Researchers at UBC Okanagan are looking at ways to improve cell phone connectivity and localization abilities by examining “smart” surfaces that can bounce signals from a tower to customers to improve the link. A smart surface involves installing reflective elements on windows or panels on buildings in dense urban environments.

The goal, says Dr. Anas Chaaban, is to improve wireless services for millions of Canadians. Currently, he says, there are more than 12,000 wireless antenna towers. And yet, a lack of cell service is a common problem.

“The increasing use of mobile technologies across the world is necessitating research that unlocks potential new approaches within our existing infrastructure,” says Dr. Chaaban, an Assistant Professor at UBC Okanagan’s School of Engineering. “Even though cellphone towers line the rooftops of major cities, and handle the data and phone traffic of millions of Canadians each day, there are still gaps in service.”

Dr. Chaaban and his team at UBCO’s Communication Theory Lab have developed transmission schemes that would incorporate reconfigurable intelligent surfaces — smart surfaces — throughout urban centres to serve as reflectors within existing wireless networks.

A reconfigurable intelligent surface (RIS) is a panel of many individual reflective elements, each of which can modify an incoming signal and reflect it. This modification can be controlled with an electrical signal, which enables the RIS to improve the connection or generate signals that are useful for locating users in the network.

The researchers developed a new localization system where an RIS can work as a satellite to improve accuracy. By making a surface smart, it can bounce signals to cell phones which in turn can use these signals to generate an accurate estimate of location, he says. An accurate location estimate is not only useful for location services but also to improve transmission from the tower to the phone using optimized location-aware transmission schemes that also leverage the RIS.

“Users never expect to have a call drop, and they also expect lightning-fast data speeds,” he says. “But to accomplish this, the networks require constant updating.”

The researchers tested their theory using multiple modulated RISs that allow for the simultaneous localization of multiple users with low complexity for each RIS. They also developed and tested RIS-enabled transmission schemes that outperform existing schemes.

“We simulated the proposed localization protocol and demonstrated its effectiveness in an urban micro-cell street canyon scenario as an example,” he explains. “And the protocol works for multiple users simultaneously. Even in areas with intermittent service, data can be shared and users can be located and enjoy a reliable connection.”

Of the more than 350 former National Football League (NFL) players who were studied an average of 29 years after their playing career ended, those who reported experiencing concussion symptoms during their careers scored worse on assessments of episodic memory, sustained attention, processing speed and vocabulary. However, the number of concussions diagnosed by a medical professional or length of playing career had no observed effect on cognition.

A follow-up analysis compared the former players to more than 5,000 male volunteers in the general population who did not play professional football, which found that cognitive performance was generally worse for former players than nonplayers. While younger former players outperformed nonplayers on some tests, older retired players more likely to perform worse than controls on cognitive tasks.

The researchers who led the study said that their results underline the importance of tracking concussion symptoms as opposed to diagnosed concussions in research. This work also adds evidence to the impact a professional football career can have on accelerating cognitive aging.

“It is well-established that in the hours and days after a concussion, people experience some cognitive impairment. However, when you look decades out, the data on the long-term impact have been mixed,” said study senior author Laura Germine, PhD, director of the Laboratory for Brain and Cognitive Health Technology at McLean Hospital and associate professor of psychiatry at Harvard Medical School. “These new findings from the largest study of its kind show that professional football players can still experience cognitive difficulties associated with head injuries decades after they have retired from the sport.”

Concussion Symptoms Linked to Cognitive Performance

For the study, 353 retired NFL players completed hour-long neuropsychological tests through an online platform called TestMyBrain, which is supported by McLean Hospital and Harvard Medical School. Players were fully remote and completed tests on a laptop or desktop that included assessments that measured processing speed, visual-spatial and working memory, and aspects of short- and long-term memory and vocabulary.

Recollected concussion symptoms were measured by asking the players the number of times they experienced any one of the following symptoms following a blow to the head during play or practice: headaches, nausea, dizziness, loss of consciousness, memory problems, disorientation, confusion, seizure, visual problems or feeling unsteady on their feet. They were also asked whether they lost consciousness during their careers, and whether they were ever diagnosed with a concussion by a medical professional.

The results showed that the former players’ cognitive performance (for example, on memory tasks) was associated with recalled football concussion symptoms. For example, differences observed in visual memory scores between former players with the highest and lowest reported concussion symptoms were equivalent to the differences in cognitive performance between a typical 35-year-old and 60-year-old.

However, poor cognitive performance was not associated with diagnosed concussions, years of professional play or age of first football exposure. The researchers noted that many head injuries or sub-concussive blows may not have been diagnosed as concussions due to a lack of awareness at the time or underreporting of symptoms by players.

When comparing the retired players to a group of 5,086 men who did not play football, cognitive performance was generally worse for former players. On two tests of processing speed, age-related differences in cognitive performance were larger among the former player group than the nonplayer group, with older players performing worse.

These comparison data suggest that football exposure might accelerate age-related cognitive declines and produce greater disadvantages at older ages, according to the researchers, who added that more studies are needed to track cognitive performance in former players as they age. Another possibility is that improved awareness and management of head injuries may have spared younger retired players more than older ones. The researchers also noted that this comparative finding is limited by a lack of data on cognition prior to head injuries, and that more research is needed that closely matches former players and nonplayers and measures their cognitive performances across their lifetimes.

“For both former players and researchers, we can glean some important takeaways from this study,” said principal investigator of the Football Players Health Study, Ross Zafonte, DO. “Former players can support their cognitive health as they age by taking proactive steps, and continuing to consult with their providers and educate themselves on symptoms of head injury. For researchers and providers, these findings support efforts to develop ways to enhance diagnosis and define long-term sequalae of concussion.” Zafonte is president of Spaulding Rehabilitation Network, a Mass General Brigham sports medicine physician, and the Earle P. and Ida S. Charlton Professor and Chair of the Harvard Medical School Department of Physical Medicine and Rehabilitation.

“The Community Based Participatory Research (CBPR) approach taken in this study is where this field is heading,” said Germine. “We are grateful to the players and how much they have taught us. It would not have been possible to do a study like this without engaging and deeply involving their community.”

Research Driven by Input from Former NFL Players

The Football Players Health Study at Harvard University, launched in 2014, is a comprehensive research program dedicated to examining the multifactorial causes that impact the health of former NFL players. The research has been informed by the players themselves, who have provided input on the health concerns and conditions they face after a career in football. An interdisciplinary team of researchers from Harvard University and Harvard Medical School and its affiliated teaching hospitals, including those in the Mass General Brigham system, conduct research from neurology, cardiology, sports medicine, rehabilitation medicine, chronic pain and public health. While concussion and head injury are of paramount concern, the study examines all aspects of player health across the life span. Former players can find important resources to support their health in this section of the study’s website.

“This could shift the design strategy of mechanical systems away from the traditional approach of developing new and superior materials to developing surfaces that can actively adapt to reduce the damage,” says Professor Motoyuki Murashima.

The work was a collaboration between Murashima at Tohoku University’s Department of Mechanical Systems Engineering and colleagues at Nagoya University and the Korea Photonics Technology Institute in South Korea.

The research is focused on the potential of innovative materials possessing ‘morphing surfaces’, which can be changed depending on the environment they operate in. These materials are being developed by several research groups to mimic a common flexibility found in living systems, such as leaf surfaces that change in response to variations in humidity. One example in engineering, previously developed by Murashima and colleagues, is a surface composed of a diaphragm supported by hard substrate, with changes in stress pressure altering the surface morphologies.

The team developed an artificial intelligence procedure in which sensors analyse the friction between two surfaces. Having detected where damage is occurring, the procedure can then use the ‘morphing’ capacity of the surface to minimize the frictional contact with damaged regions.

“This is the first research in the world to use artificial intelligence to control the shape of morphing surfaces and successfully detect the position of damage on interacting surfaces,” says Murashima.

As the analysis and adjustment proceeded in simulated test cases, the researchers were able to achieve a steady reduction in the fluctuated friction caused by contact between affected parts of the material under investigation.

The proof-of-concept system used discs spinning within a cylinder. The crucial next step will be to move closer to situations in which the procedure could be applied to real engineering challenges, such as industrial machinery. The ultimate aim is to allow a wide range of machinery to operate with less routine wear and damage, achieving longer useful lifespans and cost savings due to less frequent part replacements.

“An important next step is to develop more sophisticated learning and control algorithms that will reduce the time needed to learn the characteristics of the analysed surfaces and therefore achieve more refined and speedier control that prevents damage,” says Murashima.

Kathy Meek, a professor in the College of Veterinary Medicine, and collaborators at Cambridge University and the National Institutes of Health have uncovered a previously unknown aspect of how DNA double-stranded breaks are repaired.

A large protein kinase called DNA-PK starts the DNA repair process; in their new report, two distinct DNA-PK protein complexes are characterized, each of which has a specific role in DNA repair that cannot be assumed by the other.

“It still gives me chills,” says Meek. “I don’t think anyone would have predicted this.”

Meek’s findings are published in Molecular Cell,a high-impact journal that covers core cellular processes like DNA repair.

How DNA double-stranded breaks are repaired

DNA, the blueprint of life, is shaped like a helix; however, DNA is surprisingly easy to damage. Ultraviolet light, for example, and many cancer therapies including ionizing radiation and other specific drugs can all cause damage to DNA. Sometimes, only one of the two strands break. Because the DNA is still held together by the second strand, cells can repair the DNA fairly easily — the cells just copy the information from the second strand.

It is more difficult for cells to repair DNA damage when both strands are broken. Information in the form of nucleotides can be lost and must be added back in before the DNA ends are rejoined. If a cell has multiple DNA double-stranded breaks, the DNA ends can be joined with the wrong partner. This type of mistake is often associated with many types of cancers.

Double-stranded breaks also can be more difficult to repair if DNA-damaging agents cause chemical modifications at the DNA ends. Damaged DNA ends are often referred to as “dirty” ends.

DNA-PK can help repair DNA double-stranded breaks in one of two ways. For breaks with missing information, it can target enzymes that can fill in missing nucleotides — sort of like a needle and thread stitching the DNA back together. For “dirty” ends, DNA-PK recruits enzymes that can cut off the damaged DNA so that the ends can be rejoined.

This much was already known, but a key question remained unanswered in the scientific literature — until now: how does DNA-PK know whether to fill in or cut off ends at a double-stranded break?

Discovery of two DNA-PK complexes: Fill in and cut off

Meek’s team and their collaborators previously published structural studies that revealed two different DNA-PK complexes, called dimers. While many molecular geneticists already suspected that DNA-PK helps hold DNA ends together during the rejoining process, many wondered why there would be two dimers, instead of just one.

In their new study, Meek and her collaborators discovered that the two distinct DNA-PK dimers have different functions; one complex recruits enzymes that fill in lost information, while the other activates cutting enzymes that remove “dirty” ends. The team also discovered that repair efficacy depends on equilibrium between the two dimers.

A newly published study of a stalagmite found in a cave in southern Wisconsin reveals previously undetected history of the local climate going back thousands of years. The new findings provide strong evidence that a series of massive and abrupt warming events that punctuated the most recent ice age likely enveloped vast swaths of the Northern Hemisphere.

The research, conducted by a team of scientists at the University of Wisconsin-Madison, appears March 2 in the journal Nature Geoscience. It’s the first study to identify a possible link between ice age warm-ups recorded in the Greenland ice sheet — known as Dansgaard-Oeschger events — and climate records from deep within the interior of central North America.

“This is the only study in this area of the world that is recording these abrupt climate events during the last glacial period,” says Cameron Batchelor, who led the analysis while completing her PhD at UW-Madison. Batchelor is now a postdoctoral fellow with the National Science Foundation working at the Massachusetts Institute of Technology.

The study is based on an exceptionally detailed chemical and physical analysis of a stalagmite that formed in the Cave of the Mounds, a tourist attraction and educational destination.

“At Cave of the Mounds our mission is to interpret this geologic wonder for our many annual visitors,” says Joe Klimczak, general manager of the cave, which is a designated national natural landmark. “We are thrilled to deepen our understanding of the cave thanks to this world-class research and very exciting results.”

The stalagmite Batchelor and her team analyzed grew extremely slowly — taking roughly 20,000 years to reach the length of a human pinky finger.

The finger-length subterranean rock formed from a complex process that began in the sky. Water that originally fell as precipitation from the atmosphere soaked into the ground and percolated through soil and cracks in bedrock, dissolving tiny bits of limestone along the way. Some of that dissolved limestone was then left behind as countless drips of water fell from the ceiling of Cave of the Mounds, gradually accumulating into thousands of exceedingly thin layers of a mineral called calcite.

“And because those calcite layers are formed from that original precipitation, they’re locking in the oxygen in the H₂O originating from that precipitation,” says Batchelor.

Therein lies the key to reconstructing an ancient climate record from a small, otherwise unremarkable rock. The oxygen trapped in the calcite exists in a couple varieties — known as isotopes — that scientists can use to glean information about the environmental conditions present during the precipitation events that formed it. That includes the temperature and possible sources of rain and snow that fell atop the Cave of the Mounds over thousands of years.

Batchelor’s team used a specialized imaging technique that allowed them to identify layers within the stalagmite representing annual growth bands — much like how tree rings record a season’s worth of growth. Using another technique, they identified the isotopes in the tiny layers, revealing that present-day southern Wisconsin experienced a number of very large average temperature swings of up to 10 C (or about 18 F) between 48,000 and 68,000 years ago. Several of the temperature swings occurred over the course of around a decade.

While the dating information is not precise enough to definitively tie the temperature swings to the Dansgaard-Oeschger events recorded in Greenland ice cores, the researchers can say with confidence they occurred within similar timeframes. The team also performed climate simulations that bolstered the hypothesis that warming events occurred tens of thousands of years ago in the region of North America that includes present-day Wisconsin, and that the climate records from Cave of the Mounds and the Greenland ice sheet are indeed linked.

This potential link is exciting for Batchelor because it offers a climate story about central North America that has so far gone untold. Previous research from the mid-continent has not resolved signals of these large temperature swings, also called excursions.

“One theory was that the mid-continent is relatively immune to abrupt climate changes, and that maybe that’s because it’s surrounded by landmass, and there’s some type of buffering happening,” says Batchelor. “However, when we went and measured, we saw these really large excursions, and we were like, ‘Oh, no, something is definitely happening.'”

That something — a rapidly changing climate — is unfolding yet again today, thanks to humans and our use of fossil fuels. Batchelor says she hopes her work in Wisconsin, and now a cave in the Canadian subarctic that she is studying for her postdoc, helps fill a big data gap about the history and potential future of abrupt climate changes in the mid-continent of North America.

This study was supported by grants from the National Science foundation (P2C2-1805629, EAR-1355590, EAR-1658823). Further resources were provided by the U.S. Department of Energy (DE-AC05-00OR22725), the Wisconsin Alumni Research Foundation and the Isotope Laboratory at the University of Minnesota. At UW-Madison, Shaun Marcott, Ian Orland and Feng He contributed to this study, as did R. Lawrence Edwards at the University of Minnesota.