Tech

The tree of life just got a little bigger: A team of scientists from the U.S. and China has identified an entirely new group of microbes quietly living in hot springs, geothermal systems and hydrothermal sediments around the world. The microbes appear to be playing an important role in the global carbon cycle by helping break down decaying plants without producing the greenhouse gas methane.

"Climate scientists should take these new microbes into account in their models to more accurately understand how they will impact climate change," said Brett Baker, assistant professor at The University of Texas at Austin's Marine Science Institute who led the research published April 23 in Nature Communications.

The new group, which biologists call a phylum, is named Brockarchaeota after Thomas Brock, a pioneer in the study of microbes that live in extreme environments such as the hot springs of Yellowstone National Park. Sadly, Brock died April 4. His research led to a powerful biotech tool called PCR, which is used, among other things, in gene sequencing and COVID-19 tests.

"The description of these new microbes from hot springs is a fitting tribute to Tom's legacy in microbiology," Baker added.

So far, Brockarchaeota have not been successfully grown in a laboratory or imaged under a microscope. Instead, they were identified by painstakingly reconstructing their genomes from bits of genetic material collected in samples from hot springs in China and hydrothermal sediments in the Gulf of California. Baker and the team used high-throughput DNA sequencing and innovative computational approaches to piece together the genomes of the newly described organisms. The scientists also identified genes that suggest how they consume nutrients, produce energy and generate waste.

"When we looked in public genetic databases, we saw that they had been collected all around the world but described as 'uncultured microorganisms,'" said Valerie De Anda, first author of the new paper, referring to specimens collected by other researchers from hot springs in South Africa and Wyoming's Yellowstone, and from lake sediments in Indonesia and Rwanda. "There were genetic sequences going back decades, but none of them were complete. So, we reconstructed the first genomes in this phylum and then we realized, wow, they are around the world and have been completely overlooked."

The Brockarchaeota are part of a larger, poorly studied group of microbes called archaea. Until now, scientists thought that the only archaea involved in breaking down methylated compounds--that is, decaying plants, phytoplankton and other organic matter--were those that also produced the greenhouse gas methane.

"They are using a novel metabolism that we didn't know existed in archaea," said De Anda. "And this is very important because marine sediments are the biggest reservoir of organic carbon on Earth. These archaea are recycling carbon without producing methane. This gives them a unique ecological position in nature."

A phylum is a broad group of related organisms. To get a sense of just how large and diverse phyla are, consider that the phylum Chordata alone includes fish, amphibians, reptiles, birds, mammals and sea squirts. The phylum Arthropoda, which accounts for about 80% of all animals, includes insects, arachnids (such as spiders, scorpions and ticks) and crustaceans (crabs, lobsters, shrimp, and other tasty sea denizens).

In July 2020, Baker, De Anda and others suggested the possible existence of several new phyla among the archaea, including Brockarchaeota, in a review article in Nature Microbiology. This latest study adds more than a dozen new species to Brockarchaeota, describes their metabolism and demonstrates that they are indeed a distinctly new phylum.

In addition to breaking down organic matter, these newly described microbes have other metabolic pathways that De Anda speculates might someday be useful in applications ranging from biotechnology to agriculture to biofuels.

The Environmental Protection Agency (EPA) largely remedies Superfund sites containing asbestos by capping them with soil to lock the buried toxin in place. But new research suggests that this may actually increase the likelihood of human exposure to the cancer-causing mineral.

"People have this idea that asbestos is all covered up and taken care of," said Jane Willenbring, who is an associate professor of geological sciences at Stanford University's School of Earth, Energy & Environmental Sciences (Stanford Earth). "But this is still a lingering legacy pollutant and might be dribbling out pollution, little by little."

Willenbring has published several studies about asbestos behavior and, most recently, turned her attention to the lack of information about how asbestos may move through the soils where it is stored. Through lab experiments with asbestos fibers, which were detailed in a paper published Jan. 27 in the Journal of Hazardous Materials Letters, she and colleagues determined that the soil's organic material actually enables the asbestos to move through the ground and potentially into nearby water supplies.

They found that dissolved organic matter changes the electric charge on asbestos particles and makes them less sticky, thereby enabling them to move faster through soil. The work disproves the prevailing theory that asbestos fibers cannot easily move through soil - an assumption that has been made in part because of the mineral's hair-like shape.

"It's surprising that even though these little fibers are so long, because their shortest diameter is small enough, they can wind their way through these soil pores," said Willenbring, who is senior author on the study.

Inhalation of asbestos increases the risk of developing lung disease and lung cancer, and exposure could occur through irrigation, taking showers, using humidifiers or other unfiltered sources that disperse water into the air.

A legacy pollutant

Asbestos is a naturally occurring mineral that mainly forms in the subsurface, at the boundary of Earth's oceanic and continental crusts. For much of the 20th century, it was revered as a miracle building material for its high heat capacity and insulation properties, and mining and production boomed worldwide. Following widespread evidence of its link to cancer, including a rare and aggressive form called mesothelioma, production of asbestos in the U.S. declined dramatically starting in the 1970s.

In addition to thinking that the shape of the fibers would inhibit transport, the scientific community has been influenced by a 1977 EPA report that minimized the threat of asbestos moving through soil. Since then, new findings about the role of colloids - microscopic particles that remain dispersed within solutions rather than settling to the bottom - have led researchers to challenge the assumption that asbestos stays fixed in soil.

"Now we can show that exactly the thing that they do, which is add manure or other organic sludge to the asbestos piles that creates the production of dissolved organic matter, is exactly what causes the liberation of asbestos," Willenbring said. "It's actually facilitating the transport of asbestos fibers."

In some ways, the team's breakthrough about asbestos is not surprising because it aligns so closely with recent findings about the transport of colloids in soil, Willenbring said. But she was stunned by the scale of the problem: Millions of people in the U.S. are living near thousands of sites contaminated with asbestos.

At least 16 Superfund sites contain asbestos and areas where the mineral naturally occurs can also pose a risk.

Improving remediation

As part of the lab experiments, Willenbring and her team sampled soil from the BoRit Superfund Site in Ambler, Pennsylvania before it was capped in 2008. The waste dump is located next to a reservoir, as well as a stream that feeds water to the city of Philadelphia.

However, there is a silver lining to the team's discovery.

"Not all types of dissolved organic matter have the same effect on asbestos mobility," said lead study author Sanjay Mohanty, an assistant professor at UCLA's Civil and Environmental Engineering who collaborated with Willenbring on the experiments. "Thus, by identifying the types that have the worst effect, the remediation design could exclude those organic amendments."

As part of the remediation strategy, some sites include vegetation planted on top of the soil to prevent erosion. Willenbring's ongoing research involves figuring out how fungal-vegetation associations may be able to extract iron and make the asbestos fibers less toxic to people.

"It's not just inflammation in the lungs that's a problem - there's a process by which iron contained in the asbestos fiber is actually responsible for causing DNA damage, which can lead to cancer or mesothelioma," Willenbring said.

Single-molecule fluorescence detection (SMFD) is able to probe, one molecule at a time, dynamical processes that are crucial for understanding functional mechanisms in biosystems. Fluorescence in the Near-infrared (NIR) offers improved Signal to Noise Ratio (SNR) by reducing the scattering, absorption and autofluorescence from biological cellular or tissue samples, therefore, provides high imaging resolution with increased tissue penetration depth that are important for biomedical applications. However, most NIR-emitters suffer from low quantum yield, the weak NIR fluorescence signal makes the detection extremely difficult.

Plasmonic nanostructures are capable of converting localized electromagnetic energy into free radiation and vice versa. This capability makes them efficient nano-antennas for modulating molecular fluorescence. The plasmonic nano-antenna generally enhances the fluorescence of a nearby molecule by enhancing the excitation rate and the quantum yield of the molecule. In order to optimally enhance the fluorescence, the plasmonic mode of the nano-antenna has to 1) couple strongly to the molecule and 2) radiate strongly to free space. Simultaneously satisfying the two requirements poses a challenge that is impossible to overcome in conventional, symmetric plasmonic nanostructures.

In a new paper published in Light Science & Application, scientists from the State Key Laboratory of Surface Physics, Physics Department of Fudan University, China, establishes a novel, universal approach to enhance single-molecule fluorescence in the NIR regime without compromising the molecule's photostability.

They construct asymmetric nano-antennas consisting of two bars with unequal lengths (Fig. 1) that provide multiple plasmonic modes with tunable resonance frequencies matching both excitation and emission frequencies of the fluorophore. The added tuning parameter, i.e., the ratio of the bar lengths, in such asymmetric structures offers new possibilities to modulate the near-field and far-field properties of the plasmonic modes, thereby further improving both excitation and emission processes. As a result, they experimentally acquire a single-molecule fluorescence enhancement factor up to 405 (Fig. 2), and the corresponding theoretical calculations indicate the quantum yield can be as high as 80%. Because the quantum yield plays a major role in this setup, this enhancement is achieved without sacrificing the molecules' survival time under laser irradiation.

In addition, compared with reference groups of molecules located on glass substrate, the authors have observed a significantly increased photobleaching time in molecules located around asymmetric double-bar nano-antennas (Fig. 3), indicating a much higher number of fluorescence photons emitted by those molecules. The nano-antennas are, therefore, able to drastically suppress photobleaching. Because the local field enhancement does not improve photostability, the suppression comes mainly from the increased quantum yield as a result of competition between photobleaching rate and energy transfer rate to antenna.

Strawberry geranium (Saxifraga stolonifera) has been used in Japan as a herbal medicine to treat wounds and swelling, and continues to be an ingredient in food and cosmetics. Pharmacological studies have shown that extracts of strawberry geranium have antioxidant and antitumor activities. However, the anti-inflammatory effect of strawberry geranium on the skin had not been well characterized.

This study, first-authored by associate professor Takeshi Kawahara of the Institute of Agriculture, Shinshu University for a joint research project with Maruzen Pharmaceutical Co., Ltd. succeeded in obtaining results which showed that the suppression of excessive immune response mediated by Toll-like receptor 2 (TLR2) to infectious microorganisms of skin keratinocytes which indicates strawberry geranium, called yukinoshita in Japanese can be a means of resolving routine infectious dermatitis.

Antibiotics against microorganisms and steroid-like components that suppress inflammation are generally used to control dermatitis, but the emergence of resistant bacteria and side effects due to chronic use are making them less desirable. Strawberry geranium provides a means to locally control inflammation on the body by provoking a limited immune response.

Yukinoshita, which means below the snow in Japanese, is a highly safe plant substance with a proven track record that has been used for centuries as foods and in cosmetics. Saxifraga stolonifera is also known as a crude drug and though its anti-inflammatory effect has been known, the detailed mechanism of action had not been elucidated. It is expected to be applied as an anti-inflammatory material based on the expression-suppressing effect of the TLR2 molecule clarified by this study.

Based on the results of this research, the research group is planning to conduct an efficacy test for people with mild acne. This approach has a different mechanism of action from conventional anti-inflammatory agents, but if useful results are obtained, it is expected that strawberry geranium can be widely used as an anti-inflammatory substance.

A team led by Prof. GUO Guangcan and Prof. ZOU Changling from the University of Science and Technology of China of the Chinese Academy of Sciences realized efficient frequency conversion in microresonators via a degenerate sum-frequency process, and achieved cross-band frequency conversion and amplification of converted signal through observing the cascaded nonlinear optical effects inside the microresonator. The study was published in Physics Review Letters.

Coherent frequency conversion process has wide application in classical and quantum information fields such as communication, detection, sensing, and imaging. As a bridge connecting wavebands between fiber telecommunications and atomic transition, coherent frequency conversion is a necessary interface for distributed quantum computing and quantum networks.

Integrated nonlinear photonic chip stands out because of its significant technological advances of improving nonlinear optical effects by microresonator's enhancing the light-matter interaction, along with other advantages like small size, great scalability, and low energy consumption. These make integrated nonlinear photonic chips an important platform to covert optical frequency efficiently and realize other nonlinear optical effects.

However, the on-chip resonant-enhanced coherent frequency conversion requires multiple (three or more) modes of phase matching condition among distinct wavelengths, which imposes significant challenges to the devices' design, fabrication, and modulation. Especially in the application of atomic and molecular spectroscopy, the intrinsic error brought by nanofabrication technique of integrated nonlinear photonic chips makes the resonant frequency of microresonator hard to match atomic transition frequency.

The researchers in this study proposed a new scheme for high-efficiency coherent frequency conversion requiring only the two-mode phase matching condition via a degenerate sum-frequency process. They achieved precise tuning of the frequency window (FW): coarse tuning by adjusting the device temperature with a tuning range of 100 GHz; fine tuning with MHz level based on previous work of all-optical thermal control in an integrated microcavity.

The results showed that the best achieved efficiency was up to 42% during the photon-number conversion from 1560-nm-wide to 780-nm-wide wavelength, indicating a frequency tuning bandwidth over 250GHz. This satisfied the interconnection of telecom photons and rubidium (Rb) atoms.

Besides, the researchers experimentally verified cascaded χ(2) and Kerr nonlinear optical effects inside a single microresonator to amplify the converted signal, which was neglected before. Thus the highest conversion efficiency was potential to achieve over 100% through adjusting device fabrication parameters, fulfilling simultaneously signal converted and amplified.

This study provides a novel way for efficient on-chip frequency conversion, which is extremely important for on-chip quantum information processing.

A new study conducted jointly by the University of Liege (Belgium) and the Ecole normale superieure - PSL (France) shows that heart brain interactions, measured using electroencephalography (EEG), provide a novel diagnostic avenue for patients with disorders of consciousness. This study is published in the Journal of Neuroscience.

Catherine Tallon-Baudry (ENS, CNRS) introduces : "The scientific community already knew that in healthy participants, the brain's response to heartbeats is related to perceptual, bodily and self-consciousness. We now show that we can obtain clinically meaningful information if we probe this interaction in patients with disorders of consciousness." In the past decades several important improvements for the diagnosis of these patients have been made, yet, it remains a big challenge to measure self-consciousness in these patients that cannot communicate.

For their study, the researchers included 68 patients with a disorder of consciousness. Fifty-five patients suffered from the minimally conscious state, and showed fluctuating but consistent signs of consciousness but were unable to communicate, and 13 patients in the unresponsive wakefulness state (previously called vegetative state) who do not show any behavioural sign of awareness. These patients were diagnosed using the coma recovery scale-revised, a standardized clinical test to assess conscious behaviour.

"As these patients suffered from severe brain injury, they might be unable to show behavioural signs of awareness. Therefore, we also based our diagnosis on the brain's metabolism as probe for consciousness. This is a state-of-the art neuroimaging technique that helps to improve the diagnosis of patients with disorders of consciousness. Although these scans are very informative, they can only be acquired in specialized centers," says Jitka Annen (GIGA Consciousness, ULiege).

The researchers recorded brain activity during resting state (i.e. without specific task or stimulation). They selected EEG segments right after a heartbeat and EEG segments at random timepoints (i.e. not time-locked to a heartbeat). They then used machine learning algorithms to classify (or diagnose) patients into the two diagnostic groups.

Diego Candia-Rivera (ENS) further comments: "EEG segments not locked to heartbeats were informative to predict if a patient was conscious or not, but EEG segments locked to heartbeats were more accurate in doing so. Our results indicate that the heartbeat evoked potential can give us supplementary evidence for the presence of consciousness."

It is important to note that the heartbeat evoked responses were more in accordance with the diagnosis based on brain metabolism than the diagnosis based on behavioural assessment. It seems therefore that the heartbeat evoked response can be used to measure a perspective of self-consciousness that is not assessed successfully using behavioural tools.

"The next challenge is to translate our findings to clinical applications so that all patients with disorders of consciousness can benefit from better diagnosis using widely available bedside assessment technologies," concludes Steven Laureys, head of GIGA Consciousness research unit and Centre du Cerveau (ULiege, CHU Liege).

Software using artificial intelligence, AI, is revolutionizing how microscopy images are analysed. For instance, AI can be used to detect features in images (i.e., tumours in biopsy samples) or improve the quality of images by removing unwanted noise. However, non-experts continue to find AI technologies difficult to use.

In the article "Democratising deep learning for microscopy with ZeroCostDL4Mic", published in Nature Communications on 15 April 2021, researchers describe a platform called ZeroCostDL4Mic, which makes these AI technologies accessible to everyone.

"The key novelty is that ZeroCostDL4Mic runs in the cloud for free and does not require users to have any coding experience or advanced computational skills. Effectively, it runs on any computer that has a web browser," says Guillaume Jacquemet, Senior Researcher in Cell Biology at Åbo Akademi University.

Over the last 400 years, microscopes have allowed mankind to observe objects that are otherwise too small to be seen with the naked eye. Today, microscopy is a leading technology used worldwide to perform not only research but also diagnostics.

Modern microscopes are directly connected to digital cameras, leading to the acquisition of hundreds to thousands of images per sample. These images need to be processed on a computer to gain meaningful data, which is a huge undertaking.

To help with the number of images, Jacquemet and his colleagues have used AI to train a machine to do the work. In practice, ZeroCostDL4Mic is a collection of self-explanatory notebooks for Google Colab, featuring an easy-to-use graphical user interface.

"We believe that ZeroCostDL4Mic will acts as 'a gateway drug' for AI, luring users to explore these new technologies that will transform biomedical research and diagnostics in the decades to come," says Jacquemet.

In celebration of the 31st anniversary of the launching of NASA's Hubble Space Telescope, astronomers aimed the renowned observatory at a brilliant "celebrity star," one of the brightest stars seen in our galaxy, surrounded by a glowing halo of gas and dust.

The price for the monster star's opulence is "living on the edge." The star, called AG Carinae, is waging a tug-of-war between gravity and radiation to avoid self-destruction.

The expanding shell of gas and dust that surrounds the star is about five light-years wide, which equals the distance from here to the nearest star beyond the Sun, Proxima Centauri.

The huge structure was created from one or more giant eruptions about 10,000 years ago. The star's outer layers were blown into space - like a boiling teapot popping off its lid. The expelled material amounts to roughly 10 times our Sun's mass.

These outbursts are the typical life of a rare breed of star called a luminous blue variable, a brief convulsive phase in the short life of an ultra-bright, glamorous star that lives fast and dies young. These stars are among the most massive and brightest stars known. They live for only a few million years, compared to the roughly 10-billion-year lifetime of our Sun. AG Carinae is a few million years old and resides 20,000 light-years away inside our Milky Way galaxy.

Luminous blue variables exhibit a dual personality: They appear to spend years in quiescent bliss and then they erupt in a petulant outburst. These behemoths are stars in the extreme, far different from normal stars like our Sun. In fact, AG Carinae is estimated to be up to 70 times more massive than our Sun and shines with the blinding brilliance of one million suns.

"I like studying these kinds of stars because I am fascinated by their instability. They are doing something weird," said Kerstin Weis, a luminous blue variable expert at Ruhr University in Bochum, Germany.

Major outbursts such as the one that produced the nebula occur once or twice during a luminous blue variable's lifetime. A luminous blue variable star only casts off material when it is in danger of self-destruction as a supernova. Because of their massive forms and super-hot temperatures, luminous blue variable stars like AG Carinae are in a constant battle to maintain stability.

It's an arm-wrestling contest between radiation pressure from within the star pushing outward and gravity pressing inward. This cosmic match results in the star expanding and contracting. The outward pressure occasionally wins the battle, and the star expands to such an immense size that it blows off its outer layers, like a volcano erupting. But this outburst only happens when the star is on the verge of coming apart. After the star ejects the material, it contracts to its normal size, settles back down, and becomes quiescent for a while.

Like many other luminous blue variables, AG Carinae remains unstable. It has experienced lesser outbursts that have not been as powerful as the one that created the present nebula.

Although AG Carinae is quiescent now, as a super-hot star it continues pouring out searing radiation and powerful stellar wind (streams of charged particles). This outflow continues shaping the ancient nebula, sculpting intricate structures as outflowing gas slams into the slower-moving outer nebula. The wind is traveling at up to 670,000 miles per hour (one million km/hr), about 10 times faster than the expanding nebula. Over time, the hot wind catches up with the cooler expelled material, plows into it, and pushes it farther away from the star. This "snowplow" effect has cleared a cavity around the star.

The red material is glowing hydrogen gas laced with nitrogen gas. The diffuse red material at upper left pinpoints where the wind has broken through a tenuous region of material and swept it into space.

The most prominent features, highlighted in blue, are filamentary structures shaped like tadpoles and lopsided bubbles. These structures are dust clumps illuminated by the star's reflected light. The tadpole-shaped features, most prominent at left and bottom, are denser dust clumps that have been sculpted by the stellar wind. Hubble's sharp vision reveals these delicate-looking structures in great detail.

The image was taken in visible and ultraviolet light. Ultraviolet light offers a slightly clearer view of the filamentary dust structures that extend all the way down toward the star. Hubble is ideally suited for ultraviolet-light observations because this wavelength range can only be viewed from space.

Massive stars, like AG Carinae, are important to astronomers because of their far-reaching effects on their environment. The largest program in Hubble's history - the Ultraviolet Legacy Library of Young Stars as Essential Standards - is studying the ultraviolet light of young stars and the way they shape their surroundings.

Luminous blue variable stars are rare: Less than 50 are known among the galaxies in our local group of neighboring galaxies. These stars spend tens of thousands of years in this phase, a blink of an eye in cosmic time. Many are expected to end their lives in titanic supernova blasts, which enrich the universe with heavier elements beyond iron.

ABERDEEN PROVING GROUND, Md. -- Army and Arizona State University researchers identified a set of approaches to help scientists assess how well autonomous systems and humans communicate.

These approaches build on transformational scientific research efforts led by the Army's Robotics Collaborative Technology Alliance, which evolved the state of robots from tools to teammates and laid the foundation for much of the service's existing research into how humans and robots can work together effectively.

As ideas for autonomous systems evolve, and the possibilities of ever-more diverse human-autonomy teams has become a reality; however, no clear guidelines exist to explain the best ways to assess how well humans and intelligent systems communicate, Army researchers said.

"The future Army is going to have complex teams in terms of how they will involve autonomy in different ways," said Dr. Anthony Baker, postdoctoral scientist at the U.S. Combat Capabilities Development Command, known as DEVCOM, Army Research Laboratory. "There is a clear need to be able to measure communication in those types of teams because communication is what defines teamwork. It reflects how the team thinks, plans, makes decisions and succeeds or fails.

If you can't measure how the team is doing, you can't do anything to improve their performance, their decision-making, all of those things that make it more likely for the Army to maintain a decisive overmatch on the battlefield and for the warfighter to accomplish the mission, he said.

In the recently published Human-Intelligent Systems Integration journal paper Approaches for Assessing Communication in Human-Autonomy Teams, researchers listed 11 critical approaches for assessing communication in human-autonomy teams. Baker said their focus is to change Soldier involvement with those systems.

The approach considers communication structure:

Who is saying what to whom and when

Dynamics, or how interaction patterns evolve over time

Emotion, which looks at how information is communicated through facial expressions and vocal features like tone and pitch

Content, which draws on different aspects of words and phrases themselves

"If we want Soldiers and intelligent systems to work well together, we have to have the right measurement tools to analyze and study their communication because communication is so critical to how well they can perform," Baker said.

As lead author on the paper, Baker said it won't be enough to study these things after the teams are fielded.

"We need the measurement tools while those teams and technologies are being developed by the Army," he said.

Because multi-domain operations are fundamentally dependent on improving the efficiency and optimization of communications within and between domains, the goal of this cross-cutting work is for these systems to be able to work with teams more naturally, he said.

According to Baker, this work may also provide a critical roadmap for analyzing communication in complex human-autonomy team structures such as those forecasted for Next Generation Combat Vehicle operations.

"There may be a time when a smart, load-carrying mule robot should carry a squad's extra gear completely independently and without Soldier involvement, but there is also a push in some areas to make it so that if systems do need to involve Soldiers, they can do so in a way that's more natural for the Soldiers, like working with a human teammate," Baker said.

Consider how a Soldier telling a robotic system, "I need you to take that gear up the hill and wait an hour before going to the next zone," is much easier than inputting a series of buttons and switches on a remote control.

"We want intelligence assessments, command and control decisions and other important things like that to be possible with less Soldier involvement, but we still want Soldier engagement for some things, and we want it to be easier," Baker said. "Hence why the RCTA had a large focus on making Soldier-robot interactions more efficient."

The Robotics CTA was a decade-long research initiative began in 2009 that coalesced a community of researchers from the Army, academia and industry to identify scientific gaps and move the state of the art in ground combat robotics. Strategic investments in Army-led foundational research resulted in advanced science in four critical areas of ground combat robotics that effect the way U.S. warfighters see, think, move and team.

Baker said it laid the groundwork for a lot of how the Army thinks about human-robot interaction and drove the shift in how government and industry look at robots as teammates, rather than just tools.

The laboratory's Human-Autonomy Teaming essential research program, or HAT ERP, continues down paths started in the RCTA, which laid broad building blocks for how to describe, model, design and implement new ways of partnering humans and robots, which are intelligent systems with physical forms.

"RCTA was not interested in explaining or providing ways to study communication between human teammates, instead being aimed at how humans and robots communicate," Baker said. "Our work looks at it from the perspective that we will need ways to study the communication of any type of team-whether or not those teams currently involve any number of robots or autonomy. We want to be agnostic to the overall makeup of the team, so we provide communication assessments suitable for many different scenarios."

These communication assessment approaches also apply to Soldier-only teams as well.

"Imagine a future human-autonomy team that has to re-task an autonomous vehicle to go join another platoon, and now the team is just humans only," he said. "Our work seeks to provide the literature with ways to analyze communication in those teams, no matter what they look like or what they're supposed to do, so that we can draw conclusions about how well they are working together and accomplishing their goals."

Future research will seek to validate some of the approaches identified in the paper using datasets collected from Next Generation Combat Vehicle lab studies and field experiments, Baker said.

Researchers from the Faraday Institution's SOLBAT project have made a significant step in understanding how and why solid-state batteries (SSBs) fail. A paper, published in Nature Materials on 22 April, provides answers to one important piece of the scientific puzzle.

To make step changes in electric vehicle (EV) battery range and safety at a lower cost, new battery chemistries that are "beyond lithium ion" must be developed. SSBs are one such promising technology, but mass market adoption has been held back by several key technical challenges that cause the battery to fail when charged and discharged.

SSBs can short circuit after repeating charging and discharging. One well-recognised cause of battery failure is the growth of dendrites, branching networks of lithium that grow through the solid electrolyte during charging of a battery. Solving these two challenges could potentially usher in a new era of SSB-powered electric vehicles.

Researchers in the Materials, Chemistry and Engineering Science Departments at the University of Oxford, collaborating with Diamond Light Source and the Paul Scherrer Institut in Switzerland have generated strong evidence supporting one of two competing theories regarding the mechanism by which lithium metal dendrites grow through ceramic electrolytes leading to short circulates at high rates of charge.

Researchers used an imaging technique similar to that used in medical CAT scanners - X-ray computed tomography - coupled with spatially mapped X-ray diffraction, to visualise and characterise the growth of cracks and dendrites deep within an operating solid-state battery.

Conical pothole-like cracks first form in the electrolyte adjacent to the plated lithium anode. The crack propagates along a path where the porosity is above the average value of the ceramic. Metallic lithium is then deposited along the crack and this ingress drives the propagation of the cracks by widening the crack from the rear. The crack front propagates ahead of the lithium deposition, and lithium is not present at the crack tip. Only later, when lithium plates along the entire crack, does the cell finally short circuit.

Recently study on synthetic approaches toward polycyclic aromatic hydrocarbons (PAHs) as graphene with a well-defined structure has attracted much attention. A research group in Ehime University has been studying the synthesis and fundamental properties of pyrrole-fused azacoronene (HPHAC), a nitrogen-containing PAH. HPHACs are composed of electron-rich pyrroles, which are easily oxidized, and their dicationic species in particular exhibit unique features such as global aromaticity based on macrocyclic π-conjugation. However, all the compounds reported so far have bulky substituents at the periphery of the HPHAC skeleton, and thus the characterization of the physical properties of the pristine HPHAC itself or the π-electron function based on π-π interactions has not been possible.

In this study, the group has synthesized two new derivatives, one with alkyl groups at the periphery of the HPHAC skeleton and the other with concave π-planes above and below the HPHAC skeleton. The HPHAC with alkyl groups was found to be more readily oxidized than the compounds previously reported and to exhibit stable redox properties. In addition, reflecting its planar structure, the HPHAC forms an alternating stacked column structure with electron-deficient π-electron compounds. On the other hand, the HPHAC with an extended π-electron system exhibits an unusual π-electron function with a double concave surface. Reflecting its shape, this electron-rich HPHAC strongly interacts with spherical fullerene, which is an electron-deficient π-electron compound. A comparison of the global aromaticities of the two dicationic species reveals that the double-concave HPHAC possesses weaker aromaticity.

Recent research on π-electron materials has led to the synthesis of three-dimensional structures, such as bowl- and saddle-shaped compounds, instead of the conventional planar ones. However, there have been few studies focusing on the π-electron function of the 3D structure, except for clarifying its structural features using single crystal X-ray structure analysis. By elucidating the detailed structure-property relationships between analogues that share the same skeleton but have different 3D structures, new design guidelines can be obtained for organic electronics and spintronics materials involving π-electron functions.

In two landmark studies, researchers have used cutting-edge genomic tools to investigate the potential health effects of exposure to ionizing radiation, a known carcinogen, from the 1986 accident at the Chernobyl nuclear power plant in northern Ukraine. One study found no evidence that radiation exposure to parents resulted in new genetic changes being passed from parent to child. The second study documented the genetic changes in the tumors of people who developed thyroid cancer after being exposed as children or fetuses to the radiation released by the accident.

The findings, published around the 35th anniversary of the disaster, are from international teams of investigators led by researchers at the National Cancer Institute (NCI), part of the National Institutes of Health. The studies were published online in Science on April 22.

"Scientific questions about the effects of radiation on human health have been investigated since the atomic bombings of Hiroshima and Nagasaki and have been raised again by Chernobyl and by the nuclear accident that followed the tsunami in Fukushima, Japan," said Stephen J. Chanock, M.D., director of NCI's Division of Cancer Epidemiology and Genetics (DCEG). "In recent years, advances in DNA sequencing technology have enabled us to begin to address some of the important questions, in part through comprehensive genomic analyses carried out in well-designed epidemiological studies."

The Chernobyl accident exposed millions of people in the surrounding region to radioactive contaminants. Studies have provided much of today's knowledge about cancers caused by radiation exposures from nuclear power plant accidents. The new research builds on this foundation using next-generation DNA sequencing and other genomic characterization tools to analyze biospecimens from people in Ukraine who were affected by the disaster.

The first study investigated the long-standing question of whether radiation exposure results in genetic changes that can be passed from parent to offspring, as has been suggested by some studies in animals. To answer this question, Dr. Chanock and his colleagues analyzed the complete genomes of 130 people born between 1987 and 2002 and their 105 mother-father pairs.

One or both of the parents had been workers who helped clean up from the accident or had been evacuated because they lived in close proximity to the accident site. Each parent was evaluated for protracted exposure to ionizing radiation, which may have occurred through the consumption of contaminated milk (that is, milk from cows that grazed on pastures that had been contaminated by radioactive fallout). The mothers and fathers experienced a range of radiation doses.

The researchers analyzed the genomes of adult children for an increase in a particular type of inherited genetic change known as de novo mutations. De novo mutations are genetic changes that arise randomly in a person's gametes (sperm and eggs) and can be transmitted to their offspring but are not observed in the parents.

For the range of radiation exposures experienced by the parents in the study, there was no evidence from the whole-genome sequencing data of an increase in the number or types of de novo mutations in their children born between 46 weeks and 15 years after the accident. The number of de novo mutations observed in these children were highly similar to those of the general population with comparable characteristics. As a result, the findings suggest that the ionizing radiation exposure from the accident had a minimal, if any, impact on the health of the subsequent generation.

"We view these results as very reassuring for people who were living in Fukushima at the time of the accident in 2011," said Dr. Chanock. "The radiation doses in Japan are known to have been lower than those recorded at Chernobyl."

In the second study, researchers used next-generation sequencing to profile the genetic changes in thyroid cancers that developed in 359 people exposed as children or in utero to ionizing radiation from radioactive iodine (I-131) released by the Chernobyl nuclear accident and in 81 unexposed individuals born more than nine months after the accident. Increased risk of thyroid cancer has been one of the most important adverse health effects observed after the accident.

The energy from ionizing radiation breaks the chemical bonds in DNA, resulting in a number of different types of damage. The new study highlights the importance of a particular kind of DNA damage that involves breaks in both DNA strands in the thyroid tumors. The association between DNA double-strand breaks and radiation exposure was stronger for children exposed at younger ages.

Next, the researchers identified the candidate "drivers" of the cancer in each tumor -- the key genes in which alterations enabled the cancers to grow and survive. They identified the drivers in more than 95% of the tumors. Nearly all the alterations involved genes in the same signaling pathway, called the mitogen-activated protein kinase (MAPK) pathway, including the genes BRAF, RAS, and RET.

The set of affected genes is similar to what has been reported in previous studies of thyroid cancer. However, the researchers observed a shift in the distribution of the types of mutations in the genes. Specifically, in the Chernobyl study, thyroid cancers that occurred in people exposed to higher radiation doses as children were more likely to result from gene fusions (when both strands of DNA are broken and then the wrong pieces are joined back together), whereas those in unexposed people or those exposed to low levels of radiation were more likely to result from point mutations (single base-pair changes in a key part of a gene).

The results suggest that DNA double-strand breaks may be an early genetic change following exposure to radiation in the environment that subsequently enables the growth of thyroid cancers. Their findings provide a foundation for further studies of radiation-induced cancers, particularly those that involve differences in risk as a function of both dose and age, the researchers added.

"An exciting aspect of this research was the opportunity to link the genomic characteristics of the tumor with information about the radiation dose -- the risk factor that potentially caused the cancer," said Lindsay M. Morton, Ph.D., deputy chief of the Radiation Epidemiology Branch in DCEG, who led the study.

"The Cancer Genome Atlas set the standard for how to comprehensively profile tumor characteristics," Dr. Morton continued. "We extended that approach to complete the first large genomic landscape study in which the potential carcinogenic exposure was well-characterized, enabling us to investigate the relationship between specific tumor characteristics and radiation dose."

She noted that the study was made possible by the creation of the Chernobyl Tissue Bank about two decades ago -- long before the technology had been developed to conduct the kind of genomic and molecular studies that are common today.

"These studies represent the first time our group has done molecular studies using the biospecimens that were collected by our colleagues in Ukraine," Dr. Morton said. "The tissue bank was set up by visionary scientists to collect tumor samples from residents in highly contaminated regions who developed thyroid cancer. These scientists recognized that there would be substantial advances in technology in the future, and the research community is now benefiting from their foresight."

- Recent discoveries focused on manipulation of atomically-thin 2D materials, while the new breakthrough can be used to stack technologically-relevant 3D materials at a twist angle

- Method allows continuous, systematic control of optical emission intensity and energy, and can produce ultraviolet emissions at room temperature for bulk systems

- The discovery can be significant for applications in medicine, environmental or information technologies.

Singapore, 22 April 2021 - Researchers from the Low Energy Electronic Systems (LEES) Interdisciplinary Research Group (IRG) at Singapore-MIT Alliance for Research and Technology (SMART), MIT's research enterprise in Singapore together with Massachusetts Institute of Technology (MIT) and National University of Singapore (NUS) have discovered a new way to control light emission from materials.

Controlling the properties of materials has been the driving force behind most modern technologies - from solar panels, computers, smart vehicles or life-saving hospital equipment. But materials properties have traditionally been adjusted based on their composition, structure, and sometimes size, and most practical devices that produce or generate light use layers of materials of different compositions that can often be difficult to grow.

The breakthrough by SMART researchers and their collaborators offers a new paradigm-shifting approach to tune the optical properties of technologically-relevant materials by changing the twist angle between stacked films, at room temperature. Their findings could have a huge impact on various applications in the medical, biological, and quantum information fields. The team explain their research in a paper titled "Tunable Optical Properties of Thin Films Controlled by the Interface Twist Angle" recently published in the prestigious journal Nano Letters.

"A number of new physical phenomena - such as unconventional superconductivity - have been discovered recently by stacking individual layers of atomically-thin materials on top of each other at a twist angle, which results in the formation of what we call moiré superlattices," says corresponding author of the paper, Professor Silvija Gradecak from the Department of Materials Science and Engineering at NUS and Principal Investigator at SMART LEES. "The existing methods focus on stacking only thin individual monolayers of film which is laborious, while our discovery would be applicable to thick films as well - making the process of materials discovery much more efficient."

Their research can also be meaningful for developing the fundamental physics in the field of "twistronics" - the study of how the angle between layers of two-dimensional materials can change their electrical properties. Professor Gradecak points out the field has so far focused on stacking individual monolayers, which requires careful exfoliation and may suffer from relaxation from a twisted state, thus limiting their practical applications. The team's discovery could make this groundbreaking twist-related phenomenon applicable to thick film systems as well, which are easy to manipulate and industrially relevant.

"Our experiments showed that the same phenomena leading to formation of moiré superlattices in two-dimensional systems can be translated to tune optical properties of three-dimensional, bulk-like hexagonal boron nitride (hBN) even at room temperature," said Hae Yeon Lee, the lead author of the paper and a Materials Science and Engineering Ph.D. candidate at MIT. "We found that both the intensity and colour of stacked, thick hBN films can be continuously tuned by their relative twist angles and intensity increased by more than 40 times."

The research results open up a new way to control optical properties of thin films beyond the conventionally used structures especially for applications in medicine, environmental or information technologies.

Two-dimensional (2D) materials with a single-layer thickness retaining magnetic order in atomically thin limit began to increase their scientific and technological significance after the successful synthesis of graphene and later investigations of van der Waals materials. CrBr3 has been known since the 60s as a van der Waals ferromagnet. Hansen, Tsubokawa, and Dillon have pioneered the work on magnetism in this compound. However, it has only recently been established that CrBr3 exhibits ferromagnetism when exfoliating to several layers and monolayers while saving its magnetic order. Nevertheless, no systematic experimental data simultaneously investigating the temperature behavior of the crystal, the magnetic structure of CrBr3 have been reported in sufficient detail. This fact was the impetus for the team to perform studies.

The paper focuses on the investigations of crystal, magnetic structures and vibrational properties of CrBr3 upon cooling. The methods of neutron and X-ray powder diffraction supplemented by Raman spectroscopy data allowed the authors to provide a consistent and complete microscopic picture for a temperature behavior of microscopic properties of the model ferromagnetic van der Waals CrBr3 material. Neutron diffraction made it possible to study in detail the role of structural parameters across the paramagnetic-ferromagnetic phase transition in coupling with the study of the magnetic structure of CrBr3. Mainly, anomalies in the temperature behavior of the parameters of the crystal structure, interatomic distances, and angles below Curie temperature were revealed. The most important finding of the manuscript is the negative thermal volume expansion phenomenon observed in CrBr3 below the Curie temperature. The negative thermal expansion is the rare effect found for a limited number of materials. In addition, the obtained Raman data provide new information on temperature variation of vibrational modes across the transition to ferromagnetic state, uncovering spin-phonon coupling effects. The information about thermal expansion behavior is especially important for fabrication of heterostructures involving van der Waals materials and their practical applications. The obtained results of the work are very important for current understanding in the physics of 2D van der Waals materials and may serve as a background for subsequent theoretical calculations and development of general models describing the structural, electronic and magnetic properties of 2D ferromagnetic van der Waals materials in bulk and atomically thin forms.

The recently reported magnetic ordering in two-dimensional materials, such as chromium tribromide (CrBr3), opens new possibilities for fabrication of magnetoelectronic devices based on 2D systems, which can be also be combined in heterostructures. With the unusual magnetic properties and the possibility of existing in monolayer form, chromium trihalides are promising materials for ultrathin spintronics.

There is a number of still unexplored phenomena in this area. In the future, the researchers plan to investigate the structural and magnetic properties of CrBr3 under extreme conditions to improve the understanding of the observed physical phenomena. Van der Waals compounds with a different composition are also a promising topic.

A small proportion of women who receive anti-estrogen treatment after breast cancer surgery have worse outcomes. This is associated with mutations in the estrogen receptor gene, according to a study from Lund University now published in JNCI Cancer Spectrum.

"If our results are confirmed in further studies, it would be relevant to screen for these resistance mutations already at diagnosis, and then consider other treatment options that could work better for patients with mutated tumors," says Lao Saal, who led the study, the largest of its kind on resistance mutations in the estrogen receptor in primary breast cancer.

Breast cancer is the most common type of cancer in women. The majority of breast tumors have high levels of the estrogen receptor (encoded by the gene ESR1), and after surgical removal of the cancer, the most important treatment for these women are anti-hormonal drugs that reduce the activity of the estrogen receptor and thereby reduce the risk of relapse.

The researchers focused on the mutations in the estrogen receptor ESR1 gene, which had been previously discovered to be common in relapsed breast cancer in women who had received prior anti-estrogen cancer treatment. The mutations made the tumor resistant to the hormonal treatment. Recent studies, however, showed that the incidence of these resistance mutations was very low in patients at the first diagnosis of cancer, and no studies explored how such pre-existing mutations might be related to response to anti-hormonal treatments.

The Lund researchers analyzed RNA-sequencing data from more than 3,000 breast tumors from within the large SCAN-B research project, samples taken before treatment with drugs. Among the 2,720 tumors positive for the estrogen receptor and therefore eligible for hormonal treatment, they found 29 tumors with an ESR1 resistance mutation. All mutations were found in patients older than 50 years.

"We investigated whether the resistance mutations, which occurred before cancer treatment, affected the patients' survival and saw that patients with a mutation in their primary tumor had three times higher risk of recurrence and 2.5 times higher risk of dying. The link between the mutations and poor survival was also seen after statistical corrections for age or for other factors that may affect the outcome for the patient," says doctoral student Malin Dahlgren.

"This not only confirms what previous studies have shown, that the mutations are relatively rare, but we now show that these resistant mutations occur in about 1 percent of breast cancer cases already at initial diagnosis and we are the first to show that these patients seem to respond less well to hormonal treatment. If the results can be verified in further studies, it may be relevant to consider other treatment options for these patients," concludes Lao Saal.