Tech

Baltimore (June 10, 2019) - Food production is an important contributor to climate change, accounting for about a quarter of carbon emissions globally. According to a study that examined the real-world diets of thousands of people in the U.S., we could greatly reduce the carbon footprint of what we eat by changing just one food each day.

"We found that making one substitution of poultry for beef resulted in an average reduction of dietary greenhouse gases by about a half," said lead study author Diego Rose, PhD, professor and director of nutrition at Tulane University.

Rose will present the research at Nutrition 2019, the American Society for Nutrition annual meeting, held June 8-11, 2019 in Baltimore.

"To our knowledge, this is the only nationally representative study of the carbon footprint of individually chosen diets in the U.S.," said Rose. "We hope this research will raise awareness about the role of the food sector in climate change and the sizable impact of a simple dietary change."

The new study is based on diet information from more than 16,000 participants in the 2005-2010 National Health and Nutrition Examination Survey. A portion of this survey asked participants to recall all the foods they consumed in the previous 24 hours. The researchers used this information to determine which foods had the highest greenhouse gas emissions and to calculate a carbon footprint for each individual diet.

They found that the 10 foods with the highest impacts on the environment were all cuts of beef and that about 20 percent of participants reported consuming one of these high-carbon foods. Using simulation, the researchers calculated a new carbon footprint for each diet by replacing beef with the closest related poultry product. For example, a broiled beef steak was replaced with broiled chicken and ground beef with ground turkey. Each substitution was performed only one time for each person that consumed one of the high-carbon foods.

Animal foods are known to contribute more to greenhouse gas emissions than plant foods. Ruminant animal foods such as beef and lamb have particularly high carbon footprints because cows and sheep also release methane gas.

"Our simulation showed that you don't have to give up animal products to improve your carbon footprint," said Rose. "Just one food substitution brought close to a 50% reduction, on average, in a person's carbon footprint."

The researchers plan to expand this research, which focused on dietary greenhouse gas emissions, to include other environmental impacts such as water use.

Although not the subject of this study, they point out that food waste and overeating also increase the carbon footprint of our diet. Thus, in addition to eating low-carbon foods, better meal planning and eating of leftovers can also help reduce carbon footprint.

Diego Rose will present this research on Monday, June 10, from 12:15 - 12:30 p.m. in the Baltimore Convention Center, Room 317 (abstract). Contact the media team for more information or to obtain a free press pass to attend the meeting.

How do you protect yourself from the perfect striking weapon? You develop the perfect shield.

If you're a mantis shrimp with a clublike arm tough enough to crack clamshells, you'd better not get into any fights with your pals. But the tiny crustaceans, among the ocean's feistiest creatures, can't resist taking swipes at each other over habitat, so they evolved a specialized shield in their tail segment called a telson that absorbs the blows. The telson is a multiscale structure with ridges on the outside and a structure shaped like a spiral staircase on the inside. It's inspiring a new class of lightweight, impact-resistant materials for helmets, cars, and more.

Research led by David Kisailus, the Winston Chung Endowed Professor in Energy Innovation at UC Riverside's Marlan and Rosemary Bourns College of Engineering; and Pablo Zavattieri, a professor and University Faculty Scholar at Purdue's Lyles School of Civil Engineering have unlocked the telson's secret -- with an eye toward creating better materials for sports, aerospace, and a multitude of other applications.

Kisailus, whose lab investigates biological composite structures as inspiration for new materials, said a paper by Duke University's Sheila Patek about the telson's ability to absorb energy, inspired him to investigate the role multiscale architectural features have on impact resistance.

Some species of mantis shrimp, called smashers because of their powerful dactyl club, inhabit cavities in coral reefs. Competition for the limited number of suitable caves is fierce and the mantis use their telson to protect themselves from devastating blows. Less aggressive types of mantis shrimp, called spearers -- after the appendage they use to stab prey -- also have a telson. Spearers live in the sand, which is abundant, and thus have fewer conflicts over habitat.

Kisailus, the lead researcher of a multi-university grant funded by the Air Force Office of Scientific Research, and his team initiated the studies of both the large-scale architecture as well as the internal structure of both types of telson and subjected each to mechanical testing. They found a helicoidal structure within this specialized shield that prevents cracks from growing and ultimately dissipates significant amounts of energy from strikes to avoid catastrophic failure. The helicoidal, or twisted plywood-like, structure is similar to one the researchers previously identified in the smasher's dactyl club that allows it to crack clamshells without breaking itself.

"For over a decade, we have been studying the dactyl club of the smashing type of mantis shrimp. We realized that if these organisms were striking each other with such incredible forces, the telson must be architected in such a way to act like the perfect shield," Kisailus said. "We found that not only did the telson of the smasher contain the helicoid microstructure, but there were significantly more layers in the smashing type than the spearing type."

Zavattieri added there is always a trade-off between amount of material required for protection and lightweight capacity for fast deployment as demonstrated by the smasher.

"Having access to one the most efficient materials architectures, such as the helicoid, in conjunction with a clever geometry, makes this another winner solution found by nature," he said.

The researchers also revealed the function of highly curved ridges, called carinae, that run the length of the telson in the smashing mantis by performing mechanical tests on the telson as well as 3D printed replicas of its structure.

"When we observed the carinae, it was obvious that they stiffened the telson along its long axis," Kisailus said. "However, we found that the carinae also allowed the telson to flex inward when forces were applied perpendicular to its long axis. This enabled us to discover the non-obvious function of these ridges, which was to absorb significant amounts of energy during a strike. Pablo's models then validated our hypotheses."

Zavattieri applied simple mechanics principles and computational modeling to understand the role of the carinae.

"We found that these geometrical features can lead to both stiffening or softening structural behavior. These competing mechanisms are in principle counter-intuitive, and there is still more to learn from these species," Zavattieri said. "Moreover, these principles can then be applied to applications where lightweight impact protection is needed."

Kisailus and his team have been incorporating the findings into development of highly impact-resistant materials for use in helmets and other structural materials.

"It is a very exciting time for us as we have engaged with multiple entities, including aerospace, sports, and automotive teams, who are interested in implementing this technology," Kisailus said. "Two of my team members are currently working with the Air Force Research Labs to make lighter, stronger materials."

RICHLAND, WASHINGTON, June 10, 2019 - A rapidly increasing percentage of the world's population is connected to the global information environment. At the same time, the information environment is enabling social interactions that are radically changing how and at what rate information spreads. As part of an effort to understand communication patterns and build a quantitative framework for how this information expands online, researchers at Pacific Northwest National Laboratory, a United States Department of Energy national laboratory, recently examined cryptocurrency discussion threads on Reddit. Their findings, presented at the Web Conference 2019, not only shed light on how cryptocurrency discussions spread but could inform artificial intelligence applications for modeling information spread across internet social environments to help identify and model criminal activities by state and non-state actors exploiting cryptocurrencies.

Every day, thousands of messages on Reddit [and elsewhere] contain discussions of cryptocurrencies. Some of these trigger follow-up discussions. Some lead to increased interest in a cryptocurrency -- not just a discussion of that cryptocurrency, but its actual price/value. Clearly, not all cryptocurrencies are equivalent -- and analyzing a set of them can reveal how bad actors might exploit those differences.

Led by PNNL data scientist, Dr. Svitlana Volkova, the team analyzed three years of discussions on Reddit from January 2015 to January 2018. The team measured the speed and scale of discussion spread related to Bitcoin, Ethereum, and Monero cryptocurrencies. Findings include:

On average, there are 3,600 comments posted each day for Bitcoin; 500 for Ethereum; and 380 for Monero.

Not every post triggered a discussion. The rate of ineffective posts--posts that do not receive any additional commentary--is up to 5x higher with Bitcoin and Ethereum than Monero.

People respond quicker to Bitcoin posts. For example, it takes on average 11 minutes for someone within the Bitcoin subreddit to comment; 20 minutes for Monero; and 27 minutes for Ethereum.

Bitcoin discussions grow the fastest, followed by Ethereum and then Monero.

Discussions around Monero have largest median lifetimes. Ethereum discussions have the largest possible lifetimes, and, Bitcoin discussions have the lowest median lifetime of the three coins.

"Cryptocurrencies are quite unique observable units of information in the way discussions about them spread across social platforms," said Volkova. "These social signals are quite useful, and by incorporating them with machine and deep learning, we intend to build predictive models that hit on causal relationships between different variables so we can explain model decision-making processes."

The findings gathered by Volkova and her colleagues, PNNL researchers Maria Glenski and Emily Saldanha, provide valuable insights into how information expands and evolves in social platforms. Likewise, by focusing on a specific social phenomenon, the team hopes to compare the spread of cryptocurrency discussions with other viral trends, such as the spread of computer vulnerabilities and misinformation.

A drug that targets the immune system can delay the onset of type 1 diabetes an average of two years in children and adults at high risk, according to findings from TrialNet's Teplizumab (anti-CD3) Prevention Study published in the New England Journal of Medicine.

With 28 study sites around the world, it is the largest clinical trial network ever assembled to discover ways to delay and prevent type 1 diabetes. Vanderbilt University Medical Center (VUMC) was the largest contributor with more than 20% of the study participants.

"The key point for the millions of people at risk to develop this disease is we now have the first immunotherapy that significantly delays the onset of type 1 diabetes," said Bill Russell, MD, TrialNet principal investigator and director of the Division of Pediatric Endocrinology and Diabetes at VUMC. "Eighty-five percent of the almost 3,000 patients in the Children's Diabetes Program at Vanderbilt have type 1 diabetes.

"And we know that relatives of people with type 1 diabetes are 15 times more likely to develop the disease than the general population, so this is particularly good news for them as well," he said.

Type 1 diabetes is an autoimmune disease that occurs when the body's immune system attacks and destroys insulin-producing beta cells in the pancreas, causing abnormal blood glucose (sugar) levels. Teplizumab is an immunotherapy drug designed to interfere with the body's immune destruction of its own beta cells.

Previous studies showed teplizumab prolonged insulin production in people recently diagnosed with type 1 diabetes, but this is the first study to test it in people at high risk for the disease.

"This is the first study to show any drug can delay type 1 diabetes diagnosis a median of two years in people at high risk," said Teplizumab Prevention Study Chair Kevan Herold, MD, professor of Immunobiology and Internal Medicine at Yale University. "As anyone with type 1 diabetes will tell you, every day you can delay this disease is important."

Participants chosen for the study each had a lifetime risk of clinical diagnosis nearing 100%. Fifty-five of the 76 study participants were under age 18 and all had a relative with type 1 diabetes, two or more type 1 diabetes autoantibodies and abnormal blood sugar levels.

"The subject population all had positive diabetes antibodies in their circulation, indicating that their immune systems were targeting their beta cells in the pancreas," Russell said. "They also had impaired glucose tolerance, meaning their glucose response to an oral glucose tolerance test was not normal but it wasn't yet in the diabetic range. We now call this stage 2 of type I diabetes."

Russell said people who are in stage 2, (antibodies plus impaired glucose tolerance) have an 85% likelihood of developing diabetes (stage 3) within five years.

Participants were randomly assigned to either the treatment group, which received a 14-day course of teplizumab, or the control group, which received a placebo. All participants regularly received glucose tolerance tests until the study was completed, or until they developed clinical type 1 diabetes - whichever came first.

Seventy-two percent of people in the control group developed clinical diabetes, compared to only 43% of the teplizumab group. The median time for people in the control group to develop clinical diabetes was just over 24 months, while the median time for the treatment group was 48 months.

TrialNet researchers will conduct additional studies to look for ways to extend the benefits of teplizumab.

"We are now exploring a full-blown prevention trial in people even earlier in the disease process," Russell said. "And also looking at delaying or preventing progression to stage 3."

JUNE 10, 2019, NEW YORK - A Ludwig Cancer Research study has deciphered a complex molecular conversation between cancer and immune cells that is key to orchestrating the successful invasion of tumors by T cells that kill cancer cells.

"We show that two key chemokines, CCL5 and CXCL9, are universally implicated in T cell infiltration across all solid tumors," said George Coukos, who directs the Lausanne Branch of the Ludwig Institute for Cancer Research and led the study. "Their simultaneous presence in tumors is a key requirement for the engraftment of T cells and the establishment of a T cell-inflamed tumor, also known as a 'hot tumor.'"

Chemokines, signaling proteins that mediate the traffic of various immune cells into the tumor microenvironment, help T-cells home in on tumors and can affect tumor immunity and therapeutic outcomes. But which chemokines are involved and how they interact with one another to that end was not well understood.

The study, published in the current issue of the journal Cancer Cell, identifies biomarkers of great relevance to cancer immunotherapy and could enable a more precise clinical classification of tumors. It could also inform the design of new kinds of cell based and other immunotherapies for cancer. "These findings have advanced our understanding of how the T cell attack on tumors is orchestrated naturally in T cell-inflamed tumors," said Denarda Dangaj, a postdoctoral researcher at Ludwig Lausanne who is first author of the paper.

This latest research was prompted by the Coukos lab's 2003 discovery that ovarian cancer patients whose tumors are infiltrated by killer (or CD8+) T cells--which destroy infected and cancerous cells--demonstrate improved survival. Other studies have found similar correlations in most solid tumors.

In the current study, Coukos and his team identified two chemokines, CCL5 and CXCL9, that are consistently associated with CD8+ T cell infiltration of solid tumors. They show that CCL5 is expressed by cancer cells, while CXCL9 is produced by other (so-called myeloid) immune cells known as macrophages and dendritic cells that are also present in the tumor. When cancer cells drop their production of CCL5, CXCL9 expression drops as well. This results in the progressive depletion of CD8+ T cells in tumors.

This loss of CCL5 expression in cancer cells, they found, correlates with a chemical modification to DNA that suppresses the expression of targeted genes--a mechanism known as epigenetic silencing. The researchers suggest the epigenetic silencing of CCL5 is an adaptive mechanism by which tumors escape immune attack.

Cancer cells have good reason to suppress CCL5: it attracts CD8+ T cells. The researchers show that when T cells drawn by CCL5 reach the tumor and are activated by cancer antigens, they release a signaling protein of their own called interferon gamma (IFNγ). This, they discovered, causes macrophages and dendritic cells that have congregated at the tumor to secrete CXCL9, which dramatically boosts the infiltration of the tumor by circulating T cells.

"CCL5 is the key chemokine determining whether a tumor will be T cell inflamed," Coukos said. "However, CCL5 expression alone is not sufficient, and CXCL9 is a major amplifier of T cell recruitment."

These findings suggest CCL5 and CXCL9 could be useful biomarkers for immunotherapy. Most notably, they could help identify patients whose tumors are infiltrated by activated T cells and are therefore more likely to be susceptible to immunotherapies like anti-PD1 antibodies.

The newly discovered mechanism of immune evasion too might be exploited for therapy. "Knowing that CCL5 silencing is reversible by the drug decitabine provides a strong rationale to combine that epigenetic therapy with PD1 blockade," says Coukos.

Visible imagery from NASA's Terra satellite provided confirmation of the development of Tropical Cyclone 02A in the Arabian Sea, Northern Indian Ocean.

On June 10, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Terra satellite provided a visible image of 02A that showed thunderstorms circling the low-level center. MODIS imagery also showed some clouds and thunderstorms were offset to the northwest of the center. That's a result of outside winds or vertical wind shear, blowing from the southeast and pushing some clouds to the northwest.

Satellite imagery revealed that the sea surface temperatures are warm enough to support further development of Tropical Cyclone 02A, and forecasters at the Joint Typhoon Warning Center expect some strengthening over the next couple of days.

At 11 a.m. EDT (1500 UTC) on Monday, June 10, 2019, Tropical Cyclone 02A was centered near 13.7 degrees north latitude and 70.8 east longitude. That puts the center about 350 nautical miles south-southwest of Mumbai, India. 02A was moving to the north-northwest at 8 knots (9 mph/15 kph). Maximum sustained winds were near 45 knots (52 mph/83 kph).

The Joint Typhoon Warning Center forecast noted that the storm is expected to peak on June 12 when maximum sustained winds reach 60 knots (69 mph/111 kph). "The cyclone is expected to continue tracking generally northward along the western periphery of a subtropical ridge (elongated area of high pressure) anchored over India, making landfall near Jamnagar around 96 hours [June 14] and track inland."

CI Tau b is a paradoxical planet, but new research about its mass, brightness and the carbon monoxide in its atmosphere is starting to answer questions about how a planet so large could have formed around a star that's only 2 million years old.

At today's meeting of the American Astronomical Society, astronomers Christopher Johns-Krull of Rice University and Lisa Prato of Lowell Observatory presented findings from a four-year near-infrared spectroscopic analysis of light from CI Tau b, a close-orbiting giant exoplanet, or "hot Jupiter," in a nine-day orbit around its parent star about 450 light years from Earth in the constellation Taurus.

"The exciting thing is that we are able to detect light directly from the planet, and it's the first time that's been done for a close-in planet around a star this young," said Johns-Krull, professor of physics and astronomy and co-author of a study that's slated for publication in AAS's Astrophysical Journal Letters. "The most valuable way to learn how planets form is to study planets, like CI Tau b, that are either still forming or have just formed."

For decades, most astronomers believed giant planets like Jupiter and Saturn formed far from their stars over periods of 10 million years or more. But the discovery of dozens of "hot Jupiters" led to new theoretical models that describe how such planets might form.

Johns-Krull said CI Tau b's age made it the perfect candidate for observation with the Immersion Grating Infrared Spectrograph (IGRINS), a unique, high-resolution instrument that was used during observations of CI Tau b from McDonald Observatory's 2.7-meter Harlan J. Smith Telescope and Lowell Observatory's 4.3-meter Discovery Channel Telescope.

Because each atomic element and molecule in a star emits light from a unique set of wavelengths, astronomers can look for specific signatures, or spectral lines, to see if an element is present in a distant star or planets. Spectral lines can also reveal the temperature and density of a star and how fast it's moving.

Prato said the research team used the spectral lines from carbon monoxide to distinguish the light emitted by the planet from the light emitted by the nearby star.

"Many of the spectral lines that are in the planet are also in the star," Prato said. "If both the planet and star were stationary, their spectral lines would all blend together, and we wouldn't be able to tell what was from the star and what was from the planet. But because the planet rapidly orbits the star, its lines shift back and forth dramatically. We can subtract out the star's lines and see only the lines from the planet. And from those, we can determine how bright the planet is, relative to the star, which tells us something about how it formed."

That's because the brightness of a star or planet depends upon both its size and temperature.

"Direct observational evidence of the mass and brightness of CI Tau b is particularly useful because we also know it orbits a very young star," said Rice Ph.D. student Laura Flagg, the lead author of the forthcoming study. "Most of the hot Jupiters we've found are orbiting middle-aged stars. CI Tau's age gives a tight constraint for putting models to the test: Can they produce a planet this bright and this massive in so little time?"

Flagg's analysis of spectral lines from carbon monoxide showed that CI Tau b has a mass of 11.6 Jupiters and is about 134 times fainter than its parent star. Prato said that provides strong evidence that it formed via a "hot start," a theoretical model that describes how gravitational instabilities could form giant planets more rapidly than traditional models.

Prato said the new study provides a unique empirical yardstick by which to measure competing theories.

"At about 2 million years old, CI Tau b is by far the youngest hot Jupiter directly detected," she said. "We now have a mass and brightness for it -- the only directly measured mass and brightness for a young hot Jupiter -- and that provides very strong tests for planet-formation models."

IGRINS, which was designed by study co-author Daniel Jaffe of the University of Texas at Austin, uses a silicon-based diffraction grating to improve both the resolution and number of near-infrared spectral bands that can be observed from distant objects like CI Tau b and its parent star. IGRINS was moved from McDonald to Lowell midway through the study.

Additional co-authors include Larissa Nofi and Joe Llama of Lowell Observatory, and Kendall Sullivan and Gregory Mace of both UT Austin and its McDonald Observatory. The research was supported by Rice, the National Science Foundation (AST-1461918, AST-1229522 and AST-1702267), UT Austin, the Korea Astronomy and Space Science Institute, NASA (18-XRP18_2-0138) and Lowell Observatory.

Research by neuroscientists at the University of Chicago shows how short-term, working memory uses networks of neurons differently depending on the complexity of the task at hand.

The researchers used modern artificial intelligence (AI) techniques to train computational neural networks to solve a range of complex behavioral tasks that required storing information in short term memory. The AI networks were based on the biological structure of the brain and revealed two distinct processes involved in short-term memory. One, a "silent" process where the brain stores short-term memories without ongoing neural activity, and a second, more active process where circuits of neurons fire continuously.

The study, led by Nicholas Masse, PhD, a senior scientist at UChicago, and senior author David Freedman, PhD, professor of neurobiology, was published this week in Nature Neuroscience.

"Short-term memory is likely composed of many different processes, from very simple ones where you need to recall something you saw a few seconds ago, to more complex processes where you have to manipulate the information you are holding in memory," Freedman said. "We've identified how two different neural mechanisms work together to solve different kinds of memory tasks."

Active vs silent memory

Many daily tasks require the use of working memory, information that you need to do something in the moment but are likely to forget later. Sometimes you actively remember something on purpose, like when you're doing a math problem in your head or trying to remember a phone number before you have a chance to write it down. You also passively absorb information that you can recall later even if you didn't make a point of remembering it, like if someone asks if you saw a particular person in the hallway.

Neuroscientists have learned a lot about how the brain represents information held in memory by monitoring the patterns of electrical activity coursing through the brains of animals as they perform tasks that require the use of short-term memory. They can then monitor the activity of brain cells and measure their activity as the animals perform the tasks.

But Freedman said he and his team were surprised that during certain tasks that required information to be held in memory, their experiments found neural circuits to be unusually quiet. This led them to speculate that these "silent" memories might reside in temporary changes in the strength of connections, or synapses, between neurons.

The problem is that it's impossible using current technology to measure what's happening in synapses during these "silent" periods in a living animal's brain. So, Masse, Freedman and their team have been developing AI approaches that use data from the animal experiments to design networks that can simulate how the neurons in a real brain connect with each other. Then they can train the networks to solve the same kinds of tasks studied in the animal experiments.

During experiments with these biologically inspired neural networks, they were able to see two distinct processes at play during short-term memory processing. One, called persistent neuronal activity, was especially evident during more complex, but still short-term, tasks. When a neuron gets an input, it generates a brief electrical spike in activity. Neurons form synapses with other neurons, and as one neuron fires it triggers a chain reaction to make another neuron fire. Usually, this pattern of activity stops when the input is gone, but the AI model showed that when performing certain tasks, some circuits of neurons would continue firing even after an input was removed, like a reverberation or echo. This persistent activity appeared to be especially important for more complex problems that required information in memory to be manipulated in some way.

The researchers also saw a second process that explained how the brain could keep information in memory without persistent activity, as they had observed in their brain recording experiments. It's similar to the way the brain stores things in long-term memory by making complex networks of connections among many neurons. As the brain learns new information, these connections are strengthened, rerouted, or removed, a concept known as plasticity. The AI models showed that during the silent periods of memory, the brain can use a short-term form of plasticity in the synaptic connections between neurons to remember information temporarily.

Both of these forms of short-term memory last from a few seconds up to a few minutes. Some of the information used in working memory may end up in long-term storage, but most of it fades away with time.

"It's like writing something with your finger on a fogged-up mirror instead of writing it with a permanent marker," Masse said.

Complementary fields of research

The study demonstrates how valuable AI has become to the study of neuroscience, and how the two fields inform each other. Freedman said that artificial neural networks are often more intelligent and easier to train on complex tasks when they are modeled after the real brain. This also makes biologically-inspired AI networks better platforms for testing ideas about functions of the real brain functions.

"These two fields are really benefitting one another," he said. "Insights from neuroscience experiments are helping create smarter AI and studying circuits in artificial networks is helping answer fundamental questions about the brain."

Two-dimensional (2D) materials - as thin as a single layer of atoms - have intrigued scientists with their flexibility, elasticity, and unique electronic properties, as first discovered in materials such as graphene in 2004. Some of these materials can be especially susceptible to changes in their material properties as they are stretched and pulled. Under applied strain, they have been predicted to undergo phase transitions as disparate as superconducting in one moment to nonconducting the next, or optically opaque in one moment to transparent in the next.

Now, University of Rochester researchers have combined 2D materials with oxide materials in a new way, using a transistor-scale device platform, to fully explore the capabilities of these changeable 2D materials to transform electronics, optics, computing and a host of other technologies.

"We're opening up a new direction of study," says Stephen Wu, assistant professor of electrical and computer engineering and physics. "There's a huge number of 2D materials with different properties - and if you stretch them, they will do all sorts of things."

The platform developed in Wu's lab, configured much like traditional transistors, allows a small flake of a 2D material to be deposited onto a ferroelectric material. Voltage applied to the ferroelectric -- which acts like a transistor's third terminal, or gate -strains the 2D material by the piezoelectric effect, causing it to stretch. That, in turn, triggers a phase change that can completely change the way the material behaves. When the voltage is turned off the material retains its phase until an opposite polarity voltage is applied, causing the material to revert to its original phase.

"The ultimate goal of two-dimensional straintronics is to take all of the things that you couldn't control before, like the topological, superconducting, magnetic, and optical properties of these materials, and now be able to control them, just by stretching the material on a chip," Wu says.

"If you do this with topological materials you could impact quantum computers, or if you do it with superconducting materials you can impact superconducting electronics."

In a paper in Nature Nanotechnology, Wu and his students describe using a thin film of two-dimensional molybdenum ditelluride (MoTe2) in the device platform. When stretched and unstretched, the MoTe2 changes from a low conductivity semiconductor material to a highly conductive semimetallic material and back again.

"It operates just like a field effect transistor. You just have to put a voltage on that third terminal, and the MoTe2 will stretch a little bit in one direction and become something that's conducting. Then you stretch it back in another direction, and all of a sudden you have something that has low conductivity," Wu says.

The process works at room temperature, he adds, and, remarkably, "requires only a small amount of strain - we're stretching the MoTe2 by only 0.4 percent to see these changes."

Moore's law famously predicts that the number of transistors in a dense integrated circuit doubles about every two years.

However, as technology nears the limits at which traditional transistors can be scaled down in size -- as we reach the end of Moore's law -- the technology developed in Wu's lab could have far-reaching implications in moving past these limitations as the quest for ever more powerful, faster computing continues.

Wu's platform has the potential to perform the same functions as a transistor with far less power consumption since power is not needed to retain the conductivity state. Moreover, it minimizes the leakage of electrical current due to the steep slope at which the device changes conductivity with applied gate voltage. Both of these issues -- high power consumption and leakage of electrical current -- have constrained the performance of traditional transistors at the nanoscale.

"This is the first demonstration," Wu adds. "Now it's up to researchers to figure out how far it goes."

One advantage of Wu's platform is that it is configured much like a traditional transistor, making it easier to eventually adapt into current electronics. However, more work is needed before the platform reaches that stage. Currently the device can operate only 70 to 100 times in the lab before device failure. While the endurance of other non-volatile memories, like flash, are much higher they also operate much slower than the ultimate potential of the strain-based devices being developed in Wu's lab.

"Do I think it's a challenge that can be overcome? Absolutely," says Wu, who will be working on the problem with Hesam Askari, an assistant professor of mechanical engineering at Rochester, also a co-author on the paper. "It's a materials engineering problem that we can solve as we move forward in our understanding how this concept works."

They will also explore how much strain can be applied to various two-dimensional materials without causing them to break. Determining the ultimate limit of the concept will help guide researchers to other phase-change materials as the technology moves forward

Wu, who completed his PhD in physics at the University of California, Berkeley, was a postdoctoral scholar in the Materials Science Division at Argonne National Laboratory before he joined the University of Rochester as an assistant professor in the Department of Electrical and Computer Engineering and the Department of Physics in 2017.

He started with a single undergraduate student in his lab -- Arfan Sewaket '19, who was spending the summer as a Xerox Research Fellow. She helped Wu set up a temporary lab, then was the first to try out the device concept and the first to demonstrate its feasibility.

Since then, four graduate students in Wu's lab --- lead author Wenhui Hou, Ahmad Azizimanesh, Tara Pen?a, and Carla Watson "have done so much work" to document the device's properties and refine it, creating about 200 different versions to this point, Wu says. All are listed with Sewaket as coauthors, along with Askari and Ming Liu of Xi'an Jiaotong University in China.

Antennas made of carbon nanotube films are just as efficient as copper for wireless applications, according to researchers at Rice University's Brown School of Engineering. They're also tougher, more flexible and can essentially be painted onto devices.

The Rice lab of chemical and biomolecular engineer Matteo Pasquali tested antennas made of "shear-aligned" nanotube films. The researchers discovered that not only were the conductive films able to match the performance of commonly used copper films, they could also be made thinner to better handle higher frequencies.

The results detailed in Applied Physics Letters advance the lab's previous work on antennas based on carbon nanotube fibers.

The lab's shear-aligned antennas were tested at the National Institute of Standards and Technology (NIST) facility in Boulder, Colorado, by lead author Amram Bengio, who carried out the research and wrote the paper while earning his doctorate in Pasquali's lab. Bengio has since founded a company to further develop the material.

At the target frequencies of 5, 10 and 14 gigahertz, the antennas easily held their own with their metal counterparts, he said. "We were going up to frequencies that aren't even used in Wi-Fi and Bluetooth networks today, but will be used in the upcoming 5G generation of antennas," he said.

Bengio noted other researchers have argued nanotube-based antennas and their inherent properties have kept them from adhering to the "classical relationship between radiation efficiency and frequency," but the Rice experiments with more refined films have proved them wrong, allowing for the one-to-one comparisons.

To make the films, the Rice lab dissolved nanotubes, most of them single-walled and up to 8 microns long, in an acid-based solution. When spread onto a surface, the shear force produced prompts the nanotubes to self-align, a phenomenon the Pasquali lab has applied in other studies.

Bengio said that although gas-phase deposition is widely employed as a batch process for trace deposition of metals, the fluid-phase processing method lends itself to more scalable, continuous antenna manufacturing.

The test films were about the size of a glass slide, and between 1 and 7 microns thick. The nanotubes are held together by strongly attractive van der Waals forces, which gives the material mechanical properties far better than those of copper.

The researchers said the new antennas could be suitable for 5G networks but also for aircraft, especially unmanned aerial vehicles, for which weight is a consideration; as wireless telemetry portals for downhole oil and gas exploration; and for future "internet of things" applications.

"There are limits because of the physics of how an electromagnetic wave propagates through space," Bengio said. "We're not changing anything in that regard. What we are changing is the fact that the material from which all these antennas will be made is substantially lighter, stronger and more resistant to a wider variety of adverse environmental conditions than copper."

"This is a great example of how collaboration with national labs greatly expands the reach of university groups," Pasquali said. "We could never have done this work without the intellectual involvement and experimental capabilities of the NIST team."

Around age six, we start learning how to tie our shoelaces, making knots that look like ribbons -- or possibly more complex forms, if we are a little clumsy. We use knots every day, but the type of knots we generally use are associated with physical objects, things we can touch.

Although it can be hard to image, light can also be shaped in ways that form knotted configurations, whose shape depends on the orbital angular momentum of the light. This parameter is responsible for making the beam of light twist around its own axis, generating different knot shapes, and expanding to a new degree of freedom that can carry valuable information.

Learning and mastering how to generate twisted light -- light with orbital angular momentum -- has been a thriving field of study for the past 20 years. Unlike spin angular momentum, which is associated with the polarization of light, orbital angular momentum is associated with the spatial distribution of the electric field. These two types of angular momentum can also be coupled, which results in a variety of light fields of different shapes with polarizations that change from point to point.

The behaviour of light also becomes richer when it passes from oscillating at one single frequency (monochromatic light) to vibrating at many different frequencies. This introduces a broad array of polarization states, each describing a shape that can be traced by the electric field of the light over time. Combining this wider space of possibilities with the spatial variations produced by the orbital angular momentum should produce even more room for interesting connections, but until now this has been an uncharted frontier: while there is a large body of research on structured light, it has been essentially focused on single-color fields.

In a recent study, published in two papers, joint collaborations by ICFO researchers have broken theoretical and experimental ground in this new field, uncovering new types of knots for twisted light and a new type of angular momentum.

In the first paper, published in Nature Photonics, ICFO researchers Emilio Pisanty, Gerard Jiménez Machado, Veronica Vicuña Hernández, Antonio Picón and Alessio Celi, led by ICREA Prof. at ICFO Maciej Lewenstein and UPC Prof. at ICFO Juan P. Torres, have designed a beam of light with a polarization state that forms three-lobed trefoils at each point, by combining light of different frequencies (w and 2w), and making the trefoils connect to each other in a way such that the light beam, as a whole, has the shape of a knot.

These beams also exhibit a new kind of angular momentum, associated with the unusual symmetry of the beams, which remain invariant under rotations -- but only when the polarization is rotated by a specific fraction of the rotation of the spatial dependence. They named this new quantity the torus-knot angular momentum, because of the type of knot in the beams.

The researchers also implemented these beams experimentally, using nonlinear crystals to generate the beams, and they designed a nonlinear polarization tomography scheme to measure the trefoil shapes traced by the electric field. Their measurements show the presence of a new type of optical singularity which is topologically protected and robust against perturbations, caused by the different orientation of the polarization trefoils at different points around a circularly-polarized center.

In the second paper, published in Physical Review Letters, ICFO researchers Emilio Pisanty and Antonio Picón, led by ICREA Professor at ICFO Maciej Lewenstein, in collaboration with researchers from the Laser Applications and Photonics group at the University of Salamanca and from CU Boulder, show that this new optical singularity can be applied to nonlinear optics, even at the high-intensity extremes and in non-perturbative situations.

There they show, via theoretical simulations, that the high-order harmonics produced by the torus-knot beams at ultra-high intensities preserve the coordinated symmetry of the driving laser, forming twisted spirals of ultra-short pulses of light, and that the torus-knot angular momentum is conserved in the interaction. This new symmetry is essential in understanding the production of shaped light at very short wavelengths, which can be used for novel applications in microscopy, lithography and spectroscopy.

The results of both studies provide new frameworks and results that advance the study of structured light and non-linear optics. On one hand, the researchers were able to find new conservation laws for non-linear optics which hold even in extreme situations where tens or hundreds of photons get combined to form single high-frequency photons. On the other, they analyzed the driving fields that make this possible and showed that they contain a new optical singularity, with a new degree of freedom that could be used to store valuable information, opening the possibility of using these new topologies of light for future communication applications, among others.

Monday, 10 June 2019 - A new study has found a pattern of molecules that appear in the blood before a seizure happens. This discovery may lead to the development of an early warning system, which would enable people with epilepsy to know when they are at risk of having a seizure.

Researchers at FutureNeuro, the SFI Research Centre for Chronic and Rare Neurological Diseases, hosted at RCSI (Royal College of Surgeons in Ireland) led the study, which is published in the current edition of the Journal of Clinical Investigation (JCI).

FutureNeuro and RCSI researchers have discovered molecules in the blood that are higher in people with epilepsy before a seizure happens. These molecules are fragments of transfer RNAs (tRNAs), a chemical closely related to DNA that performs an important role in building proteins within the cell. When cells are stressed, tRNAs are cut into fragments. Higher levels of the fragments in the blood could reflect that brain cells are under stress in the build up to a seizure event.

Using blood samples from people with epilepsy at the Epilepsy Monitoring Unit in Beaumont Hospital, Dublin and in a similar specialist centre in Marburg, Germany, the group found that fragment levels of three tRNAs "spike" in the blood many hours before a seizure.

"People with epilepsy often report that one of the most difficult aspects of living with the disease is never knowing when a seizure will occur," said Dr Marion Hogg, FutureNeuro investigator, Honorary Lecturer at RCSI, and the study's lead author.

"The results of this study are very promising. We hope that our tRNA research will be a key first step toward developing an early warning system."

Approximately 40,000 people in Ireland have epilepsy and one third of those do not respond to current treatments, meaning they continue to experience seizures. The World Health Organisation estimates that more than 50 million people worldwide have epilepsy.

"New technologies to remove the unpredictability of uncontrolled seizures for people with epilepsy are a very real possibility," said Professor David Henshall, Director of FutureNeuro and Professor of Molecular Physiology and Neuroscience at RCSI who was a co-author on the paper.

"Building on this research we in FutureNeuro hope to develop a test prototype, similar to a blood sugar monitor that can potentially predict when a seizure might occur."

BOSTON and LONDON - June 10, 2019. The first results were revealed from the largest ongoing scientific nutrition study of its kind today, led by an international team of leading scientists including researchers from King's College London, Massachusetts General Hospital and nutritional science company ZOE, showing that individual responses to the same foods are unique, even between identical twins.

Presented at both the American Society of Nutrition and the American Diabetes Association conferences, the findings demonstrate that old-fashioned, one-size-fits-all dietary guidelines are too simplistic and that a personalized approach to nutrition is likely to provide better long-term health benefits.

The researchers measured how blood levels of markers such as sugar, insulin and fat change in response to specific meals, along with data on activity, sleep, hunger and gut bacteria (microbiome) in thousands of participants in the US and UK, mostly pairs of twins.

ZOE is using machine learning techniques to analyze this wealth of detailed nutritional data and is developing a consumer test and app, giving people the power and confidence to choose the right foods that optimize their personal metabolism, control weight and maintain good health.

The team is also announcing a major expansion of its work in collaboration with scientists at Stanford and Tufts Universities. The next phase will recruit more than a thousand volunteers across the US who want to understand their own personal responses to food and contribute to cutting-edge nutritional science by taking part at home. Find out more at https://joinzoe.com.

This groundbreaking nutrition research project was born out of the Twins UK Study - a unique 25-year investigation of health and lifestyle in 14,000 twins led by Tim Spector, Scientific Founder of ZOE, Professor of Genetic Epidemiology at King's College London and author of The Diet Myth.

After realizing that genetically identical twins had very different food preferences and responses, Spector teamed up with technologists Jonathan Wolf and George Hadjigeorgiou to create ZOE, setting up a series of scientific studies in the US and Europe involving thousands of volunteer health enthusiasts and top researchers in the field of nutrition and health.

The key research findings presented at the ASN and ADA are:

1,100 UK and US adults (60% twins) were studied for two weeks of regular blood sugar (glucose) monitoring of blood sugar, insulin, fat levels (triglycerides) and other blood markers in response to a combination of standardized and freely chosen meals.

The results reveal a wide variation in blood responses to the same meals, whether they contained carbohydrates or fat.

For example, some participants had rapid and prolonged increases in blood sugar and insulin, which are linked to weight gain and diabetes. Others had fat levels that peaked and lingered in the bloodstream hours after a meal, raising the risk of developing heart disease.

This large variation is only partly explained by genetic factors (less than 50% for glucose, less than 30% for insulin and less than 20% for triglycerides) and there is only a weak correlation between an individual's responses to fat and carbohydrates.

Identical twins who share all their genes and most of their environment often had different responses to identical foods. The study also finds that identical twins shared just 37% of their gut microbes - only slightly higher than the 35% shared between two unrelated individuals.

Surprisingly, the proportions of nutrients such as fat, proteins and carbohydrates listed on food labels explain less than 40% of the differences between individuals' nutritional responses to meals with similar amounts of calories. There are also large differences in responses to the same meals depending on the time of day they are eaten.

The results suggest that personal differences in metabolism due to factors such as the gut microbiome, meal timing and exercise are just as important as the nutritional composition of foods, supporting the idea that simple nutritional labeling is insufficient for assessing food.

ZOE's machine learning algorithm makes predictions about an individual's personal nutritional response that is strongly correlated with real-life measurements, and will continue to improve as the company's dataset grows.

Professor Spector said, "The sheer scale and detail of our scientific project is such that for the first time we can explore tremendously rich nutrition data at the level of an individual. Our results surprisingly show that we are all different in our response to such a basic input as food. It was a real shock to see that even identical twins have such different responses."

Dr. Andrew Chan, Professor of Medicine at Harvard Medical School and a gastroenterologist at Massachusetts General Hospital said, "It is reassuring that our genetic makeup only partially explains how our bodies respond to food. This underscores that our metabolism is not fixed - we have the power to change it. One exciting avenue is to tailor our diets to the bacteria in our gut that helps us metabolize nutrients."

"For the first time, we're expanding large-scale nutritional research beyond blood sugar. These findings show that the responses to food of a number of key metabolic markers - including triglycerides, insulin and blood sugar - are highly individualized. No one has been able to combine data on this scale before," added Dr. Sarah Berry, Associate Professor in Nutritional Sciences at King's College London and Scientific Advisor at Zoe.

"For most of us, the food we eat is the most important medicine we take. And yet we are all profoundly confused about what is good for us. We believe that combining science and machine learning can solve this, by understanding for the first time our individual responses to food," said ZOE co-founder and CEO, Jonathan Wolf.

"We believe that everyone deserves to understand how they respond to food so that they can make confident decisions about what to eat and be in control of living a healthier and more enjoyable life," said ZOE co-founder and President, George Hadjigeorgiou.

Researchers from the Department of Prehistory and Archaeology at the University of Seville have studied the archaeological evidence of prehistoric societies in the Neolithic Period in the Iberian Peninsula from the perspective of gender. According to the results of their work, which address the analysis from the point of view of bioarchaeology and funerary archaeology, it was in the Neolithic that gender differences first appeared which meant male domination in later periods of history.

To arrive at these conclusions, the researchers have analysed two groups of indicators. On the one hand, life conditions and demographic aspects; and, on the other, funerary practices. In the first group, they studied factors like the sexual ratio (the demographic proportion of men to women), diet, genetic data, movement, the most common diseases and the detected stress markers. In the second, they considered data like the type of burial, the primary or secondary character of the deposit, if it was individual or collective burial, the spatial organisation of the site, the position and orientation of the bodies, the funerary goods that were placed in the tomb or the "funerary movements" (signs of manipulation of the bodies, pigmentation or alteration caused by the heat).

The study concluded that inequality between men and women was not generally consolidated or widely spread in Iberia during the Neolithic. However, situations progressively appeared that indicate dominance of men over women. The authors point to four important lines in which inequality between men and women can be investigated through successive historical periods: their access to funeral rites, the material conditions of their existence, the appearance of specific social roles for each of the genders and the growing association of men with violence.

It is precisely this last aspect that is most evident in this study. The arrow wounds on male bodies, the depositing of projectiles in their tombs or the pictorial representations (cave paintings) of men hunting and fighting have no equivalent parallel in women. Therefore, the authors point to the birth of an ideology that connected men with the exercise of force. In this sense, they highlight that the creation of different roles according to gender and other forms of gender inequality played a fundamental role in the growth of social complexity, a factor that has not always been well understood in previous research projects.

The study, which stems from the University of Seville doctoral thesis of Marta Cintas Peña, was carried out by the teacher Leonardo García Sanjuán, and it is the first time that this period has been dealt with from the perspective of gender and considering multiple variables. The study's conclusions mean the archaeological confirmation of the proposal of anthropologist Gerda Lerner, who in the book The Creation of Patriarchy proposed the hypothesis that it was the Neolithic societies that saw the beginning of inequality between men and women.

Strong family and school connections are helping prevent transgender youth from smoking cigarettes and using marijuana, even among those targeted by violence.

That's the key finding of a new national study led by researchers in the Stigma and Resilience Among Vulnerable Youth Centre (SARAVYC) in the school of nursing at the University of British Columbia.

The study analyzed data from 323 transgender youth ages 14 to 18 who took the 2014 Canadian Trans Youth Health Survey. Among trans youth who reported experiencing high amounts of violence, those who had no family support or caring friends had a 61 per cent probability of smoking tobacco. But that probability dropped to only 20 per cent among those with supportive family and friends.

In addition, youth who reported high family connectedness were about 88 per cent less likely to report smoking cannabis in the past month, compared to those who reported lower family connectedness. For trans adolescents with high levels of both family and school connectedness, the probability of marijuana use dropped to only two per cent.

"Trans youth in Canada face unacceptably high levels of violence, and this contributes to substance use," said UBC nursing professor Elizabeth Saewyc, the study's principal investigator and executive director of SARAVYC. "However, our research showed that even when transgender youth experience high levels of violence or discrimination, a supportive family and safe school make a difference."

Transgender youth reported experiencing an average of 11 out of 29 different types of violence, including bullying, sexual or physical abuse, cyberbullying, sexual harassment and discrimination. The study found that each additional type of violence increased the odds of marijuana use or binge drinking by 11 per cent, and tobacco use by 12 per cent.

However, youth who reported high levels of two protective factors, such as a supportive family and a safe school, had much lower probabilities of substance use than those with one or no protective factors.

"These findings suggest that supportive families and schools are integral to preventing substance use among transgender youth," said lead author Ryan Watson, an assistant professor at the University of Connecticut, who was a SARAVYC postdoctoral fellow when the research was conducted.

"While we should work to reduce stigma and violence against trans young people, our findings also point to the important role of supportive adults and friends. Caring adults at home and at school are just as essential for our trans adolescents as they are for all youth," he added.

The research, published in Preventive Medicine Reports, was funded by the Canadian Institutes of Health Research and the U.S. National Institute on Drug Abuse.