Tech

Quantum holds the promise of increasing the power of sensing technologies. While the field of quantum sensing has shown a lot of potential for detecting very small signals, the ability to truly optimize these sensors has been thwarted by the complexity of control schemes.

In a paper published on March 25 in Nature Partner Journals - Quantum Information, a research team based at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, explained how they applied two theoretical tools of quantum information to these types of extremely sensitive signal detection tasks. Their research suggests that honing this sensitivity to detect signals while rejecting background noise will enable the use of quantum detectors even when this surrounding noise is strong relative to the signal of interest.

"This field has seen a lot of recent interest through theoretical progress and impressive experimental results on a variety of platforms," said Paraj Titum, a quantum scientist in APL's Research and Exploratory Development Department and the lead author of the paper. "Our results are readily implementable in a variety of quantum computing and quantum sensing platforms such as superconducting qubits, NV-diamonds, and Silicon Carbide."

The authors applied filter functions and optimal quantum control theories to a use case of quantum bit (qubit) sensors that mirror a classic problem in signal detection theory: optimal detection of a known signal from background noise with a controllable quantum sensor. The research team obtained analytical insight into the optimal control protocol when the background noise is white.

"This turned out to be the ubiquitous spin-locking control scheme," Titum said. "More generally, we developed a simple numerical technique for arbitrary signal and background noise." This is similar to the well-known matched filtering scheme that is the optimal method to use in classical signal processing.

The APL team already has plans to explore this scheme in detecting realistic signals in an experimental setting. Another promising theoretical path they plan to explore is the use of quantum entanglement to enhance detection likelihood as compared with classical sensors.

University of Texas at Dallas researchers have discovered that a novel surface they developed to harvest water from the air encourages tiny water droplets to move spontaneously into larger droplets.

When researchers placed microdroplets of water on their liquid-lubricant surface, the microdroplets propelled themselves to climb, without external force, into larger droplets along an oily, ramp-shaped meniscus that forms from the lubricant around the larger droplets. The "coarsening droplet phenomenon" formed droplets large enough for harvesting.

"This meniscus-mediated climbing effect enabled rapid coalescence on hydrophilic surfaces and has not been reported before. We have discovered a new physical phenomenon that makes it possible to harvest water more rapidly from air without external force," said Dr. Xianming Dai, assistant professor of mechanical engineering in the Erik Jonsson School of Engineering and Computer Science, who led the work. "If we don't have this new phenomenon, the droplets would be too small, and we could hardly collect them."

Microdroplets of water on a hydrophilic SLIPS surface (left) propel themselves to climb, without external force, into larger droplets along an oily, ramp-shaped meniscus that forms from the lubricant around the larger droplets. On the right, the video clip shows how microdroplets behave on a solid slippery surface.

The findings, published March 25 in Cell Reports Physical Science, could solve key problems in harvesting water from air. Many droplets that condense from water vapor in the air are too small to be collected, and they can cover a surface in a way that impedes further condensation.

Developing new technologies that harvest water from the atmosphere is a growing field of research as more and more people live in areas where fresh water is in short supply. Scientists estimate that 4 billion people live in regions with severe freshwater shortages for at least one month each year. This number is predicted to rise to between 4.8 billion and 5.7 billion by 2050. Reasons include climate change, polluted water supplies and increased demand due to both population growth and changes in usage behavior.

The key to the microdroplet's self-climbing action is a surface that Dai and his colleagues previously developed. Their liquid lubricant, a hydrophilic slippery liquid-infused porous surface (SLIPS), has a unique hydrophilic nature for water harvesting and rapidly directs water droplets into reservoirs.

Researchers discovered the self-propelling droplet phenomenon on their surface by accident. They were testing different lubricants to determine which could best facilitate water harvesting when they saw the smaller water droplets propel themselves into larger droplets. That led them to collaborate with Dr. Howard A. Stone, chair of mechanical and aerospace engineering at Princeton University and an expert in fluid dynamics, to investigate the underlying physics of the phenomenon.

"Dr. Dai and his team led this work. The ideas are creative, and they made a series of observations in the laboratory that allowed them to understand the underlying physics and its potential applications," Stone said. "They reached out to me to discuss the mechanism, and we had several Skype or Zoom meetings and email exchanges. It was all very interesting and stimulating. I enjoyed very much seeing the ideas evolve into the published paper."

As water vapor condenses on the liquid-lubricant surface, oil from the lubricant forms a meniscus, or curvature, around the droplets. The meniscus looks like an upward-curving ramp, which acts like a bridge along which microdroplets spontaneously climb toward and coalesce with larger water droplets, a process the researchers call the coarsening effect. The properties of the lubricated surface prevent the water droplets from being completely submerged in the oil, so they can float on the oil, allowing them to climb.

"The oil meniscus acts like a bridge, so the droplet can climb on it," Dai said. "The small droplet actively looks for a larger one. After they are connected by the bridge, they become one."

As tiny water droplets condense from air on a cooled surface, they become thermal barriers that prevent further condensation. By allowing for rapid water droplet collection, the coarsening droplets help clear surfaces for new droplets to form, which facilitates faster, more efficient water harvesting.

The self-propelled coarsening droplet on hydrophilic SLIPS shows rapid removal of condensed submicrometer-sized droplets regardless of how the surface is oriented, which presents a promising approach compared to other surfaces used for water harvesting.

"We cannot harvest a large amount of water unless we have a rapid harvesting process. The problem with other surfaces is that the small water droplets may evaporate before they can be harvested," Dai said.

"Based on our experimental data, the coarsening surface enhanced the water harvesting rate 200% higher than its counterparts," said Zongqi Guo, a mechanical engineering doctoral student and co-lead author.
Dai and his colleagues continue to work on ways to use their lubricant to make sustainable water harvesting systems that are mobile, smaller in size, lower in weight and less expensive.

"If we can do that, we can harvest water anywhere that has air, which is particularly important in regions where water is scarce," Dai said.

WASHINGTON - A food preservative used to prolong the shelf life of Pop-Tarts, Rice Krispies Treats, Cheez-Its and almost 1,250 other popular processed foods may harm the immune system, according to a new peer-reviewed study by Environmental Working Group.

For the study, published this week in the International Journal of Environmental Research and Public Health, EWG researchers used data from the Environmental Protection Agency's Toxicity Forecaster, or ToxCast, to assess the health hazards of the most common chemicals added to food, as well as the "forever chemicals" known as PFAS, which can migrate to food from packaging.

EWG's analysis of ToxCast data showed that the preservative tert-butylhydroquinone, or TBHQ, has been found to harm the immune system both in both animal tests and in non-animal tests known as high-throughput in vitro toxicology testing. This finding is of particular concern during the coronavirus pandemic.

"The pandemic has focused public and scientific attention on environmental factors that can impact the immune system," said Olga Naidenko, Ph.D., EWG vice president for science investigations and lead author of the new study. "Before the pandemic, chemicals that may harm the immune system's defense against infection or cancer did not receive sufficient attention from public health agencies. To protect public health, this must change."

TBHQ

TBHQ is a preservative that is pervasive in processed foods. It has been used in foods for many decades and serves no function besides increasing a product's shelf life. Using new non-animal test results from ToxCast, EWG found that TBHQ affected immune cell proteins at doses similar to those that cause harm in traditional studies. Earlier studies have found that TBHQ might influence how well flu vaccines work and may be linked to a rise in food allergies.

PFAS

Using ToxCast, EWG analyzed all publicly available studies that show how PFAS migrate to food from packaging materials or processing equipment. This is the first known compilation of available research on PFAS migration from packaging to food. In 2017, nationwide tests showed that many fast-food chains used food wrappers, bags and boxes coated with highly fluorinated chemicals.

Human epidemiological studies show that PFAS suppresses immune function and decreases vaccine efficacy. Recently published research has also found a link between high levels of PFAS in the blood and the severity of Covid-19.

Surprisingly, for most PFAS, the ToxCast results did not match previous animal and human test data. This illustrates the limitations of this new chemical testing method. More research is needed to understand how PFAS harm the immune system.

Food Chemicals Regulation

The Food and Drug Administration's approach to the regulation of food additives does not consider the latest science on the health harms of additives that may be legally added to processed foods manufactured in the U.S. Last year, EWG published Food Additives State of the Science, which highlighted additives known to increase the risk of cancer, harm the nervous system and disrupt the body's hormonal balance.

Chemicals linked to health harms can be legally added to packaged foods because the FDA frequently allows food manufacturers to determine which chemicals are safe. Additives like TBHQ were approved by the FDA decades ago, and the agency does not consider new science to reassess the safety of food chemicals.

"Food manufacturers have no incentive to change their formulas," said Scott Faber, senior vice president for government affairs at EWG. "Too often, the FDA allows the food and chemical industry to determine which ingredients are safe for consumption. Our research shows how important it is that the FDA take a second look at these ingredients and test all food chemicals for safety."

Less Toxic Food Preservatives

Processed foods can be made without these potentially harmful ingredients, so shoppers should read labels carefully. TBHQ is often, though not always, listed on the ingredient label. It will be listed if it has been added to the product during manufacturing. But it can also be used in food packaging, particularly plastic packaging, in which case it may migrate to food.

EWG's Food Scores database helps consumers find products made with healthier alternatives, and our Healthy Living app allows shoppers to scan products while in stores to choose a better option.

EWG recommends that immunotoxicity testing be prioritized for chemicals in food and food contact materials in order to protect public health from their potential harm to the immune system.

EWG also calls on the FDA to close the regulatory loophole that allows potentially unsafe food additives to remain on the market. The FDA should also promptly review additives like TBHQ to reflect new science.

The thermodynamic state of the tropical atmosphere plays an important role in the development of tropical cyclone (TC) intensity. A TC imports thermodynamic energy from ocean-air heat and moisture fluxes and exports heat aloft at the much colder upper troposphere, through a radially and vertically directed overturning circulation in a TC. The work done through this cycle drives the TC's winds.

A negative response of cloud water in the lower troposphere to dust aerosol optical depth (AOD) has recently been reported in Atmospheric and Oceanic Science Letters (https://doi.org/10.1016/j.aosl.2020.100028) by Dr. Zhenxi Zhang from the Inner Mongolia University of Technology, Hohhot, China, by analyzing MERRA-2 reanalysis data and GCM simulations from CMIP6.

"The explanation of this response could be that dust aerosols absorb solar radiation, promoting the evaporation of clouds. In principle, this aerosol-driven vaporization modification could affect the enthalpy of the air surrounding a tropical cyclone", explains Dr. Zhang.

According to Zhang's study, a negative association between eastern Pacific TC intensity in offshore regions and dust AOD for the years 1980-2019 was also found. "The changes in TC intensity related to dust AOD conditions should be a consequence of the anomalous enthalpy of the air surrounding a TC caused by the negative effect of dust on cloud water", concludes Zhang.

WEST LAFAYETTE, Ind. - A Purdue University innovator has developed a new approach to creating popular thin films used for devices across a broad range of fields, including optics, acoustics and electronics.

Epitaxial lithium niobate (LNO) thin films are an attractive material for electronics and other devices. These films offer flexibility and other properties that are important to manufacturers.

The challenge is that these devices demand high-quality thin films that can be difficult to grow and produce. Haiyan Wang, a Purdue materials engineer, developed a new approach to creating these films. The work is published in Advanced Photonics Research.

"We created an approach that makes these films easier to produce," said Wang, the Basil S. Turner Professor of Engineering in Purdue's College of Engineering. "We developed a versatile nanocomposite-seeded approach that allows us to create single-layer films. Typically, engineers have used a double-layer approach, which adds to the complicated production process."

This work is supported by Sandia National Laboratories through its Academic Alliance initiative. This technology work also is supported through Sandia's Diversity Initiative.

"Our approach offers an efficient new option for optics, acoustics and electronics," said Robynne Paldi, a Ph.D. candidate at Purdue who helped lead the research. "Our films are grown through a pulsed laser deposition method and growth conditions are optimized to achieve high-quality films that can be easily integrated into devices."

The innovators worked with the Purdue Research Foundation Office of Technology Commercialization to patent their technology.

Throughout the world, societies discriminate against and mistreat members of certain social groups. Young children may express intergroup biases that lead to such outcomes, demonstrating preferences for their own over other groups. How these biases develop is an important topic of study in today's climate. A new longitudinal study mimicked a situation in which children might overhear derogatory messages about a new social group. The study revealed that overhearing a stranger's negative claims about a social group, even in a brief comment, can have a lasting influence on children's attitudes towards the group.

The findings were published in a Child Development article, written by researchers at Vanderbilt University.

"Findings from our work suggest that overhearing a negative conversation about an unfamiliar social group may influence intergroup biases among older children," says Emily Conder, the study's lead author and doctoral candidate at Vanderbilt University. "Caregivers should consider what is said around children and regulate the media they consume, as what children overhear about groups of people can influence their attitudes and behaviors."

The study included 121 children from primarily White, middle-class families in Nashville, Tennessee , 48 percent of whom were female, and who were recruited from local charter schools or through Tennessee state birth records. Consent forms were required for participation and were completed by a diverse group of parents who self-reported identifying as: White (67%), Black (19%), Asian (3%), or as multiple races or ethnicities (11%). Demographic data were not collected from or about child participants.

Participating children met individually with a female experimenter. With parental consent, the sessions were recorded with a camera hidden either in decorative plants or a pencil box. The procedure included the following:

Children played an unrelated game while they overheard an experimenter receive a pre-recorded Skype video call from either a child or adult caller.

During the pre-recorded video conversation, the researcher mentioned one of two novel groups, "Flurps" or "Gearoos."

Each participant was randomly assigned to a message condition (negative-message vs. no message) and a caller condition (adult vs. child). In the negative-message condition, the caller briefly provided negative information about the new group, such as "The Flurps are bad people. They eat disgusting food and they wear such weird clothes."

Children's attitudes about the group were measured immediately after the call, and their attitudes were measured again two weeks later, by a different researcher.

At the conclusion of the 2-week study, children were debriefed by a researcher and were told that "Gearoos" and "Flurps," "were not real groups of people, but if they were real, they would probably be very nice people."

Later, researchers analyzed the following measures of children's attitudes about the novel group:

Goodness evaluations: children's evaluation of the group's "goodness"

Cultural engagement: children's willingness to engage with elements of the group's culture (for example, to eat their food or wear their clothing).

Friendship decisions: children's willingness to be friends with someone from the group

Social distance: children were asked to draw themselves and a "Flurp" or "Gearoo" person while the experimenter pretended to check her email on a laptop to limit influence. Larger distances between drawings were interpreted as indicating stronger, negative attitudes toward the group.

Resource allocation: children's willingness to share stickers with the group.

Older children (7-9 years) who overheard the negative messages drew themselves further from the new group member, were less willing to be friends with someone from the group, rated the group as being less good, and were willing to try fewer elements of the group's culture than children who heard no claims about the group. These effects lasted for at least 2 weeks after children heard the messages. The messages had little to no effect on younger children (4-5 years), perhaps indicating that younger children find this type of social information less interesting or relevant. Contrary to the researchers' predictions, the age of the video caller (whether they were a child or an adult) did not have an impact on children's attitudes.

The authors suggest that future studies investigate how children's attitudes are affected if video callers speak directly to them, and how their attitudes are affected by specific aspects of the messages. The authors also advocate for research on the influence of positive messages about new social groups, to identify the extent to which they may reduce or counter the development of negative biases toward others.

During the COVID-19 pandemic, people have grown accustomed to wearing facemasks, but many coverings are fragile and not easily disinfected. Metal foams are durable, and their small pores and large surface areas suggest they could effectively filter out microbes. Now, researchers reporting in ACS' Nano Letters have transformed copper nanowires into metal foams that could be used in facemasks and air filtration systems. The foams filter efficiently, decontaminate easily for reuse and are recyclable.

When a person with a respiratory infection, such as SARS-CoV-2, coughs or sneezes, they release small droplets and aerosolized particles into the air. Particles smaller than 0.3 μm can stay airborne for hours, so materials that can trap these tiny particles are ideal for use in facemasks and air filters. But some existing filter materials have drawbacks. For example, fiberglass, carbon nanotubes and polypropylene fibers are not durable enough to undergo repeated decontamination procedures, while some further rely on electrostatics so they can't be washed, leading to large amounts of waste. Recently, researchers have developed metallic foams with microscopic pores that are stronger and more resistant to deformation, solvents, and high temperatures and pressures. So, Kai Liu and colleagues wanted to develop and test copper foams to see if they could effectively remove submicron-sized aerosols while also being durable enough to be decontaminated and reused.

The researchers fabricated metal foams by harvesting electrodeposited copper nanowires and casting them into a free-standing 3D network, which was solidified with heat to form strong bonds. A second copper layer was added to further strengthen the material. In tests, the copper foam held its form when pressurized and at high air speeds, suggesting it's durable for reusable facemasks or air filters and could be cleaned with washing or compressed air. The team found the metal foams had excellent filtration efficiency for particles within the 0.1-1.6 μm size range, which is relevant for filtering out SARS-CoV-2. Their most effective material was a 2.5 mm-thick version, with copper taking up 15% of the volume. This foam had a large surface area and trapped 97% of 0.1-0.4 μm aerosolized salt particles, which are commonly used in facemask tests. According to the team's calculations, the breathability of their foams was generally comparable to that of commercially available polypropylene N95 facemasks. Because the new material is copper-based, the filters should be resistant to cleaning agents, allowing for many disinfection options, and its antimicrobial properties will help kill trapped bacteria and viruses, say the researchers. In addition, they are recyclable. The researchers estimate that the materials would cost around $2 per mask at present, and disinfection and reuse would extend their lifetime, making them economically competitive with current products.

The authors acknowledge funding from the Georgetown Environmental Initiative Impact Program Award, the McDevitt bequest to Georgetown University and Tom and Ginny Cahill's Fund for Environmental Physics at University of California Davis.

Nature produces a startling array of patterned materials, from the sensitive ridges on a person's fingertip to a cheetah's camouflaging spots. Although nature's patterns arise spontaneously during development, creating patterns on synthetic materials is more laborious. Now, researchers reporting in ACS Central Science have found an easy way to make patterned materials having complex microstructures with variations in mechanical, thermal and optical properties -- without the need for masks, molds or printers.

In animals, patterns form before birth in response to genetically controlled signals that often vary in concentration along a gradient. In contrast, traditional manufacturing approaches for creating patterns and structures involve multiple steps, such as layer-by-layer assembly, lithography, molding or casting. Jeffrey Moore, Nancy Sottos, Philippe Geubelle and colleagues wanted to develop a spontaneous patterning method more akin to the biological process.

The team placed a solution of dicyclopentadiene monomer in a channel and then heated one end of the channel. The heat activated a ruthenium catalyst, which caused the monomer to polymerize, generating more heat that traveled down the channel. This continued to happen until all available monomer in the region was consumed. Eventually, heat traveled farther down the channel to a location where fresh monomer was present, and the process began again. With this technique, the team produced resins with regular ridges, and they controlled the height and spacing of the ridges by adjusting the initial temperature of the solution. By using a different monomer or adding other compounds to the solution, the researchers created materials with patterns of color and stiffness. The new method could someday be used to create a variety of new "smart" materials, from tire or shoe treads to electronics and biomaterials, the researchers say.

80% of jobs are communicated to people informally and these communications are often riddled with gender bias, providing a female (versus male) candidate with a less positive description of a leadership position, especially when the decision maker is more conservative. These are the findings of a new study by Ekaterina Netchaeva, of Bocconi University's Department of Management and Technology, looking at the role gender bias may play in the leadership gap between men and women.

The persistence of a gender wage gap indicates that while discrimination is ending, bias lingers. The World Economic Forum's Global Gender Gap Report 2020 found "there is still a 31.4% average gender gap that remains to be closed globally." With this in mind, Prof. Netchaeva teamed up with two colleagues on a research project to look at the role gender bias may play in the leadership gap. In the private sector, women occupy only 29% of senior-level executive positions despite comprising 48% of the entire private sector workforce. "We wanted to understand if perhaps women were subtly discouraged from pursuing leadership positions," Netchaeva explains.

Netchaeva, Maryam Kouchaki (Kellogg School of Management) and Burak Oc (Melbourne Business School) carried out five experimental studies to detect possible gender bias in communication during the pre-recruitment phase. The group honed in on political ideology as a predictor of bias, "because this individual characteristic predicts favoring of status quo," as they say in their paper "It's a man's world! the role of political ideology in the early stages of leader recruitment," published on Organizational Behavior and Human Decision Processes.

Participants were told they had to recruit a male and female leader for an imaginary company, and were given eight pieces of information about the company. They were randomly split into two groups, and one had to communicate with the female candidate (Sarah) and the other with the male candidate (David). Conservative participants in the group that thought they were communicating with David picked more positive pieces of information about the position and the company, and those communicating with Sarah picked less positive information. The result was the same when recruiters were asked to write their own email describing the position.

Conservative participants were less positive in describing the position to the female candidate, and more positive when they thought they were talking with David - probably because conservatives tend to favor the status quo (male leadership, in this case). Liberals, instead, did not exhibit this trend.

"Given the statistics that 80% of jobs are communicated to people informally, and coupled with our finding that these communications may be riddled with gender bias, it is important for companies to rethink about how they communicate with candidates at that stage. One way to do that would be to make the process more formalized to allow for less gender bias and less human error," said Netchaeva.

The study, building on cooperation between climate scientists from the MENA region, aimed at assessing emerging heatwave characteristics. The research team used a first-of-its-kind multi-model ensemble of climate projections designed exclusively for the geographic area. Such detailed downscaling studies had been lacking for this region. The researchers then projected future hot spells and characterised them with the Heat Wave Magnitude Index. The good match among the model results and with observations indicates a high level of confidence in the heat wave projections.

"Our results for a business-as-usual pathway indicate that especially in the second half of this century unprecedented super- and ultra-extreme heatwaves will emerge", explains George Zittis of The Cyprus Institute, first author of the study. These events will involve excessively high temperatures of up to 56 degrees Celsius and higher in urban settings and could last for multiple weeks, being potentially life-threatening for humans and animals. In the second half of the century, about half of the MENA population or approximately 600 million people could be exposed to such annually recurring extreme weather conditions.

"Vulnerable citizens may not have the means to adapt to such harsh environmental conditions", adds Jos Lelieveld, Director at the Max Planck Institute for Chemistry and leading the research team. "These heat waves combined with regional economic, political, social and demographic drivers have a high potential to cause massive, forced migration to cooler regions in the north."

To avoid such extreme heat events in the region, the scientists recommend immediate and effective climate change mitigation measures. "Such measures include drastic decreases of the emissions of greenhouse gases such as carbon dioxide and methane into the atmosphere, but also adaptation solutions for the cities in the area", says Lelieveld. It is expected that in the next 50 years, almost 90 percent of the exposed population in the MENA will live in urban centers, which will need to cope with these societally disruptive weather conditions. "There is an urgent need to make the cities more resilient to climate change", emphasizes Zittis.

March 24, 2021 -- Perhaps the most frustrating limitation of owning an all-electric car is how long it takes to fully charge the battery. For a Tesla, for example, it takes about 40 minutes to charge it to 80% capacity using the most powerful charging station.

Scientists have long thought the laws of physics limited how fast you could safely recharge a battery, but new research by University of Utah chemical engineering assistant professor Tao Gao has opened the door to creating a battery that can be recharged in just a fraction of the time.

Gao's research was detailed in a new paper published in the scientific journal Joule. The study was conducted while Gao was a postdoctoral researcher at the Massachusetts Institute of Technology under the supervision of MIT chemical engineering professor Martin Z. Bazant. Gao is now carrying on that research at the University of Utah where he is further developing advanced lithium-ion batteries capable of fast charging.

"This understanding lays the foundation for the future engineering work needed to address this challenge," says Gao. "Now we know where to go. We have a clear vision of what needs to be done."

Lithium-ion batteries have become a popular choice for portable electronics and all-electric vehicles because of their high energy density, low weight and long life. They are also used in laptop computers, portable electric appliances and for solar energy storage.

But how quickly a lithium-ion battery can recharge is hampered by a phenomenon known as "lithium plating," a side reaction that happens when lithium ions are put into graphite particles too fast. Gao compares the operation of a lithium-ion battery to a ping pong ball being batted back and forth on a table. The ball, or lithium ion, travels from the positive electrode to the negative electrode during the charging process. The charging rate is similar to how fast the ball travels. Lithium plating occurs when the lithium ion moves too fast and the graphite particles in the battery fails to catch it, Gao explains. While charging, this can be hazardous and cause the battery to catch fire or explode, so that limits how quickly batteries can be recharged. It also can seriously degrade the battery, limiting its life.

Gao's discovery reveals the important physics that govern the lithium plating phenomena in graphite particles during battery charging and enables the prediction of lithium plating in the operation of a battery.

"We designed an experiment that can visualize what happens to the negative electrode during charging. We can see the graphite particle - the material in the negative electrode - and we can see what happens during battery charging in real time," he says. "Now we understand the physics. This provides us direction to address this limitation and improve battery charging performance."

Gao believes that with this fresh understanding, new technologies could create a car battery that could be fully charged five times faster than normal, or in just over 10 minutes, without the risk of a hazard or degrading too quickly, he says. Smartphones, which typically take more than a half an hour with the fastest charger, could also be fully charged in just 10 minutes, he says.

Now that Gao and his co-researchers have a better grasp of the science behind lithium-ion charging, he believes we could see cell phones with better batteries in as little as three to five years and on all-electric cars in as soon as five to 10 years.

Honeybees play a scent-driven game of telephone to guide members of a colony back to their queen, according to a new study led by University of Colorado Boulder. The research, published today in the Proceedings of the National Academy of Sciences, highlights how insects with limited cognitive abilities can achieve complex feats when they work together--even creating what looks like a miniature and buzzing version of a telecommunications network.

The findings also serve as a testament to a honeybee's love for its queen. These matriarchs are the most important members of any hive: They're the only females able to reproduce. Queens, like other members of a colony, can also communicate using pheromones, or small and odorous molecules that bees produce through special glands.

"It's very important for the bees to know where the queen is and to stay close to her," said study author Orit Peleg, an assistant professor in the BioFrontiers Institute and Department of Computer Science at CU Boulder.

Pheromones, which are too small for scientists to observe directly, can only travel so far before they dissipate into the air.

So bees get creative to pass the messages along. Drawing on experiments with live bees and computer simulations, or models, Peleg and her colleagues discovered that when a queen starts sending out pheromones, nearby insects take note. They stop what they're doing, start making their own pheromones, then transmit those scents to friendly bees that are farther away.

Peleg added that the results could one day help engineers to design more efficient telecommunications networks--for humans.

"There are many examples of animals, like ants, who lay pheromones in their environments," Peleg said. "But those pheromones just disperse passively by the laws of physics. Here, the bees are actively directing that signal."

Shake it

That conclusion, she added, came about from a chance observation. During a previous study, Peleg and her colleagues were tracking how honeybees form giant swarms--or undulating blobs made up of thousands to as many as 100,000 bees.

In the process, the researchers spotted something strange. As the honeybees in their experiments gathered around a queen to build a swarm, large numbers of them began to engage in what scientists call the "scenting" behavior. They stuck their hind ends into the air and beat their wings furiously.

"When they fan their wings, they're drawing air over their pheromone glands, blowing those molecules away," Peleg said.

She and her team wanted to know what was behind this insect version of twerking.

To do that, the group set up a video camera in an arena and recorded bees in the process of forming a swarm. The researchers then analyzed that footage using machine learning tools that automatically tracked the locations and orientations of the bees in a colony.

The team discovered the bees didn't seem to spread their scent randomly.

"The signal is broadcasted in a particular direction, and that direction tends to be away from the queen," Peleg said.

Phoning home

Picture an insect phone tree: The bees closest to the queen catch whiff of her smell molecules, then blow their own pheromones to the bees behind them. That next layer of bees passes the message on in turn, and the chain continues until every bee in the colony is in on the secret.

"It almost resembles a telecommunications network where you have antennas that are talking to each other and amplifying the signal so that it can reach farther away," Peleg said.

Dieu My Nguyen, lead author of the study, noted that at the height of this communication frenzy, a hive's messenger bees mostly spaced themselves evenly across an arena.

"The distances between the scenting bees were very uniform," said Nguyen, a graduate student in computer science at CU Boulder. "That suggests that there is some sort of concentration threshold over which pheromones are detectable, and that the bees were responding to that."

Peleg, Nguyen, and their colleagues say that there is still a lot that they don't know about how these communications networks work. Do only some bees, for example, transmit messages for the queen, or can all members of a hive sniff and fan when it suits them? For now, the team is happy to get a new whiff of the social lives of these curious insects.

"We got a few bee stings," Nguyen said. "But it was worth it for those nice movies."

Osaka, Japan - Scientists from the Division of Sustainable Energy and Environmental Engineering at Osaka University employed deep learning artificial intelligence to improve mobile mixed reality generation. They found that occluding objects recognized by the algorithm could be dynamically removed using a video game engine. This work may lead to a revolution in green architecture and city revitalization.

Mixed reality (MR) is a type of visual augmentation in which real-time images of existing objects or landscapes can be digitally altered. As anyone who has played Pokémon Go! or similar games knows, looking at a smartphone screen can feel almost like magic when characters appear alongside real landmarks. This approach can be applied for more serious undertakings as well, such as visualizing what a new building will look like once the existing structure is removed and trees added. However, this kind of digital erasure was thought to be too computationally intensive to generate in real time on a mobile device.

Now, researchers at Osaka University have demonstrated a new system that can construct a MR landscape visualization faster with the help of deep learning. The key is to train the algorithm with thousands of labeled images so that it can more quickly identify occlusions, like walls and fences. This allows for the automatic "semantic segmentation" of the view into elements to be kept and others to be masked. The program also quantitatively measured the Green View Index (GVI), which is the fraction of greenery areas including plants and trees in a person's visual field, in either the current or proposed layout. "We were able to implement both dynamic occlusion and Green View Index estimation in our mixed reality viewer," corresponding author Tomohiro Fukuda says.

Live video is sent to a semantic segmentation server, and the result is used to render the final view with a game engine on the mobile device. Proposed structures and greenery can be shown even when the viewing angle is changed. "Internet speed and latency were evaluated to ensure real-time MR rendering," first author Daiki Kido explains. The team hopes this research will help stakeholders understand the importance of GVI on urban planning.

Materials science likes to take nature and the special properties of living beings that could potentially be transferred to materials as a model. A research team led by chemist Professor Andreas Walther of Johannes Gutenberg University Mainz (JGU) has succeeded in endowing materials with a bioinspired property: Wafer-thin stiff nanopaper instantly becomes soft and elastic at the push of a button. "We have equipped the material with a mechanism so that the strength and stiffness can be modulated via an electrical switch," explained Walther. As soon as an electric current is applied, the nanopaper becomes soft; when the current flow stops, it regains its strength. From an application perspective, this switchability could be interesting for damping materials, for example. The work, which also involved scientists from the University of Freiburg and the Cluster of Excellence on "Living, Adaptive, and Energy-autonomous Materials Systems" (livMatS) funded by the German Research Foundation (DFG), was published in Nature Communications.

Inspiration from the seafloor: Mechanical switch serves a protective function

The nature-based inspiration in this case comes from sea cucumbers. These marine creatures have a special defense mechanism: When they are attacked by predators in their habitat on the seafloor, sea cucumbers can adapt and strengthen their tissue so that their soft exterior immediately stiffens. "This is an adaptive mechanical behavior that is fundamentally difficult to replicate," said Professor Andreas Walther. With their work now published, his team has succeeded in mimicking the basic principle in a modified form using an attractive material and an equally attractive switching mechanism.

The scientists used cellulose nanofibrils extracted and processed from the cell wall of trees. Nanofibrils are even finer than the microfibers in standard paper and result in a completely transparent, almost glass-like paper. The material is stiff and strong, appealing for lightweight construction. Its characteristics are even comparable to those of aluminum alloys. In their work, the research team applied electricity to these cellulose nanofibril-based nanopapers. By means of specially designed molecular changes, the material becomes flexible as a result. The process is reversible and can be controlled by an on/off switch.

"This is extraordinary. All the materials around us are not very changeable, they do not easily switch from stiff to elastic and vice versa. Here, with the help of electricity, we can do that in a simple and elegant way," said Walther. The development is thus moving away from classic static materials toward materials with properties that can be adaptively adjusted. This is relevant for mechanical materials, which can thus be made more resistant to fracture, or for adaptive damping materials, which could switch from stiff to compliant when overloaded, for example.

Targeting a material with its own energy storage for autonomous on/off switching

At the molecular level, the process involves heating the material by applying a current and thus reversibly breaking cross-linking points. The material softens in correlation with the applied voltage, i.e., the higher the voltage, the more cross-linking points are broken and the softer the material becomes. Professor Andreas Walther's vision for the future also starts at the point of power supply: While currently a power source is needed to start the reaction, the next goal would be to produce a material with its own energy storage system, so that the reaction is essentially triggered "internally" as soon as, for example, an overload occurs and damping becomes necessary. "Now we still have to flip the switch ourselves, but our dream would be for the material system to be able to accomplish this on its own."

SMN or in full Survival Motor Neuron: Professor Utz Fischer has been analyzing this protein and the large molecular complex of the same name, of which SMN is one of the building blocks, for many years. He holds the Chair of the Department of Biochemistry at the Julius-Maximilian's University of Würzburg (JMU), and he first discovered the molecule during his search for the root cause of spinal muscular atrophy. As scientists found out a few years ago, this disease is caused by a lack of the SNM complex.

The work group around Prof. Fischer has now succeeded in presenting a first three-dimensional model of the entire SNM complex. Once the structure of the complex is known, it is possible to understand the way how the complex works, and why the loss of its function leads to muscular atrophy. The scientists have published their findings in the current issue of the journal Nucleic Acids Research. The journal considers it to the a "Breakthrough Article".

The new findings have been made possible by an integrative structural-biological approach that combines biochemical, genetic and biophysical technologies.

Resolution up to a millionth of a millimeter

"The structural analysis of large and complex molecules in atomic detail has been made possible by the 'revolution-resolution', which was primarily brought about by the developments in cryo-electron microscopy", says Utz Fischer. The only snag about the technology, however, is the fact that it works best on structures that are more or less rigid and have few flexible sections.

Unfortunately, many molecular entities are not built like this, including the SMN complex. "This complex is of central importance for our cells because it supports the formation of molecular machines required for the expression of our genes", says Prof. Fischer. However, in order to serve its function in the cell, it must be highly flexible and dynamic. As a result, a structural analysis by traditional strategies has been impossible so far.

A combination of different methods was the key to success

Therefore the Fischer and his team chose an alternative approach: "Our starting point was a cooperation with the group of Dr. Rémy Bordonné from Montpellier in France, that enabled us to identify the SMN complex of the yeast Schizosaccharomyces pombe", he explains. This complex was ideally suited for an integrative structural analysis because it comprises less individual components than its human counterpart and has a less dynamic behavior.

"In a first step, we visualized, by X-ray diffraction analysis, individual sections that are important for keeping the complex together", says Fischer about the scientists' approach. In a second step, they characterized the entire complex and parts of it by means of small-angle X-ray scattering. This method also provides information on the dynamic behavior of unfolded sections of the complex. In parallel, missing sections were reconstructed by means of a bioinformatic method called 3D homology modeling.

This combination of different structural-biological methods will gain in importance in the future because it produces results that have never been achieved before - such is the conviction of Dr. Clemens Grimm. He is the Head of the "Structural Analysis" unit of Fischer's department, and has contributed to the recently published work.

An octopus with flexible arms

The result was a model of the entire SMN complex that provides an excellent explanation of its function. Similar as in an octopus, the central "body" of the complex has a number of long and very flexible "arms", which enable the complex to catch proteins and assemble them, together with other biomolecules, into molecular machines.

The model also provides insight into the processes that lead to spinal muscular atrophy. "The mutations causing this disease concentrate in the central body" explains Fischer's doctoral student Jyotishman Veepaschit, who performed experiments of this study together with his colleague Aravindan Viswanathan. They prevent the full development of the complex, so that it cannot serve its function in the cell.