D images were used. Furthermore, by calculating the interdependency of distance information that varies with facial expression in 3D images, the team could identify the information a light-field camera utilizes to distinguish human expressions.

Professor Ki-Hun Jeong said, “The sub-miniature light-field camera developed by the research team has the potential to become the new platform to quantitatively analyze the facial expressions and emotions of humans.” To highlight the significance of this research, he added, “It could be applied in various fields including mobile healthcare, field diagnosis, social cognition, and human-machine interactions.”

This research was published in Advanced Intelligent Systems online on December 16, under the title, “Machine-Learned Light-field Camera that Reads Facial Expression from High-Contrast and Illumination Invariant 3D Facial Images.” This research was funded by the Ministry of Science and ICT and the Ministry of Trade, Industry and Energy.

The study, published in Earth and Planetary Science Letters, analysed the formation of more than 500 large Martian craters using a crater detection algorithm previously developed at Curtin, which automatically counts the visible impact craters from a high-resolution image.

Despite previous studies suggesting spikes in the frequency of asteroid collisions, lead researcher Dr Anthony Lagain, from Curtin’s School of Earth and Planetary Sciences, said his research had found they did not vary much at all for many millions of years.

Dr Lagain said counting impact craters on a planetary surface was the only way to accurately date geological events, such as canyons, rivers and volcanoes, and to predict when, and how big, future collisions would be.

“On Earth, the erosion of plate tectonics erases the history of our planet. Studying planetary bodies of our Solar System that still conserve their early geological history, such as Mars, helps us to understand the evolution of our planet,” Dr Lagain said.

“The crater detection algorithm provides us with a thorough understanding of the formation of impact craters including their size and quantity, and the timing and frequency of the asteroid collisions that made them.”

Past studies had suggested that there was a spike in the timing and frequency of asteroid collisions due to the production of debris, Dr Lagain said.

“When big bodies smash into each other, they break into pieces or debris, which is thought to have an effect on the creation of impact craters,” Dr Lagain said.

“Our study shows it is unlikely that debris resulted in any changes to the formation of impact craters on planetary surfaces.”

Co-author and leader of the team that created the algorithm, Professor Gretchen Benedix, said the algorithm could also be adapted to work on other planetary surfaces, including the Moon.

“The formation of thousands of lunar craters can now be dated automatically, and their formation frequency analysed at a higher resolution to investigate their evolution,” Professor Benedix said.

“This will provide us with valuable information that could have future practical applications in nature preservation and agriculture, such as the detection of bushfires and classifying land use.”

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