Tech

ORLANDO, April 30, 2020 - A University of Central Florida researcher and his team have developed an advanced new rocket-propulsion system once thought to be impossible.

The system, known as a rotating detonation rocket engine, will allow upper stage rockets for space missions to become lighter, travel farther, and burn more cleanly.

The result were published this month in the journal Combustion and Flame.

"The study presents, for the first time, experimental evidence of a safe and functioning hydrogen and oxygen propellant detonation in a rotating detonation rocket engine," said Kareem Ahmed, an assistant professor in UCF's Department of Mechanical and Aerospace Engineering who led the research.

The rotating detonations are continuous, Mach 5 explosions that rotate around the inside of a rocket engine, and the explosions are sustained by feeding hydrogen and oxygen propellant into the system at just the right amounts.

This system improves rocket-engine efficiency so that more power is generated while using less fuel than traditional rocket energies, thus lightening the rocket's load and reducing its costs and emissions.

Mach 5 explosions create bursts of energy that travel 4,500 to 5,600 miles per hour, which is more than five times the speed of sound. They are contained within a durable engine body constructed of copper and brass.

The technology has been studied since the 1960s but had not been successful due to the chemical propellants used or the ways they were mixed.

Ahmed's group made it work by carefully balancing the rate of the propellants, hydrogen and oxygen, released into the engine.

"We have to tune the sizes of the jets releasing the propellants to enhance the mixing for a local hydrogen-oxygen mixture," Ahmed said. "So, when the rotating explosion comes by for this fresh mixture, it's still sustained. Because if you have your composition mixture slightly off, it will tend to deflagrate, or burn slowly instead of detonating."

Ahmed's team also had to capture evidence of their finding.
They did this by injecting a tracer in the hydrogen fuel flow and quantifying the detonation waves using a high-speed camera.

"You need the tracer to actually see that explosion that is happening inside and track its motion," he said. "Developing this method to characterize the detonation wave dynamics is another contribution of this article."

William Hargus, lead of the Air Force Research Laboratory's Rotating Detonation Rocket Engine Program, is a co-author of the study and began working with Ahmed on the project last summer.

"As an advanced propulsion spectroscopist, I recognized some of the unique challenges in the observation of hydrogen-detonation structures," Hargus said. "After consulting with Professor Ahmed, we were able to formulate a slightly modified experimental apparatus that significantly increased the relevant signal strength."

"These research results already are having repercussions across the international research community," Hargus said.
"Several projects are now re-examining hydrogen detonation combustion within rotating detonation rocket engines because of these results. I am very proud to be associated with this high-quality research."

Engineering researchers have created ultrathin, stretchable electronic material that is gas permeable, allowing the material to "breathe." The material was designed specifically for use in biomedical or wearable technologies, since the gas permeability allows sweat and volatile organic compounds to evaporate away from the skin, making it more comfortable for users - especially for long-term wear.

"The gas permeability is the big advance over earlier stretchable electronics," says Yong Zhu, co-corresponding author of a paper on the work and a professor of mechanical and aerospace engineering at North Carolina State University. "But the method we used for creating the material is also important because it's a simple process that would be easy to scale up."

Specifically, the researchers used a technique called the breath figure method to create a stretchable polymer film featuring an even distribution of holes. The film is coated by dipping it in a solution that contains silver nanowires. The researchers then heat-press the material to seal the nanowires in place.

"The resulting film shows an excellent combination of electric conductivity, optical transmittance and water-vapor permeability," Zhu says. "And because the silver nanowires are embedded just below the surface of the polymer, the material also exhibits excellent stability in the presence of sweat and after long-term wear."

"The end result is extremely thin - only a few micrometers thick," says Shanshan Yao, co-author of the paper and a former postdoctoral researcher at NC State who is now on faculty at Stony Brook University. "This allows for better contact with the skin, giving the electronics a better signal-to-noise ratio.

"And gas permeability of wearable electronics is important for more than just comfort," Yao says. "If a wearable device is not gas permeable, it can also cause skin irritation."

To demonstrate the material's potential for use in wearable electronics, the researchers developed and tested prototypes for two representative applications.

The first prototype consisted of skin-mountable, dry electrodes for use as electrophysiologic sensors. These have multiple potential applications, such as measuring electrocardiography (ECG) and electromyography (EMG) signals.

"These sensors were able to record signals with excellent quality, on par with commercially available electrodes," Zhu says.

The second prototype demonstrated textile-integrated touch sensing for human-machine interfaces. The authors used a wearable textile sleeve integrated with the porous electrodes to play computer games such as Tetris. Related video can be seen at https://youtu.be/7AO_cq8A_BE.

"If we want to develop wearable sensors or user interfaces that can be worn for a significant period of time, we need gas-permeable electronic materials," Zhu says. "So this is a significant step forward."

A new algorithm could enable faster, less expensive detection of weapons-grade nuclear materials at borders, quickly differentiating between benign and illicit radiation signatures in the same cargo.

The development is a collaboration among researchers at the University of Michigan, University of Illinois, Los Alamos National Laboratory, Heriot-Watt University (Edinburgh, Scotland) and University of Edinburgh.

"We hope that the findings will be helpful in reducing the false positive alarms at radiation portal monitors, even in scenarios with multiple sources present, and enable the use of cost-effective detectors, such as organic scintillators," said Angela DiFulvio, assistant professor of nuclear, plasma and radiological engineering at the University of Illinois and corresponding author of the study recently published in Scientific Reports.

DiFulvio is also a former postdoctoral researcher in the Detection for Nuclear Nonproliferation Group at U-M, led by Sara Pozzi, a professor of nuclear engineering and radiological science.

Nations need to protect their citizens from the threat of nuclear terrorism. Nuclear security deters and detects the smuggling of special nuclear materials--highly enriched uranium, weapons-grade plutonium or materials that produce a lot of radiation--across national borders.

The researchers developed an algorithm capable of identifying weak radiation signals, such as might be seen from plutonium encased materials that absorb radiation. It works even in the presence of a high radiation background, including everyday sources such as cosmic rays from space and radon from the rock underfoot.

Based on their results, they believe the use of their algorithm could improve the ability of radiation portal monitors at national borders to tell the difference between potential smuggling activity and benign radiation sources. For instance, naturally occurring radioactive materials such as ceramics and fertilizers, or radionuclides in recently treated nuclear medicine patients, can set off "nuisance" alarms at radiation scanning facilities.

"There's also the concern that somebody might want to mask a radioactive source, or special nuclear material, by using naturally occurring radioactive materials such as granite or kitty litter," said Pozzi, who is also senior author on the paper.

"As vehicles or boxes are scanned, the data from the detector can be put through these algorithms that unmix the different sources. The algorithms can quickly identify whether special nuclear materials are present."

Unmixing sources so that smuggling activity can't be hidden among benign radiation sources is hard to do quickly. For that, the team turned to specialists in machine learning, who could use data collected by Pozzi's group to "train" algorithms to look for the signatures of materials that could be used to make a nuclear bomb.

"We crafted an unmixing model that both reflects the basic physics of the problem and was also amenable to fast computation," said co-author Alfred Hero, the John H. Holland Distinguished University Professor of Electrical Engineering and Computer Science and R. Jamison and Betty Williams Professor of Engineering at U-M.

This research began at U-M as part of the Consortium for Verification Technology, a five-year $25 million nuclear nonproliferation research program funded by the U.S. Nuclear National Security Administration, led by Pozzi. DiFulvio continued the work when she moved to Illinois in 2018.

"This work is a powerful example of the benefit of close and sustained collaboration between computational data scientists and nuclear engineers, resulting in major improvement of nuclear radiation detection and identification," Hero said.

Alzheimer’s disease is the sixth leading cause of death in the United States, affecting one in 10 people over the age of 65. Scientists are engineering nanodevices to disrupt processes in the brain that lead to the disease.

People who are affected by Alzheimer’s disease have a specific type of plaque, made of self-assembled molecules called β-amyloid (Aβ) peptides, that build up in the brain over time. This buildup is thought to contribute to loss of neural connectivity and cell death. Researchers are studying ways to prevent the peptides from forming these dangerous plaques in order to halt development of Alzheimer’s disease in the brain.

In a multidisciplinary study, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, along with collaborators from the Korean Institute of Science and Technology (KIST) and the Korea Advanced Institute of Science and Technology (KAIST), have developed an approach to prevent plaque formation by engineering a nano-sized device that captures the dangerous peptides before they can self-assemble.

“We’ve taken building blocks from nanotechnology and biology to engineer a high-capacity ‘cage’ that traps the peptides and clears them from the brain.” — Elena Rozhkova, scientist, Center for Nanoscale Materials

The β-amyloid peptides arise from the breakdown of an amyloid precursor protein, a normal component of brain cells,” said Rosemarie Wilton, a molecular biologist in Argonne’s Biosciences division. “In a healthy brain, these discarded peptides are eliminated.”

In brains prone to the development of Alzheimer’s, however, the brain does not eliminate the peptides, leaving them to conglomerate into the destructive plaques. 

“The idea is that, eventually, a slurry of our nanodevices could collect the peptides as they fall away from the cells — before they get a chance to aggregate,” added Elena Rozhkova, a scientist at Argonne’s Center for Nanoscale Materials (CNM), a DOE Office of Science User Facility.

Decorating the surface

The researchers covered the surface of the new nanodevice with fragments of an antibody — a type of protein — that recognizes and binds to the Aβ peptides. The surface of the nanodevice is spherical and porous, and its craters maximize the available surface area for the antibodies to cover. More surface area means more capacity for capturing the sticky peptides.

To find the optimal coating, the scientists first searched previous literature to identify antibodies that have high affinity to Aβ peptides. It was important to choose an antibody that attracts the peptides but doesn’t bind to other molecules in the brain. Then the team, led by Wilton, produced the antibodies in bacteria and tested their performance.

A full antibody molecule can be up to a few dozen nanometers long, which is big in the realm of nanotechnology. However, only a fraction of this antibody is involved in attracting the peptides. To maximize the effectiveness and capacity of the nanodevices, Wilton’s group produced tiny fragments of the antibodies to decorate the nanodevice’s surface.

Engineering and testing the nanodevice

The scientists at CNM constructed the base of the porous, spherical nanodevices out of silica, a material that has long been used in biomedical applications due to its flexibility in synthesis and its nontoxicity in the body. Coated with the antibody fragments, the nanodevices capture and trap the Aβ peptides with high selectivity and strength. 

“Many attempts to prevent Alzheimer’s have focused on inhibiting enzymes from cutting β-amyloid peptides off of the cell’s surface,” said Rozhkova, who led the project at CNM. “Our elimination approach is more direct. We’ve taken building blocks from nanotechnology and biology to engineer a high-capacity ‘cage’ that traps the peptides and clears them from the brain.”

At CNM, the scientists tested the effectiveness of the devices by comparing how the peptides behaved in the absence and presence of the nanodevices. Using in vitro transmission electron microscopy (TEM), they observed a notable decline in peptide aggregation in the presence of the nanodevices. They further analyzed the interactions using confocal laser scanning microscopy and microscale thermophoresis measurement, two additional techniques for characterizing interactions at the nanoscale.

The scientists also performed small-angle X-ray scattering to study the processes that make the nanodevices porous during synthesis. The researchers performed the X-ray characterization, led by Byeongdu Lee, a group leader in Argonne’s X-ray Science division, at beamline 12-ID-B of the lab’s Advanced Photon Source (APS), a DOE Office of Science User Facility.

These studies supported the case that the nanodevices sequester the peptides from the pathway to aggregation by more than 90 percent compared to the control silica particles without the antibody fragments. However, the devices still needed to demonstrate their effectiveness and safety within cells and brains.

Joonseok Lee — who originally proposed this experiment at Argonne as a Director’s Postdoctoral Appointee and pioneered the design for the nanodevice — continued the study of the therapeutic potential of this device at KIST and KAIST.

“The Director’s Postdoctoral Position is a rare opportunity offered at Argonne that allows for unique research projects and cross-field collaborations that might not otherwise be possible,” said Rozhkova. “We have incredible minds at the lab who want to explore topics that don’t fall under a predefined area of research, and this program encourages this creativity and innovation.”

The in vivo experiments — experiments that took place in living cells — performed by Lee and his collaborators showed that the nanodevices are nontoxic to cells. They also tested the effectiveness of the devices in the brains of mice with Alzheimer’s, demonstrating around 30 percent suppression of plaque formation in brains containing the nanodevices compared to control brains.  The research on mice was conducted at KIST and KAIST in South Korea with appropriate government approvals.

This study combined the strengths of antibody engineering and nanotechnology, the power of two DOE User Facilities at Argonne and innovative collaboration resulting from the laboratory’s postdoctoral program to explore a technological approach to preventing Alzheimer’s.

Using a similar approach, scientists may also be able to pair the silica nanoparticles with different antibodies that target molecules related to other neurodegenerative diseases, such as Huntington’s disease and Parkinson’s disease, which also involve abnormal protein aggregation. The porous nanoparticles may be further upgraded for use in imaging applications including fluorescent imaging and magnetic resonance imaging.

Parents and carers should ensure that physical activity is part of the routine for children and families during the COVID-19 lockdown, according to an international study involving the University of Strathclyde.

The study, detailed in a comment article published in The Lancet Child & Adolescent Health, covers 15 nations. It found that time spent in places such as parks, beaches and community gardens reduced by nearly a third between the week ending 23 February - before the World Health Organization (WHO) declared a COVID-19 pandemic - and the week ending 5 April.

Travel by public transport was down by more than half - 59% - over the same period.

While these and other restrictions are in keeping with the global effort to halt the spread of COVID-19, the researchers found that they were having the effect of reducing still further what were often already low levels of physical activity in children.

The researchers make a number of recommendations to families, health professionals, teachers and policy-makers on promoting healthy activity, including:

taking the opportunity to go outdoors, while observing distancing regulations

incorporating physical activity into children's daily routines - supported by use of electronic media - and breaking up extended sedentary periods every 30 to 60 minutes; families should also be encouraged to join in while observing distancing regulations

keeping children's bedtime and rising time consistent, keeping screens out of the rooms where they sleep and avoiding screen use before bedtime

health professionals recommending current guidelines to parents, family members and caregivers

promotion by governments of healthy movement behaviours in children as part of response strategies and public messages

regular media messages promoting physical activity

Children advocating for their right to a healthy, active life within the COVID-19 restrictions.

Professor John Reilly, of Strathclyde's School of Psychological Sciences & Health, is the sole UK participant in the study.

He said: "The measures against COVID-19 are in place for a very good reason but this reduction in physical activity could be seen as an unintended consequence. Even before the lockdown measures, it was a major problem; our previous research has found that, in Scotland alone, fewer than 20% of children were meeting physical activity guidelines.

"It's important that people make whatever use of their environment they can and take the opportunities they can to keep physical activity going. The vast majority of children have access to outdoor spaces they can still use.

"While we have been fortunate with the weather during lockdown, even screen time can also incorporate activity resources, such as online fitness sessions. Breaks in screen time are also important but one reason physical activity is most needed just now is that school is the place where children most often have it.

"We have found that they are much less active on the non-school days of weekends and holidays; our concern is that they are missing out not only in education but also in activity."

The COVID-19 pandemic emerged at a time when climate and energy policies were experiencing greater attention and--in some cases--greater momentum. But the ensuing global health emergency and economic crisis mean that the circumstances under which these climate and energy policies were conceived have drastically changed. In a Commentary published April 29 in the journal Joule, energy and climate policy researchers in Switzerland and Germany provide a framework for responsibly and meaningfully integrating policies supporting the clean energy transition into the COVID-19 response in the weeks, months, and years to come.

"We're writing this commentary as COVID-19 fundamentally changes the economic environment of the clean energy transition, requiring policy makers to take major decisions within short timeframes," says senior author Tobias S. Schmidt of ETH Zurich. "While many blogs or comments put forward 'shopping' lists of which policies to enact or which technologies to support, much of the advice lacked structure."

In their Commentary, Schmidt and his colleagues argue against small "green wins" in the short-term that could prevent meaningful change in the long-term. "Bailouts should exclude sectors that are clearly incompatible with the Paris Agreement, such as tar sands development, but at the same time, bailout decisions primarily have to consider the societal value of uninterrupted service and of safeguarding jobs," Schmidt says. "Instead, policymakers should consider increasing their leverage to shape business activities for Paris Agreement-compatible pathways in the future, for instance, by taking equity stakes or securing a say in the future strategy of bailed-out corporations."

"The general public should understand that the short-term emissions reductions we are experiencing due to the lockdowns will not have major effects on climate change," Schmidt says. "To decarbonize our energy systems and industry, we need structural change, meaning more and not less investment."

Once the immediate crisis has passed, when many countries will have to address a major economic downturn, the authors say that low interest rates and massive public spending could offer important opportunities for the clean energy transition. "It is essential that we not repeat the mistakes of the post-financial crisis bailouts, which often led to massive increases in CO2 emissions," says Schmidt.

Going forward, he says, "We think the COVID-19 pandemic has reminded us that we require policies that are proof to exogenous shocks, and we hope that future research will support policy makers in developing shock-proof policy designs."

EUGENE, Ore. -- April 29, 2020 -- Conservation efforts for the African forest elephant have been hindered by how little is known the large animal, according to researchers.

A newly published study by a 10-member international research team, including University of Oregon biological anthropologist Nelson Ting, offers new information that could help to understand and protect the elephants amid increasing threats to their existence.

The team's study, published in PLOS ONE, suggests that the forest elephant population size is smaller than believed, leaving the species in an even graver position than previously acknowledged. This is based on one of the largest known populations, the researchers concluded, being 40 to 80 percent smaller than previously suggested.

The new findings provide insights into a revised population count and social behavior of the forest elephants, Loxodonta cyclotis. Both factors have been understudied, even as the elephant's population has dramatically declined over recent decades from human-related activities like habitat loss and poaching.

"Forest elephants are among the most threatened animals, but their biology and behavior remain poorly understood," said Ting, who is also a member of the UO's Institute of Ecology and Evolution. "More information is key to figuring out the best ways to protect them and prevent extinction."

Ting had a senior role in the study, which was led by UO graduate student Colin Brand and Gabonese scientist Mireille Johnson. It also featured several collaborators from the Smithsonian Institution.

Ting was drawn to studying the elephants' elusive nature in the same Central African jungles where he was studying primates, leading to a partnership with Johnson, who specializes in forest elephants.

African elephants often are grouped with the better-known savanna elephants, also known as bush elephants, Loxodonta africana, resulting in less scrutiny. The two tusked animals, however, are actually quite different, Ting said.

Reproductive lives, habitat preference, and physical characteristics such as body size, ear shape, and tusk shape and color are among the differences.

Savanna elephants roam open landscapes. Forest elephants stay in more densely wooded areas, where they are harder to study and count.

The research was done in the southern Industrial Corridor of the Gamba Complex of Protected Areas in southwestern Gabon, a global stronghold for forest elephants.

To assess population size, the researchers counted elephants using a method known as genetic capture-recapture - which involves systematically collecting dung piles and analyzing their genetic composition to match the DNA of each deposit to its owner. The approach is like collecting genetic fingerprints for the elephants, Ting said.

In previous methodology, Ting said, researchers also counted dung piles but could not differentiate those deposited by one individual from another. That method can lead to over-counting since the same elephant could be responsible for multiple mounds.

Previous methodology had assessed the elephant population size in the Gamba Complex Industrial Corridor to be approximately 10,000 individuals, which would be a substantial proportion of the global forest elephant population, the researchers noted.

Ting and team estimated that their sampled region is actually home to 754 to 1,502 elephants or .47 to .80 elephants per square kilometer. That data suggests the population in the corridor is between 3,033 to 6,043 elephants, based on abundance, or 1,684 to 2,832, based on their density - the two different metrics they used to model the population size.

"Gabon is thought to be a population stronghold of African forest elephants," Ting said. "But even our most optimistic results suggest a smaller population size than expected. Our research shows how endangered they really are if a region like this one is so overestimated."

It is hoped, Ting said, that his team's new findings can help inform government officials and conservation groups as they plan future conservation strategies.

"Our study emphasizes the threatened status of forest elephants and demonstrates the need for more research," Ting said. "It is imperative that known populations are monitored to provide accurate data on the status of these populations and the global forest elephant population as a whole."

WEST LAFAYETTE, Ind. -- Soft and flexible materials called halide perovskites could make solar cells more efficient at significantly less cost, but they're too unstable to use.

A Purdue University-led research team has found a way to make halide perovskites stable enough by inhibiting the ion movement that makes them rapidly degrade, unlocking their use for solar panels as well as electronic devices.

The discovery also means that halide perovskites can stack together to form heterostructures that would allow a device to perform more functions.

The results published in the journal Nature on Wednesday (April 29). Other collaborating universities include Shanghai Tech University, the Massachusetts Institute of Technology, the University of California, Berkeley, and the U.S. Department of Energy's Lawrence Berkeley National Laboratory.

Researchers already have seen that solar cells made out of perovskites in the lab perform just as well as the solar cells on the market made of silicon. Perovskites have the potential to be even more efficient than silicon because less energy is wasted when converting solar energy to electricity.

And because perovskites can be processed from a solution into a thin film, like ink printed on paper, they could be more cheaply produced in higher quantities compared to silicon.

"There have been 60 years of a concerted effort making good silicon devices. There may have been only 10 years of concerted effort on perovskites and they're already as good as silicon, but they don't last," said Letian Dou (lah-TEEN dough), a Purdue assistant professor of chemical engineering.

A perovskite is made up of components that an engineer can individually replace at the nanometer scale to tune the material's properties. Including multiple perovskites in a solar cell or integrated circuit would allow the device to perform different functions, but perovskites are too unstable to stack together.

Dou's team discovered that simply adding a rigid bulky molecule, called bithiophenylethylammonium, to the surface of a perovskite stabilizes the movement of ions, preventing chemical bonds from breaking easily. The researchers also demonstrated that adding this molecule makes a perovskite stable enough to form clean atomic junctions with other perovskites, allowing them to stack and integrate.

"If an engineer wanted to combine the best parts about perovskite A with the best parts about perovskite B, that typically can't happen because the perovskites would just mix together," said Brett Savoie (SAHV-oy), a Purdue assistant professor of chemical engineering, who conducted simulations explaining what the experiments revealed on a chemical level.

"In this case, you really can get the best of A and B in a single material. That is completely unheard of."

The bulky molecule allows a perovskite to stay stable even when heated to 100 degrees Celsius. Solar cells and electronic devices require elevated temperatures of 50-80 degrees Celsius to operate.

These findings also mean that it could be possible to incorporate perovskites into computer chips, the researchers said. Tiny switches in computer chips, called transistors, rely on tiny junctions to control electrical current. A pattern of perovskites might allow the chip to perform more functions than with just one material.

The COVID-19 shelter-in-place orders and other limitations could offer researchers the chance to use technology to decrease the digital divide and disparities in academic research, suggests a University of California, Davis, professor in a new commentary.

"While I know many of my colleagues are frustrated with this pause in clinical research, it is actually a unique opportunity," said Leigh Ann Simmons, chair of the Department of Human Ecology, whose research interests include increased equity in health care delivery and chronic disease prevention in rural areas. "People who live in rural areas are often left out of clinical trials that can benefit them, partly because they are not near large medical centers," she said. This includes migrant workers, farmers and the general public who live in outlying areas.

She is co-author of the commentary, "Navigating Nonessential Research Trials During COVID 19: The Push We Needed for Using Digital Technology to Increase Access for Rural Participants?" published in The Journal of Rural Health earlier this month. Co-author is Devon Noonan, a researcher at Duke University.

Simmons said some research in which research subjects have to be contacted personally for interviews, testing or surveys has stopped since social distancing went into effect. This is a mistake, she said. "If we think creatively we can extend our reach."

"We need to stop and think," said Simmons, who is herself currently engaged in two rural health prevention studies that are being conducted solely using remote strategies. "How can we do our work remotely? Is there a way to get our data without human contact? And if we go this route, how can we include people who may not usually participate in our studies?"

It is well known, the authors said in their paper, that rural populations experience significant health disparities, especially in rates of common chronic diseases such as heart disease, diabetes, cancer and the associated health behaviors such as diet, physical activity, and tobacco and other substance use. "These disparities are in part due to rural residents' lack of access to, knowledge about, and participation in clinical trials," they said.

Participation in such trials is made more difficult in these areas too by lack of good internet access. Simmons said this could be augmented by researchers using community centers or regional facilities, or other community partners, to enable access for those in the study. Regional facilities could also be used to help with data and sample collections.

Further, state departments of heath "could replicate the partnership that the California Department of Education initiated with Google to distribute mobile hotspots to areas without broadband access so that K-12 education could continue amid school closures associated with shelter-in-place orders," the authors suggest.

"Moving to remote clinical trials is not without its challenges, especially for studies that are well underway," she emphasizes. "Importantly, the steps we take now to continue nonessential research remotely may provide the evidence we need to ensure that future studies target these hard-to-reach populations for study inclusion."

Establishing remote access to clinical trials will serve to not only decrease rural clinical trial disparities, the authors said, but also to promote rural health equity into the next decade and beyond.

A supercell thunderstorm pelted a city center in Argentina a few years ago with hailstones so large scientists suggested a new category to describe them -- gargantuan hail.

Researchers investigating the 2018 storm found one hailstone likely measured between 7.4 and 9.3 inches across, potentially setting a new world record. The current record belongs to a hailstone that measured 8 inches across, or about the size of a volleyball, that fell near Vivian, South Dakota.

"It's incredible," said Matthew Kumjian, associate professor in the Department of Meteorology and Atmosphere Science at Penn State. "This is the extreme upper end of what you'd expect from hail."

The scientists proposed hail larger than 6 inches should be classified as gargantuan, and said more awareness of these events, while rare, could help piece together a better understanding of the dangerous storms.

"Anything larger than about a quarter in size can start putting dents into your car," Kumjian said. "In some rare cases, 6-inch hail has actually gone through roofs and multiple floors in houses. We'd like to help mitigate the impacts on life and property, to help anticipate these kinds of events."

The storm in heavily populated Villa Carlos Paz, Argentina, offered scientists a rare opportunity to study a well-documented case of gargantuan hail. As the storm unfolded, residents took to social media, posting pictures and videos.

Researchers followed up on the accounts a year later, interviewing witnesses, visiting sites where damage occurred, collecting photogrammetric data and analyzing radar observations. Using photogrammetry -- taking measurements from photographs -- and video evidence, the scientists estimated one hailstone may have set a world record.

The scientists reported their findings in the Bulletin of the American Meteorological Society.

"Such a well-observed case is an important step forward in understanding environments and storms that produce gargantuan hail, and ultimately how to anticipate and detect such extreme events," Kumjian said.

Hail typically occurs during severe storms, which produce strong, sustained updrafts. The winds hold hailstones aloft long enough to grow in sub-zero temperatures high in the atmosphere. But predicting hail size remains challenging, the scientists said.

Rachel Gutierrez, a graduate student at Penn State and co-author of the paper, found a connection between a storm updraft's rotational velocity, or how fast it is spinning, and larger hail size, but much remains unknown about the relationship.

She said the data, especially from a storm outside the United States, is invaluable.

"There typically isn't a lot of data from storms outside the U.S.," Gutierrez said. "Having this shows us these crazy, high-impact events can happen all over the world."

Gargantuan hail events may be more common than once believed, but researchers need volunteers willing to report hail and provide accurate measurements, either by including a common item for scale, or a ruler, Gutierrez said.

The ancient cemetery of Mözs-Icsei d?l? in present-day Hungary holds clues to a unique community formation during the beginnings of Europe's Migration Period, according to a study published April 29, 2020 in the open-access journal PLOS ONE by Corina Knipper from the Curt-Engelhorn-Center for Archaeometry, Germany, István Koncz, Tivadar Vida from the Eötvös Loránd University, Budapest, Hungary and colleagues.

As the Huns invaded Central Europe during the 5th century, the Romans abandoned their Pannonian provinces in the area of modern-day Western Hungary. Pannonia's population entered a period of continuous cultural transformation as new foreign groups arrived seeking refuge from the Huns, joining settlements already populated by remaining local Romanized population groups and other original inhabitants. (Later, the Huns themselves would fall to an alliance of Germanic groups.) To better understand this population changing rapidly under chaotic circumstances, Knipper and colleagues turned to the cemetery of Mözs-Icsei d?l? in the Pannonian settlement of Mözs, established around 430 AD.

The authors conducted an archaeological survey of the cemetery and used a combination of isotope analysis and biological anthropology to investigate the site's previously-excavated burials.

They found that Mözs-Icsei d?l? was a remarkably diverse community and were able to identify three distinct groups across two or three generations (96 burials total) until the abandonment of Mözs cemetery around 470 AD: a small local founder group, with graves built in a brick-lined Roman style; a foreign group of twelve individuals of similar isotopic and cultural background, who appear to have arrived around a decade after the founders and may have helped establish the traditions of grave goods and skull deformation seen in later burials; and a group of later burials featuring mingled Roman and various foreign traditions.

51 individuals total, including adult males, females, and children, had artificially deformed skulls with depressions shaped by bandage wrappings, making Mözs-Icsei d?l? one of the largest concentrations of this cultural phenomenon in the region. The strontium isotope ratios at Mözs-Icsei d?l? were also significantly more variable than those of animal remains and prehistoric burials uncovered in the same geographic region of the Carpathian Basin, and indicate that most of Mözs' adult population lived elsewhere during their childhood. Moreover, carbon and nitrogen isotope data attest to remarkable contributions of millet to the human diet.

Though further investigation is still needed, Mözs-Icsei d?l? appears to suggest that in at least one community in Pannonia during and after the decline of the Roman Empire, a culture briefly emerged where local Roman and foreign migrant groups shared traditions as well as geographical space.

A strange reversal of ground motion preceded two of the largest earthquakes in history. This is the result of a new study led by Jonathan Bedford of GFZ German Research Centre for Geosciences. Together with a diverse team of geoscientists from GFZ, FU Berlin, Chile, and USA, he investigated signals recorded in Chile and Japan capturing the movement of GNSS stations before the great Maule quake in 2010 (magnitude 8.8) and the Tohoku-oki earthquake in 2011 (magnitude 9.0) which led to a devastating tsunami and the Fukushima nuclear meltdown. The scientists publish their findings in the latest issue of the scientific journal Nature.

Using state of the art geodetic analyses, the team reports a vast, 1000 km-scale region of the Earth's surface close to the plate boundary alternating its sense of motion over a period of several months directly leading up to both earthquakes. Both events occurred at the Pacific rim where oceanic plates dive beneath the continental crust in a process called subduction. In Japan, a dense network of permanent stations is tracked by global navigational satellite systems (GNSS) with high precision so that researchers can observe how fast and in which direction the ground is moving. In Chile, the network is not as dense but still tracks most of the deforming continental plate. Normally, the stations on land move away ever so slightly from the subduction trench as the continental crust is squeezed and thus shortened. However, studying the time series of GNSS signals, the researchers found a reversal of direction: Suddenly the stations moved towards the subduction trench, i.e. towards the open ocean, and then reversed their direction again back to their normal movement (see animated gifs). Very shortly after this second reversal, the underground ruptured and the immense earthquakes occurred.

Aided by simple models and the best-known geological constraints, the authors propose that these reversals capture periods of enhanced pulling caused by rapid, densifying compositional changes in the oceanic plate as it subducts. Accordingly, it is suggested that these periods of enhanced tugging accelerated the inevitable failure at the shallower, frictionally-stuck segments of the subduction zone.

Jonathan Bedford explains: "It is a common assumption that deeper subduction proceeds at a fairly constant speed in between large earthquakes. Our study shows that this assumption is an oversimplification. In fact, its variability might be a key factor in understanding how the largest earthquakes nucleate."

Whether or not such strong reversals will occur before the next great earthquake remains to be seen, but what is clear from this study is that subduction zones are much more dynamic on the observable timescale than previously thought.

Macrophages are immune cells that patrol the body looking for potential threats like viruses, bacteria, and cancer cells, and engulf and destroy them. However, cancerous tumors have a nasty trick up their sleeves: they secrete substances that "switch" arriving macrophages from their tumor-killing state to a tumor-promoting state, in which they suppress the body's immune response, drive the growth of blood vessels to supply the tumor, and help the tumor metastasize. Efforts to extract macrophages from the body, force them into their tumor-killing state, and reintroduce them to fight cancer have failed, as the tumors relentlessly switch them back to their pro-tumor state.

Now, researchers at Harvard's Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS) have created a new solution to this problem: cytokine-secreting "backpacks" for macrophages that keep them in their tumor-killing state for up to five days after they arrive at a tumor site, and have been found to slow tumor growth and reduce metastasis in mice with an aggressive form of breast cancer. The results are published today in Science Advances.

"This study speaks to the beauty of macrophages - they are highly adaptable cells that respond very strongly to stimuli in their environment, but this can also be a problem when they receive a stimulus that tells them to do something that's actually harmful to the body, like helping cancer grow or metastasize," said first author C. Wyatt Shields, Ph.D., an Assistant Professor at the University of Colorado, Boulder who completed the study as a Postdoctoral Fellow in the lab of Wyss Core Faculty member Samir Mitragotri, Ph.D. "We have shown that it's possible to provide a sustained stimulus via these backpack particles to keep macrophages in their desired state, and we hope that this technique could one day be used to treat a variety of conditions related to immune dysfunction."

Building a better backpack

Macrophages are ravenous cells, binding to and eating anything they recognize as foreign to the body. Previous work from the Mitragotri lab showed that, surprisingly, small particles that are disc-shaped can hitch a ride on macrophages for several days without triggering their "eat me" response, and could offer an opportunity to influence the macrophages' behavior. For this study, the team constructed backpacks made of two layers of the biocompatible polymer poly(lactic-co-glycolic) acid (PLGA) with a "filling" of polyvinyl alcohol (PVA) and the cytokine interferon gamma (IFNγ) sandwiched between them. IFNγ is known to be a potent stimulator of the pro-inflammatory response in macrophages, and has been shown to reduce the sizes of some tumors. To finish off the backpacks, a final cell-adhesive layer was added to help them stick to their macrophage mounts.

Shields and his co-authors mixed macrophages with their backpack particles in vitro, and found that about 87% of the cells picked up one to four backpacks on their surfaces, which remained there for at least five days without being consumed and secreted IFNγ for at least 60 hours. They then tested the macrophages for various markers that indicated that they were in a proinflammatory (M1) state that combats tumors, or an anti-inflammatory (M2) state. Macrophages carrying IFNγ backpacks expressed three M1-associated traits much more strongly than macrophages with blank backpacks or macrophages in the presence of free IFNγ, while their expression of M2-associated traits did not change significantly. Their increased M1-trait expression also lasted longer than either of the control groups', suggesting that the IFNγ backpacks could induce a lasting shift to the M1 state.

Now it was time for the real test to see if their backpacks could succeed where previous studies had failed: maintaining macrophages in their M1 state after being introduced into live cancerous tumors. The researchers injected their backpack-toting macrophages into the tumors of mice with an aggressive form of metastatic breast cancer, then evaluated them after seven days. To their delight, macrophages carrying IFNγ backpacks expressed M1 indicators for at least 48 hours, and their expression levels were significantly higher than that of injected cells with blank backpacks or with free IFNγ. They also found that mice treated with the IFNγ backpack therapy had significantly fewer metastatic nodules and smaller tumors than control mice, and lived longer.

When the team dug deeper to find out what was happening within the tumors after they were injected with the IFNγ backpacks therapy, they found a surprising result: not only did the backpack-carrying macrophages stay in their M1 state, they actually helped other macrophages within the tumor (tumor-associated macrophages, or TAMs) revert from an anti-inflammatory M2 state back to an M1 state, effectively activating them to fight the tumors that had hijacked them to do their bidding. Furthermore, this result was achieved with a dose of IFNγ that is 100-fold lower than the maximum total dose used in other studies, and the mice did not display any signs of toxicity from the treatment.

"Macrophages can make up roughly 50% of the mass of a tumor. If we are able to switch them into their M1 state and sustain that activation, it could massively reduce the size of tumors and give both the immune system and treatments like chemotherapy better access to the cancer cells themselves," said Shields.

A control panel for living cells

In addition to producing a sustained pro-inflammatory response against tumors, the team's backpack approach could also be used to do the opposite: shift macrophages into an anti-inflammatory state in patients who are suffering from diseases associated with excess inflammation, such as rheumatoid arthritis, Crohn's disease, and lupus. Mitragotri's lab is continuing to explore different applications of this technology, including loading different agents into the backpacks and testing their ability to bind and control other types of cells.

"Improving drug delivery is a hot topic in biomedical research these days, and cells are one of the best vehicles for that because they can navigate through the body's defensive barriers and reach their target with high precision. The biggest challenge with introducing a living entity into the body for treatment is figuring out how to control it after it's injected, so that it does what you want it to do," said Mitragotri, who is also the Hiller Professor of Bioengineering and Hansjörg Wyss Professor of Biologically Inspired Engineering at SEAS and recently wrote a review article of different drug targeting approaches. "This study is a very strong proof-of-concept for a new way of controlling cells in vivo, and we think it could provide a versatile platform for treating numerous different conditions.

"Samir Mitragotri and his team are continuously inventing new ways to overcome the many barriers in the body that hamper drug efficacy. This study harnesses nature itself by using patients' own macrophages to deliver the drugs that are required to induce these cells to kill cancer cells. It represents an exciting new breakthrough in the Institute's approach to develop bioinspired therapeutics that will provide better and safer treatments for a wide range of human diseases," said Wyss Institute Founding Director Donald Ingber, M.D., Ph.D., who also is the Judah Folkman Professor of Vascular Biology at Harvard Medical School and Boston Children's Hospital, and Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).

What The Study Did: In this observational study, researchers examine internet searches indicative of shopping for chloroquine and hydroxychloroquine, including after high-profile endorsements.

Authors: John W. Ayers, Ph.D., M.A., of the University of California, San Diego, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamainternmed.2020.1764)

Editor's Note: The article includes conflict of interest disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflicts of interest and financial disclosures, and funding and support.

COLUMBUS, Ohio - The land masses of Japan shifted from east to west to east again in the months before the strongest earthquake in the country's recorded history, a 2011 magnitude-9 earthquake that killed more than 15,500 people, new research shows.

Those movements, what researchers are calling a "wobble," may have the potential to alert seismologists to greater risk of future large subduction-zone earthquakes. These destructive events occur where one of Earth's tectonic plates slides under another one. That underthrusting jams up or binds the earth, until the jam is finally torn or broken and an earthquake results.

The findings were published today (April 30) in the journal Nature.

"What happened in Japan was an enormous but very slow wobble - something never observed before," said Michael Bevis, a co-author of the paper and professor of earth sciences at The Ohio State University.

"But are all giant earthquakes preceded by wobbles of this kind? We don't know because we don't have enough data. This is one more thing to watch for when assessing seismic risk in subduction zones like those in Japan, Sumatra, the Andes and Alaska."

The wobble would have been imperceptible to people standing on the island, Bevis said, moving the equivalent of just a few millimeters per month over a period of five to seven months. But the movement was obvious in data recorded by more than 1,000 GPS stations distributed throughout Japan, in the months leading up to the March 11 Tohoku-oki earthquake.

The research team, which included scientists from Germany, Chile and the United States, analyzed that data and saw a reversing shift in the land - about 4 to 8 millimeters east, then to the west, then back to the east. Those movements were markedly different from the steady and cyclical shifts the Earth's land masses continuously make.

"The world is broken up into plates that are always moving in one way or another," Bevis said. "Movement is not unusual. It's this style of movement that's unusual."

Bevis said the wobble could indicate that in the months before the earthquake, the plate under the Philippine Sea began something called a "slow slip event," a relatively gentle and "silent" underthrusting of two adjacent oceanic plates beneath Japan, that eventually triggered a massive westward and downward lurch that drove the Pacific plate and slab under Japan, generating powerful seismic waves that shook the whole country.

That 2011 earthquake caused widespread damage throughout Japan. It permanently shifted large parts of Japan's main island, Honshu, several meters to the east. It launched tsunami waves more than 40 meters high. More than 450,000 people lost their homes. Several nuclear reactors melted down at the Fukushima Daiichi Nuclear Power Plant, sending a steady stream of toxic, radioactive materials into the atmosphere and forcing thousands nearby to flee their homes. It was the worst nuclear disaster since Chernobyl.

Researchers who study earthquakes and plate tectonics try to pinpoint the approximate magnitude of the next large earthquakes and predict where and when they might occur. The "when" is much harder than the "where."

But it won't be possible to use the findings of this study to predict earthquakes in some subduction zones around the world because they don't have the GPS systems needed, said Jonathan Bedford, lead author of this study and a researcher at the GFZ German Research Centre for Geosciences.

In 2011, Japan had one of the largest and most robust GPS monitoring systems in the world. That system provided ample data, and allowed the research team to identify the swing the land mass made in the months leading up to the earthquake.

Other countries, including Chile and Sumatra, which were hit by devastating earthquakes and tsunamis in 2010 and 2004, respectively, had much less-comprehensive systems at the time of those disasters.

The researchers analyzed similar data from the 2010 Chile earthquake, and found evidence of a similar wobble; Bedford said the data was "only just good enough to capture the signal."

"We really need to be monitoring all major subduction zones with high-density GPS networks as soon as possible," he said.