But a breakthrough by researchers in Drexel’s College of Engineering, could now make installing an antenna as easy as applying some bug spray.

In research recently published in Science Advances, the group reports on a method for spraying invisibly thin antennas, made from a type of two-dimensional, metallic material called MXene, that perform as well as those being used in mobile devices, wireless routers and portable transducers.

“This is a very exciting finding because there is a lot of potential for this type of technology,” said Kapil Dandekar, PhD, a professor of Electrical and Computer Engineering in the College of Engineering, who directs the Drexel Wireless Systems Lab, and was a co-author of the research. “The ability to spray an antenna on a flexible substrate or make it optically transparent means that we could have a lot of new places to set up networks — there are new applications and new ways of collecting data that we can’t even imagine at the moment.”

The researchers, from the College’s Department of Materials Science and Engineering, report that the MXene titanium carbide can be dissolved in water to create an ink or paint. The exceptional conductivity of the material enables it to transmit and direct radio waves, even when it’s applied in a very thin coating.

“We found that even transparent antennas with thicknesses of tens of nanometers were able to communicate efficiently,” said Asia Sarycheva, a doctoral candidate in the A.J. Drexel Nanomaterials Institute and Materials Science and Engineering Department. “By increasing the thickness up to 8 microns, the performance of MXene antenna achieved 98 percent of its predicted maximum value.”

Preserving transmission quality in a form this thin is significant because it would allow antennas to easily be embedded — literally, sprayed on — in a wide variety of objects and surfaces without adding additional weight or circuitry or requiring a certain level of rigidity.

“This technology could enable the truly seamless integration of antennas with everyday objects which will be critical for the emerging Internet of Things,” Dandekar said. “Researchers have done a lot of work with non-traditional materials trying to figure out where manufacturing technology meets system needs, but this technology could make it a lot easier to answer some of the difficult questions we’ve been working on for years.”

Initial testing of the sprayed antennas suggest that they can perform with the same range of quality as current antennas, which are made from familiar metals, like gold, silver, copper and aluminum, but are much thicker than MXene antennas. Making antennas smaller and lighter has long been a goal of materials scientists and electrical engineers, so this discovery is a sizeable step forward both in terms of reducing their footprint as well as broadening their application.

“Current fabrication methods of metals cannot make antennas thin enough and applicable to any surface, in spite of decades of research and development to improve the performance of metal antennas,” said Yury Gogotsi, PhD, Distinguished University and Bach professor of Materials Science and Engineering in the College of Engineering, and Director of the A.J. Drexel Nanomaterials Institute, who initiated and led the project. “We were looking for two-dimensional nanomaterials, which have sheet thickness about hundred thousand times thinner than a human hair; just a few atoms across, and can self-assemble into conductive films upon deposition on any surface. Therefore, we selected MXene, which is a two-dimensional titanium carbide material, that is stronger than metals and is metallically conductive, as a candidate for ultra-thin antennas.”

Drexel researchers discovered the family of MXene materials in 2011 and have been gaining an understanding of their properties, and considering their possible applications, ever since. The layered two-dimensional material, which is made by wet chemical processing, has already shown potential in energy storage devices, electromagnetic shielding, water filtration, chemical sensing, structural reinforcement and gas separation.

Naturally MXene materials have drawn comparisons to promising two-dimensional materials like graphene, which won the Nobel Prize in 2010 and has been explored as a material for printable antennas. In the paper, the Drexel researchers put the spray-on antennas up against a variety of antennas made from these new materials, including graphene, silver ink and carbon nanotubes. The MXene antennas were 50 times better than graphene and 300 times better than silver ink antennas in terms of preserving the quality of radio wave transmission.

“The MXene antenna not only outperformed the macro and micro world of metal antennas, we went beyond the performance of available nanomaterial antennas, while keeping the antenna thickness very low,” said Babak Anasori, PhD, a research assistant professor in A.J. Drexel Nanomaterials Institute. “The thinnest antenna was as thin as 62 nanometers — about thousand times thinner than a sheep of paper — and it was almost transparent. Unlike other nanomaterials fabrication methods, that requires additives, called binders, and extra steps of heating to sinter the nanoparticles together, we made antennas in a single step by airbrush spraying our water-based MXene ink.”

The group initially tested the spray-on application of the antenna ink on a rough substrate — cellulose paper — and a smooth one — polyethylene terephthalate sheets — the next step for their work will be looking at the best ways to apply it to a wide variety of surfaces from glass to yarn and skin.

“Further research on using materials from the MXene family in wireless communication may enable fully transparent electronics and greatly improved wearable devices that will support the active lifestyles we are living,” Anasori said.

The model, published in the journal PLoS One, combines existing data and models of four major factors: future climate change scenarios, ocean acidification impacts, fisheries management policies, and fuel costs for fishermen.

“What’s novel about our work is that it brings together models of changing ocean environments as well as human responses” says Jennie Rheuban, the lead author of the study. “It combines socioeconomic decision making, ocean chemistry, atmospheric carbon dioxide, economic development and fisheries management. We tried to create a holistic view of how environmental changes might play out across different aspects of the sea scallop fishery,” she notes.

Since the oceans can absorb more than a quarter of all excess carbon dioxide in the atmosphere, fossil fuel carbon emissions can cause a dip in ocean pH as well. That acidity can corrode the calcium carbonate shells that are made by shellfish like clams, oysters, and scallops, and even prevent their larvae from forming shells in the first place.

According to Rheuban, no existing studies have been published that can show the specific effects of ocean acidification on the Atlantic sea scallop. To estimate its impact in the model, she and her colleagues incorporated a range of effects based on studies of related shellfish species. Combined with estimates of changing water chemistry, this new model lets scientists explore how plausible impacts of ocean acidification may change the future of the scallop population.

Rheuban and colleagues tested four different levels of impact in each of the four different factors influencing the model, ultimately creating 256 different scenario combinations.One group of scenarios looks at possible pathways of how ocean acidification may impact scallop biology. Another examines different levels of atmospheric CO₂, including one future where emissions continue to skyrocket, and one where they fall due to aggressive climate change policy. A third set includes a range of future fuel costs, which themselves are related to climate change policies. Higher fuel costs, Rheuban notes, can lead to fewer active fishing days, reducing stress on the fishery itself, but also reducing profitability and revenues of the industry. The fourth and final set involves different federal fisheries management techniques.

Fishing policies for some shellfish, like oyster, clams, and bay scallops, are regulated by state or local governments, each of which follows its own set of rules. Sea scallop fisheries, however, are located well offshore in a region stretching from Virginia to Maine, so are regulated mostly by the federal government. With only one set of rules covering most sea scallop fisherman, it’s possible to fit them into the model.

“The current sea scallop fishery is so healthy and valuable today in part because it is very well managed,” says Scott Doney, a co-author from WHOI and the University of Virginia. “We also used the model to ask whether management approaches could offset the negative impacts of ocean acidification.”

In all of the model’s possible scenarios, high levels of CO₂ in the atmosphere consistently led to increased ocean acidification and fewer sea scallops, despite introducing stricter management rules or even closing part of the fishery entirely.

“The model highlights the potential risks to sea scallops and likely other commercial shellfish fisheries of unabated carbon emissions to the atmosphere” adds Doney.

Over the next 100 years, under the worst-case ocean acidification impacts, the model’s ‘business-as-usual’ scenario shows a sea scallop decline of more than 50%, while a scenario with proactive climate policy shows only a 13% reduction.

“The model shows that reductions in fossil fuel emissions due to climate policy might have a big impact on the sea scallop fishery,” concludes Rheuban.

Now a new MIT study reports that Volkswagen is not the only auto manufacturer to make diesel cars that produce vastly more emissions on the road than in laboratory tests. The study, published this month in Atmospheric Environment, finds that in Europe, 10 major auto manufacturers produced diesel cars, sold between 2000 and 2015, that generate up to 16 times more emissions on the road than in regulatory tests — a level that exceeds European limits but does not violate any EU laws.

What’s more, the researchers predict these excess emissions will have a significant health impact, causing approximately 2,700 premature deaths per year across Europe. These health effects, they found, are “transboundary,” meaning that diesel emissions produced in one country can adversely affect populations in other countries, thousands of kilometers away.

“You might imagine that where the excess emissions occur is where people might die early,” says study author Steven Barrett, the Raymond L. Bisplinghoff Professor of Aeronautics and Astronautics at MIT. “But instead we find that 70 percent of the total [health] impacts are transboundary. It suggests coordination is needed not at the country, but at the continental scale, to try to solve this problem of excess emissions.”

The 10 manufacturers’ excess emissions may not be a result of unlawful violations, as was the case with Volkswagen. Instead, the team writes that “permissive testing procedures at the EU level and defective emissions control strategies” may be to blame.

The researchers report a silver lining: If all 10 auto manufacturers were to improve their emissions control technologies to perform at the same level as the best manufacturer in the group, this would prevent up to 1,900 premature deaths per year.

“That’s pretty significant in terms of the number of premature mortalities that would be avoided,” Barrett says.

Barrett’s co-authors at MIT are Guillaume Chossière, Robert Malina (now at Hasselt University), Florian Allroggen, Sebastian Eastham, and Raymond Speth.

Tuning the knobs

The study focuses on emissions of nitrogen oxides, or NOx, a type of gas that is produced in diesel exhaust. When the gas gets oxidized and reacts with ammonia in the atmosphere, it forms fine particles and can travel for long distances before settling. When these particles are inhaled, they can lodge deep in the lungs, causing respiratory disease, asthma, and other pulmonary and cardiac conditions. Additionally NOx emissions cause the formation of ozone, a pollutant long associated with adverse health outcomes.

“There are many times the number of diesel cars in Europe compared to the U.S., partly because the EU started pushing diesel for environmental reasons, as it produces less carbon dioxide emissions compared with [gasoline],” Barrett says. “It’s a case where diesel has probably been beneficial in terms of climate impacts, but it’s come at the cost of human health.”

Recently, the EU started tightening its standards for diesel exhaust to reduce NOx emissions and their associated health effects. However, independent investigations have found that most diesel cars on the road do not meet the new emissions standards in real driving conditions.

“Initially manufacturers were able to genuinely meet regulations, but more recently it seems they’ve almost tweaked knobs to meet the regulations on paper, even if in reality that’s not reproduced on the road,” Barrett says. “And that’s not been illegal in Europe.”

Life exposure

In this study, Barrett and his colleagues quantified the health impacts in Europe of excess NOx emissions — emissions that were not accounted for in standard vehicle testing but are produced in actual driving conditions. They also estimated specific manufacturers’ contributions to the total health impacts related to the excess emissions.

The researchers considered 10 major auto manufacturers of diesel cars sold in Europe, for which lab and on-road emissions data were available: Volkswagen, Renault, Peugeot-Citroën, Fiat, Ford, General Motors, BMW, Daimler, Toyota, and Hyundai. Together, these groups represent more than 90 percent of the total number of diesel cars sold between 2000 and 2015, in 28 member states of the EU, along with Norway and Switzerland.

For each manufacturer, the team calculated the total amount of excess emissions produced by that manufacturer’s diesel car models, based on available emissions data from laboratory testing and independent on-road tests. They found that overall, diesel cars produce up to 16 times more NOx emissions on the road than in lab tests.

They then calculated the excess emissions associated with each manufacturer’s diesel car, by accounting for the number of those cars that were sold between 2000 and 2015, for each country in which those cars were sold.

The team used GEOS-Chem, a chemistry transport model that simulates the circulation of chemicals and particles through the atmosphere, to track where each manufacturer’s excess NOx emissions traveled over time. They then overlaid a population map of the EU onto the atmospheric model to identify specific populations that were most at risk of exposure to the excess NOx emissions.

Finally, the team consulted epidemiological work to relate various populations’ NOx exposure to their estimated health risk. The researchers considered four main populations in these calculations: adults with ischemic heart disease, stroke, chronic obstructive pulmonary disease, and lung cancer.

Overall, they estimated that, each year, 2,700 people within these populations will lose at least a decade of their life due to exposure to excess NOx emissions from passenger cars. They broke this number down by manufacturer and found a wide spread of health impact contributions: Volkswagen, Renault, and General Motors produced diesel cars associated with the most yearly premature deaths, each numbering in the hundreds, while Toyota, Hyundai, and BMW were associated with fewer early deaths.

“The variation across manufacturers was more than a factor of five, which was much bigger than we expected,” Barrett says.

“There’s no safe level”

For each country, the team also compared the excess emissions that it produced itself, versus the number of premature deaths that its population incurred, and found virtually no relationship. That is, some countries, such as Poland and Switzerland, produced very little NOx emissions and yet experienced a disproportionate number of premature deaths from excess emissions originating in other countries.

Barrett says this transboundary effect may be due to the nature of NOx emissions. Unlike particulate matter spewed from smokestacks, such as soot, which mostly settles out in the local area, NOx is first emitted as a gas, which can be carried easily by the wind across thousands of kilometers, before reacting with ammonia to form particulates, a form of the chemical that can ultimately cause respiratory and cardiac problems.

“There’s almost no correlation between who drives [diesel cars] and who incurs the health disbenefits, because the impacts are so diffuse through all of Europe,” Barrett says.

The study ends with a final result: If all 10 manufacturers were to meet the on-road emissions performance of the best manufacturer in the group, this would avoid 1,900 premature deaths due to NOx exposure. But Barrett says ultimately, regulators and manufacturers will have to go even further to prevent emissions-associated mortalities.

“The solution is to eliminate NOx altogether,” Barrett says. “We know there are human health impacts right down to pre-industrial levels, so there’s no safe level. At this point in time, it’s not that we have to go back to [gasoline]. It’s more that electricification is the answer, and ultimately we do have to have zero emissions in cities.”

While still based on early-stage research and far from commercial deployment, the new battery formulation could open up new avenues for tailoring electrochemical carbon dioxide conversion reactions, which may ultimately help reduce the emission of the greenhouse gas to the atmosphere.

The battery is made from lithium metal, carbon, and an electrolyte that the researchers designed. The findings are described today in the journal Joule, in a paper by assistant professor of mechanical engineering Betar Gallant, doctoral student Aliza Khurram, and postdoc Mingfu He.

Currently, power plants equipped with carbon capture systems generally use up to 30 percent of the electricity they generate just to power the capture, release, and storage of carbon dioxide. Anything that can reduce the cost of that capture process, or that can result in an end product that has value, could significantly change the economics of such systems, the researchers say.

However, “carbon dioxide is not very reactive,” Gallant explains, so “trying to find new reaction pathways is important.” Generally, the only way to get carbon dioxide to exhibit significant activity under electrochemical conditions is with large energy inputs in the form of high voltages, which can be an expensive and inefficient process. Ideally, the gas would undergo reactions that produce something worthwhile, such as a useful chemical or a fuel. However, efforts at electrochemical conversion, usually conducted in water, remain hindered by high energy inputs and poor selectivity of the chemicals produced.

Gallant and her co-workers, whose expertise has to do with nonaqueous (not water-based) electrochemical reactions such as those that underlie lithium-based batteries, looked into whether carbon-dioxide-capture chemistry could be put to use to make carbon-dioxide-loaded electrolytes — one of the three essential parts of a battery — where the captured gas could then be used during the discharge of the battery to provide a power output.

This approach is different from releasing the carbon dioxide back to the gas phase for long-term storage, as is now used in carbon capture and sequestration, or CCS. That field generally looks at ways of capturing carbon dioxide from a power plant through a chemical absorption process and then either storing it in underground formations or chemically altering it into a fuel or a chemical feedstock.

Instead, this team developed a new approach that could potentially be used right in the power plant waste stream to make material for one of the main components of a battery.

While interest has grown recently in the development of lithium-carbon-dioxide batteries, which use the gas as a reactant during discharge, the low reactivity of carbon dioxide has typically required the use of metal catalysts. Not only are these expensive, but their function remains poorly understood, and reactions are difficult to control.

By incorporating the gas in a liquid state, however, Gallant and her co-workers found a way to achieve electrochemical carbon dioxide conversion using only a carbon electrode. The key is to preactivate the carbon dioxide by incorporating it into an amine solution.

“What we’ve shown for the first time is that this technique activates the carbon dioxide for more facile electrochemistry,” Gallant says. “These two chemistries — aqueous amines and nonaqueous battery electrolytes — are not normally used together, but we found that their combination imparts new and interesting behaviors that can increase the discharge voltage and allow for sustained conversion of carbon dioxide.”

They showed through a series of experiments that this approach does work, and can produce a lithium-carbon dioxide battery with voltage and capacity that are competitive with that of state-of-the-art lithium-gas batteries. Moreover, the amine acts as a molecular promoter that is not consumed in the reaction.

The key was developing the right electrolyte system, Khurram explains. In this initial proof-of-concept study, they decided to use a nonaqueous electrolyte because it would limit the available reaction pathways and therefore make it easier to characterize the reaction and determine its viability. The amine material they chose is currently used for CCS applications, but had not previously been applied to batteries.

This early system has not yet been optimized and will require further development, the researchers say. For one thing, the cycle life of the battery is limited to 10 charge-discharge cycles, so more research is needed to improve rechargeability and prevent degradation of the cell components. “Lithium-carbon dioxide batteries are years away” as a viable product, Gallant says, as this research covers just one of several needed advances to make them practical.

But the concept offers great potential, according to Gallant. Carbon capture is widely considered essential to meeting worldwide goals for reducing greenhouse gas emissions, but there are not yet proven, long-term ways of disposing of or using all the resulting carbon dioxide. Underground geological disposal is still the leading contender, but this approach remains somewhat unproven and may be limited in how much it can accommodate. It also requires extra energy for drilling and pumping.

The researchers are also investigating the possibility of developing a continuous-operation version of the process, which would use a steady stream of carbon dioxide under pressure with the amine material, rather than a preloaded supply the material, thus allowing it to deliver a steady power output as long as the battery is supplied with carbon dioxide. Ultimately, they hope to make this into an integrated system that will carry out both the capture of carbon dioxide from a power plant’s emissions stream, and its conversion into an electrochemical material that could then be used in batteries. “It’s one way to sequester it as a useful product,” Gallant says.

Light pollution can have many influences on ecological processes. Previous research has shown that artificial light at night can have several direct consequences on night-time activity and movement patterns of animals. Many animal species, for example birds and insects, are attracted by artificial light sources at night and can, as a result, loose their orientation. But how artificial light at night impacts the behaviour of individuals during the day, when the source of light pollution is absent, is largely unknown.

In this study, a team led by Ralf Kurvers of the MPI for Human Development in collaboration with the IGB, tested how exposure to artificial light at night affected the behaviour of fish during the day. As study species, they used guppies, a tropical freshwater fish and one of the model organisms of animal behavioural science. The scientists studied three groups of animals. Each group was exposed to the same bright light conditions during the day, but to different illuminations during the night. The first group experienced complete darkness at night; the second group was kept at a low light level at night, comparable to nocturnal illuminance under a street lamp; and the third group experienced bright light at night. After ten weeks of exposure, the scientists conducted behavioural tests to study the consequences of nightly light exposure on daytime behaviours.

The results: Fish left their hiding places faster during the day and swam more often in the riskier, open areas of the aquarium when exposed to strong, but also weak, artificial light at night. The light exposed fish thus increased their willingness to take risks. “The consequences of this increased risk taking behaviour are difficult to predict, but it is possible that they could be more at risk of predation by birds or other fish” says IGB researcher David Bierbach, co-author of the study. The light exposed fish did not differ in swimming speed and sociality, as compared to the control fish. “We suspect that the nocturnal light causes a stress response in the fish, and fish generally increase their risk taking when experiencing stress,” explains Ralf Kurvers, lead author of the study. Also in humans, a disruption of the night can cause a stress response. For example, firefighters who slept fewer hours during the night had elevated levels of the stress hormone cortisol.

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Optical illusions can be fun to experience and debate, but understanding how human brains perceive these different phenomena remains an active area of scientific research. For one class of optical illusions, called contextual phenomena, those perceptions are known to depend on context. For example, the color you think a central circle is depends on the color of the surrounding ring. Sometimes the outer color makes the inner color appear more similar, such as a neighboring green ring making a blue ring appear turquoise — but sometimes the outer color makes the inner color appear less similar, such as a pink ring making a grey circle appear greenish.

A team of Brown University computer vision experts went back to square one to understand the neural mechanisms of these contextual phenomena. Their study was published on Sept. 20 in Psychological Review.

“There’s growing consensus that optical illusions are not a bug but a feature,” said Thomas Serre, an associate professor of cognitive, linguistic and psychological sciences at Brown and the paper’s senior author. “I think they’re a feature. They may represent edge cases for our visual system, but our vision is so powerful in day-to-day life and in recognizing objects.”

For the study, the team lead by Serre, who is affiliated with Brown’s Carney Institute for Brain Science, started with a computational model constrained by anatomical and neurophysiological data of the visual cortex. The model aimed to capture how neighboring cortical neurons send messages to each other and adjust one another’s responses when presented with complex stimuli such as contextual optical illusions.

One innovation the team included in their model was a specific pattern of hypothesized feedback connections between neurons, said Serre. These feedback connections are able to increase or decrease — excite or inhibit — the response of a central neuron, depending on the visual context.

These feedback connections are not present in most deep learning algorithms. Deep learning is a powerful kind of artificial intelligence that is able to learn complex patterns in data, such as recognizing images and parsing normal speech, and depends on multiple layers of artificial neural networks working together. However, most deep learning algorithms only include feedforward connections between layers, not Serre’s innovative feedback connections between neurons within a layer.

Once the model was constructed, the team presented it a variety of context-dependent illusions. The researchers “tuned” the strength of the feedback excitatory or inhibitory connections so that model neurons responded in a way consistent with neurophysiology data from the primate visual cortex.

Then they tested the model on a variety of contextual illusions and again found the model perceived the illusions like humans.

In order to test if they made the model needlessly complex, they lesioned the model — selectively removing some of the connections. When the model was missing some of the connections, the data didn’t match the human perception data as accurately.

“Our model is the simplest model that is both necessary and sufficient to explain the behavior of the visual cortex in regard to contextual illusions,” Serre said. “This was really textbook computational neuroscience work — we started with a model to explain neurophysiology data and ended with predictions for human psychophysics data.”

In addition to providing a unifying explanation for how humans see a class of optical illusions, Serre is building on this model with the goal of improving artificial vision.

State-of-the-art artificial vision algorithms, such as those used to tag faces or recognize stop signs, have trouble seeing context, he noted. By including horizontal connections tuned by context-dependent optical illusions, he hopes to address this weakness.

Perhaps visual deep learning programs that take context into account will be harder to fool. A certain sticker, when stuck on a stop sign can trick an artificial vision system into thinking it is a 65-mile-per-hour speed limit sign, which is dangerous, Serre said.

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About three billion people around the world live in households that regularly burn wood, coal or other solid fuels to cook their food. Solid fuels emit very high levels of pollutants, especially very small particles that can penetrate deep into the lungs. Typically, these households are found in the rural areas of low- and middle-income countries. Although China is rapidly urbanizing, one third of its population still relies on solid fuels.

In “Solid Fuel Use and Risks of Respiratory Diseases: A Cohort Study of 280,000 Chinese Never-Smokers,” researchers from the Oxford University in the United Kingdom and the Chinese Academy of Medical Sciences report that chronic and acute respiratory disease hospitalizations or deaths were 36 percent higher among those who used wood or coal for cooking compared to those who used electricity or gas.

The researchers also report that the longer people used solid fuels, the higher the risk of hospitalization or death from a respiratory disease than those who cooked with gas or electricity. Those who used wood or coal for 40 years or longer, had a 54 percent higher risk of hospitalization or death from respiratory disease, while those who switched from solid fuels to clean-burning fuels reduced their risk to only 14 percent higher than those who never cooked with wood or coal.

The researchers adjusted their findings to account for age, sex, socio-economic status, passive smoking, alcohol drinking, diet, physical activity and obesity.

The study reviewed the health records of 280,000 adults, age 30 to 79, in the China Kadoorie Biobank (CKB). The participants were from 10 areas of the country, had never smoked and were free of respiratory and other major chronic diseases when they enrolled in the study. They were followed for nine years. During that time, 19,823 were either hospitalized or died from a major respiratory disease. Of these events, 10,553 were due to asthma or chronic obstructive pulmonary disease (COPD), and 7,324 were due to acute lower respiratory infections, most often pneumonia.

“While many previous studies have suggested a link between solid fuel use and COPD, most of them focused on changes in lung function, rather than hospital admissions or deaths,” said lead author Ka Hung Chan, MSc, a doctoral student at the University of Oxford’s Nuffield Department of Population Health. “In addition, we looked at the associations with other respiratory diseases about which little is known.”

Compared to other studies that have found a two- to three-fold increase in COPD among those burning wood or coal in their cookstoves, the authors noted that their research found a weaker association between burning wood or coal in a cookstove and COPD.

Kin Bong Hubert Lam, PhD, an associate professor at Oxford University who co-led this study, said several factors may explain this, including the fact that COPD is underdiagnosed in China, particularly in rural areas, where spirometry, an essential diagnostic tool in COPD, is rarely available. The weaker association found in their study “could also be due to concurrent exposure to wood or coal smoke among clean fuel users that our study was unable to measure, especially among those who lived in communities where solid fuel use is common,” he added.

According to Zhengming Chen, MBBS, DPhil, senior author and professor of epidemiology at the Nuffield Department of Population Health, the study’s most important finding may be that the increased risk of major respiratory diseases posed by burning wood or coal can be significantly lowered by switching to a clean-burning fuel.

“Although we cannot infer a causal relationship from these observational findings, our findings make a compelling case to speed up the global implementation of universal access to affordable clean energy, one of the United Nations Sustainable Development Goals,” he said.

A KAIST research team has reported a stretchable pressure insensitive strain sensor by using an all solution-based process. The solution-based process is easily scalable to accommodate for large areas and can be coated as a thin-film on 3-dimensional irregularly shaped objects via spray coating. These conditions make their processing technique unique and highly suitable for robotic electronic skin or wearable electronic applications.

The making of electronic skin to mimic the tactile sensing properties of human skin is an active area of research for various applications such as wearable electronics, robotics, and prosthetics. One of the major challenges in electronic skin research is differentiating various external stimuli, particularly between strain and pressure. Another issue is uniformly depositing electrical skin on 3-dimensional irregularly shaped objects.

To overcome these issues, the research team led by Professor Steve Park from the Department of Materials Science and Engineering and Professor Jung Kim from the Department of Mechanical Engineering developed electronic skin that can be uniformly coated on 3-dimensional surfaces and distinguish mechanical stimuli. The new electronic skin can also distinguish mechanical stimuli analogous to human skin.

The structure of the electronic skin was designed to respond differently under applied pressure and strain. Under applied strain, conducting pathways undergo significant conformational changes, considerably changing the resistance. On the other hand, under applied pressure, negligible conformational change in the conducting pathway occurs; e-skin is therefore non-responsive to pressure. The research team is currently working on strain insensitive pressure sensors to use with the developed strain sensors.

The research team also spatially mapped the local strain without the use of patterned electrode arrays utilizing electrical impedance tomography (EIT). By using EIT, it is possible to minimize the number of electrodes, increase durability, and enable facile fabrication onto 3-dimensional surfaces.

Professor Park said, “Our electronic skin can be mass produced at a low cost and can easily be coated onto complex 3-dimensional surfaces. It is a key technology that can bring us closer to the commercialization of electronic skin for various applications in the near future.”

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