A study reporting the researchers’ findings was published April 13 in the journal Accident Analysis and Prevention.

Traffic accidents involving large trucks in the United States have increased 47 percent according to the National Safety Council, and in 2021, these vehicles were responsible for nine percent of all vehicles involved in fatal crashes. Several studies worldwide have highlighted in particular the severity of collisions related to drowsy driving and their substantial risk of fatality.

A major risk here comes from what researchers term “microsleeps.” A microsleep is a brief episode of sleep that lasts for just a few seconds and can occur involuntarily during wakefulness. It can lead to impaired cognitive and motor performance, including slower reaction times, decreased attention, and even complete loss of consciousness. Microsleep episodes can have a significant impact on driving performance and increase the likelihood of dozing off while driving. In 2022, National Police Agency of Japan announced that falling asleep at the wheel was to be included in the same category of “forward inattention” as distraction, which has been the most frequent cause of fatal traffic accidents in the country for over ten years.

A great deal of research into typical microsleep behaviors has investigated one or more aspects of the problem such as eye closure or changes in pupil diameter. No study has yet performed an analysis that takes a more holistic approach considering multiple aspects of the problem, combining the driver’s eye and mouth movements as well as their entire body and vehicle driving behavior. Most such studies have also only considered driver performance during computer simulations. No research has yet looked at actual collisions of large trucks.

“But in recent years, there has been an explosion in the use of dashcam video recorders,” said Hajime Kumagai, lead author of the paper and a specialist in sleep medicine with the Graduate School of Biomedical and Health Sciences at Hiroshima University.

“This means that a great many traffic accidents, and their possible relationship to episodes of microsleeping have been recorded. This inspired us to employ dashcam footage to investigate microsleep-related behaviors immediately prior to real-world truck collisions.”

In total, the researchers reviewed 3,120 seconds of video footage from interior and exterior dashcams across 52 cases from truck collisions in Japan that had actually happened. They analysed the footage from one minute before the crash right up until the crash. In each incident, the person at the wheel had been a professional driver, and all crashes occurred on either urban roads or highways.

The footage was visually analyzed in a second-by-second manner to simultaneously evaluate any eye changes and microsleep-related activity including the driver’s actions to try to prevent falling asleep (anti-sleepiness behaviors), behavioral signs of microsleep, and abnormal vehicle behavior.

The researchers concluded that the key signs of microsleep include behaviors suggesting a creeping sleepiness, such as the absence of body movement, relaxation of antigravity muscles (the muscles such as back and neck muscles, as well as calves and quadriceps used to support ourselves against the force of gravity), eyes being half-closed, and closure of the eyes for one second or more.

“Up to now, technologies used to attempt to detect and counter falling asleep at the wheel have focused mainly on monitoring the driver’s eyes,” said Toshiaki Shiomi, a co-author of the study. “What we found means that it is crucial to monitor not just the eyes but also the driver’s whole body, as well as vehicle behavior in order to reliably detect microsleep-related activity.”

This should also help in avoiding false alarms by ensuring a clear distinction between microsleep-related and non-microsleep-related behaviors.

Developing advanced safety systems that can detect and alert drivers of potential microsleep episodes involving a whole-of-body approach combined with monitoring of the vehicle for typical microsleep-related abnormal vehicle maneuvers could be an effective intervention for reducing accidents in the trucking industry.

The team hopes now to support work developing such advanced safety systems. These might include technologies that monitor both the inside and outside of the truck using cameras or other sensors, as well as deployment of algorithms that can analyze such data in real-time to detect signs of sleepiness or fatigue. These systems could then alert drivers with an alarm when they are at risk of falling asleep at the wheel.

The PCE (Power-conversion efficiency), a measure of the power generated from a given solar irradiation, is considered a significant benchmark for the performance of photovoltaics (PVs), or solar panels, in power generation. The improved efficiency of over 19% that was achieved by the PolyU researchers constitutes a record for binary OSCs, which have one donor and one acceptor in the photo-active layer.

Led by Prof. LI Gang, Chair Professor of Energy Conversion Technology and Sir Sze-Yen Chung Endowed Professor in Renewable Energy at PolyU, the research team invented a novel OSC morphology-regulating technique by using 1,3,5-trichlorobenzene as a crystallisation regulator. This new technique boosts OSC efficiency and stability.

The team developed a non-monotonic intermediated state manipulation (ISM) strategy to manipulate the bulk-heterojunction (BHJ) OSC morphology, which simultaneously optimises crystallisation dynamics and energy loss of non-fullerene OSCs. Unlike the strategy of using traditional solvent additives, which is based on excessive molecular aggregation in films, the ISM strategy promotes the formation of more ordered molecular stacking and favourable molecular aggregation. As a result, the PCE was considerably increased and the undesirable non-radiative recombination loss was reduced. Notably, non-radiative recombination lowers the light generation efficiency and increases the heat loss.

The research team’s findings are described in the study “19.3% Binary Organic Solar Cell and Low Non-Radiative Recombination Enabled by Non-Monotonic Intermediate State Transition” published in Nature Communications . The conversion of solar energy to electricity is an essential technology for achieving a sustainable environment. Although OSCs are promising devices that harness solar energy cost-effectively, their efficiency must be improved if they are to be used widely in practical applications.

Non-fullerene acceptors based organic solar cells represent the frontier of research in the field of organic photovoltaics due to both the materials and morphology manipulation innovations. Nevertheless, non-radiative recombination loss suppress and performance boosting are in the centre of organic cell research.

Prof. Li said, “Challenges in research came from the existing additive-based benchmark morphology control methods, which suffer from non-radiative recombination loss, thus lowering the open-circuit voltage due to excessive aggregation.” The research team took about two years to devise a non-monotonic ISM strategy for increasing the OSC efficiency and lowering the non-radiative recombination loss. The publication of the study promises to galvanise OSC research.

Prof. Li said, “The new finding will make OSC research an exciting field, and this will likely create tremendous opportunities in applications like portable electronics and building-integrated PVs.” The new door will open when low cost single-junction OSCs can achieve a PCE of over 20%, along with more stable performance and other unique advantages such as flexibility, transparency, stretchability, low weight and tuneable colour.

Prof. Li has been recognised as a Highly Cited Researcher 9 years in a row since 2014, which testifies to his significant impact on global research. His pioneering contributions to research on polymer solar cells since 2005 have brought sustainable influence on printable solar energy development with global recognition.

Underpinning the research on OPV field, Prof LI’s study titled, “High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends,” was published on Nature Materials in 2005. This represented OPV’s first generation research breakthrough which has fuelled solar technology from this frontier study.

In 2010, Prof LI’s study titled “For the Bright Future — Bulk Heterojunction Polymer Solar Cells with Power Conversion Efficiency of 7.4%” was published on Advanced Materials.

Prof. Li said, “The latest study shows a record low non-radiative recombination loss of 0.168 eV in a binary OSC with a PCE of over 19%. This is a very encouraging result for the long-standing research on OSCs that I have conducted over the past two decades. We have already achieved better OSC efficiency, and this will subsequently help accelerate the applications of solar energy.”

References: Nature Materials 4, 864-868 (2005). High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends. Advanced Materials Vol. 22, Issue 20 (2010). For the Bright Future — Bulk Heterojunction Polymer Solar Cells with Power Conversion Efficiency of 7.4%.

Penn State scientists have discovered a new mechanism by which bacteria can select between different rare earth elements, using the ability of a bacterial protein to bind to another unit of itself, or “dimerize,” when it is bound to certain rare earths, but prefer to remain a single unit, or “monomer,” when bound to others.

By figuring out how this molecular handshake works at the atomic level, the researchers have found a way to separate these similar metals from one another quickly, efficiently, and under normal room temperature conditions. This strategy could lead to more efficient, greener mining and recycling practices for the entire tech sector, the researchers state.

“Biology manages to differentiate rare earths from all the other metals out there — and now, we can see how it even differentiates between the rare earths it finds useful and the ones it doesn’t,” said Joseph Cotruvo Jr., associate professor of chemistry at Penn State and lead author on a paper about the discovery published today (May 31) in the journal Nature. “We’re showing how we can adapt these approaches for rare earth recovery and separation.”

Rare earth elements, which include the lanthanide metals, are in fact relatively abundant, Cotruvo explained, but they are what mineralogists call “dispersed,” meaning they’re mostly scattered throughout the planet in low concentrations.

“If you can harvest rare earths from devices that we already have, then we may not be so reliant on mining it in the first place,” Cotruvo said. However, he added that regardless of source, the challenge of separating one rare earth from another to get a pure substance remains.

“Whether you are mining the metals from rock or from devices, you are still going to need to perform the separation. Our method, in theory, is applicable for any way in which rare earths are harvested,” he said.

All the same — and completely different

In simple terms, rare earths are 15 elements on the periodic table — the lanthanides, with atomic numbers 57 to 71 — and two other elements with similar properties that are often grouped with them. The metals behave similarly chemically, have similar sizes, and, for those reasons, they often are found together in the Earth’s crust. However, each one has distinct applications in technologies.

Conventional rare earth separation practices require using large amounts of toxic chemicals like kerosene and phosphonates, similar to chemicals that are commonly used in insecticides, herbicides and flame retardants, Cotruvo explained. The separation process requires dozens or even hundreds of steps, using these highly toxic chemicals, to achieve high-purity individual rare earth oxides.

“There is getting them out of the rock, which is one part of the problem, but one for which many solutions exist,” Cotruvo said. “But you run into a second problem once they are out, because you need to separate multiple rare earths from one another. This is the biggest and most interesting challenge, discriminating between the individual rare earths, because they are so alike. We’ve taken a natural protein, which we call lanmodulin or LanM, and engineered it to do just that.”

Learning from nature

Cotruvo and his lab turned to nature to find an alternative to the conventional solvent-based separation process, because biology has already been harvesting and harnessing the power of rare earths for millennia, especially in a class of bacteria called “methylotrophs” that often are found on plant leaves and in soil and water and play an important role in how carbon moves through the environment.

Six years ago, the lab isolated lanmodulin from one of these bacteria, and showed that it was unmatched — over 100 million times better — in its ability to bind lanthanides over common metals like calcium. Through subsequent work they showed that it was able to purify rare earths as a group from dozens of other metals in mixtures that were too complex for traditional rare earth extraction methods. However, the protein was less good at discriminating between the individual rare earths.

Cotruvo explained that for the new study detailed in Nature, the team identified hundreds of other natural proteins that looked roughly like the first lanmodulin but homed in on one that was different enough — 70% different — that they suspected it would have some distinct properties. This protein is found naturally in a bacterium (Hansschlegelia quercus) isolated from English oak buds.

The researchers found that the lanmodulin from this bacterium exhibited strong capabilities to differentiate between rare earths. Their studies indicated that this differentiation came from an ability of the protein to dimerize and perform a kind of handshake. When the protein binds one of the lighter lanthanides, like neodymium, the handshake (dimer) is strong. By contrast, when the protein binds to a heavier lanthanide, like dysprosium, the handshake is much weaker, such that the protein favors the monomer form.

“This was surprising because these metals are very similar in size,” Cotruvo said. “This protein has the ability to differentiate at a scale that is unimaginable to most of us — a few trillionths of a meter, a difference that is less than a tenth of the diameter of an atom.”

Fine-tuning rare earth separations

To visualize the process at such a small scale, the researchers teamed up with Amie Boal, Penn State professor of chemistry, biochemistry and molecular biology, who is a co-author on the paper. Boal’s lab specializes in a technique called X-ray crystallography, which allows for high-resolution molecular imaging.

The researchers determined that the protein’s ability to dimerize dependent on the lanthanide to which it was bound came down to a single amino acid — 1% of the whole protein — that occupied a different position with lanthanum (which, like neodymium, is a light lanthanide) than with dysprosium.

Because this amino acid is part of a network of interconnected amino acids at the interface with the other monomer, this shift altered how the two protein units interacted. When an amino acid that is a key player in this network was removed, the protein was much less sensitive to rare earth identity and size. The findings revealed a new, natural principle for fine-tuning rare earth separations, based on propagation of miniscule differences at the rare earth binding site to the dimer interface.

Using this knowledge, their collaborators at Lawrence Livermore National Laboratory showed that the protein could be tethered to small beads in a column, and that it could separate the most important components of permanent magnets, neodymium and dysprosium, in a single step, at room temperature and without any organic solvents.

“While we are by no means the first scientists to recognize that metal-sensitive dimerization could be a way of separating very similar metals, mostly with synthetic molecules,” Cotruvo said, “this is the first time that this phenomenon has been observed in nature with the lanthanides. This is basic science with applied outcomes. We’re revealing what nature is doing and it’s teaching us what we can do better as chemists.”

Cotruvo believes that the concept of binding rare earths at a molecular interface, such that dimerization is dependent on the exact size of the metal ion, can be a powerful approach for accomplishing challenging separations.

“This is the tip of the iceberg,” he said. “With further optimization of this phenomenon, the toughest problem of all — efficient separation of rare earths that are right next to each other on the periodic table — may be within reach.”

A patent application was filed by Penn State based on this work and the team is currently scaling up operations, fine-tuning and streamlining the protein with the goal of commercializing the process.

Other Penn State co-authors are Joseph Mattocks, Jonathan Jung, Chi-Yun Lin, Neela Yennawar, Emily Featherston and Timothy Hamilton. Ziye Dong, Christina Kang-Yun and Dan Park of the Lawrence Livermore National Laboratory also co-authored the paper.

The work was funded by the U.S. Department of Energy, the National Science Foundation, the National Institutes of Health, the Jane Coffin Childs Memorial Fund for Medical Research, and the Critical Materials Institute, an Energy Innovation Hub funded by the DOE, Office of Energy Efficiency and Renewable Energy, Advanced Materials and Manufacturing Technologies Office. Part of the work was performed under the auspices of the DOE by Lawrence Livermore National Laboratory.

Since its discovery by Roentgen in 1895, X-rays have been used everywhere, from medical examinations to security screenings in airports. Even Curiosity, NASA’s Mars rover, is equipped with an X-ray device to examine the materials composition of the rocks in Mars. An important usage of X-rays in science is to identify the type of materials in a sample. Over the years, the quantity of materials in a sample required for X-ray detection has been greatly reduced thanks to the development of synchrotron X-rays sources and new instruments. To date, the smallest amount one can X-ray a sample is in attogram, that is about 10,000 atoms or more. This is due to the X-ray signal produced by an atom being extremely weak so that the conventional X-ray detectors cannot be used to detect it. According to Hla, it is a long-standing dream of scientists to X-ray just one atom, which is now being realized by the research team led by him.

“Atoms can be routinely imaged with scanning probe microscopes, but without X-rays one cannot tell what they are made of. We can now detect exactly the type of a particular atom, one atom-at-a-time, and can simultaneously measure its chemical state,” explained Hla, who is also the director of the Nanoscale and Quantum Phenomena Institute at Ohio University. “Once we are able to do that, we can trace the materials down to ultimate limit of just one atom. This will have a great impact on environmental and medical sciences and maybe even find a cure that can have a huge impact for humankind. This discovery will transform the world.”

Their paper, published in the scientific journal Nature on May 31, 2023, and gracing the cover of the print version of the scientific journal on June 1, 2023, details how Hla and several other physicists and chemists, including Ph.D. students at OHIO, used a purpose-built synchrotron X-ray instrument at the XTIP beamline of Advanced Photon Source and the Center for Nanoscale Materials at Argonne National Laboratory.

For demonstration, the team chose an iron atom and a terbium atom, both inserted in respective molecular hosts. To detect X-ray signal of one atom, the research team supplemented conventional detectors in X-rays with a specialized detector made of a sharp metal tip positioned at extreme proximity to the sample to collect X-ray excited electrons — a technique known as synchrotron X-ray scanning tunneling microscopy or SX-STM. X-ray spectroscopy in SX-STM is triggered by photoabsorption of core level electrons, which constitutes elemental fingerprints and is effective in identifying the elemental type of the materials directly.

According to Hla, the spectrums are like fingerprints, each one being unique and able to detect exactly what it is.

“The technique used, and concept proven in this study, broke new ground in X-ray science and nanoscale studies,” said Tolulope Michael Ajayi, who is the first author of the paper and doing this work as part of his Ph.D. thesis. “More so, using X-rays to detect and characterize individual atoms could revolutionize research and give birth to new technologies in areas such as quantum information and the detection of trace elements in environmental and medical research, to name a few. This achievement also opens the road for advanced materials science instrumentation.”

For the last 12 years, Hla has been involved in the development of an SX-STM instrument and its measurement methods together with Volker Rose, a scientist at the Advanced Photon Source at Argonne National Laboratory.

“I have been able to successfully supervise four OHIO graduate students for their Ph.D. theses related to SX-STM method development over a 12-year period. We have come a long way to achieve the detection of a single atom X-ray signature,” Hla said.

Hla’s study is focused on nano and quantum sciences with a particular emphasis on understanding materials’ chemical and physical properties at the fundamental level — on an individual atom basis. In addition to achieving X-ray signature of one atom, the team’s key goal was to use this technique to investigate the environmental effect on a single rare-earth atom.

“We have detected the chemical states of individual atoms as well,” Hla explained. “By comparing the chemical states of an iron atom and a terbium atom inside respective molecular hosts, we find that the terbium atom, a rare-earth metal, is rather isolated and does not change its chemical state while the iron atom strongly interacts with its surrounding.”

Many rare-earth materials are used in everyday devices, such as cell phones, computers and televisions, to name a few, and are extremely important in creating and advancing technology. Through this discovery, scientists can now identify not only the type of element but its chemical state as well, which will allow them to better manipulate the atoms inside different materials hosts to meet the ever-changing needs in various fields. Moreover, they have also developed a new method called “X-ray excited resonance tunneling or X-ERT” that allows them to detect how orbitals of a single molecule orient on a material surface using synchrotron X-rays.

“This achievement connects synchrotron X-rays with quantum tunneling process to detect X-ray signature of an individual atom and opens many exciting research directions including the research on quantum and spin (magnetic) properties of just one atom using synchrotron X-rays,” Hla said.

In addition to Ajayi, several other OHIO graduate students including current Ph.D. students Sineth Premarathna in Physics and Xinyue Cheng in Chemistry, as well as Ph.D. in Physics alumni Sanjoy Sarkar, Shaoze Wang, Kyaw Zin Latt, Tomas Rojas, and Anh T. Ngo, currently an Associate Professor of Chemical Engineering at the University of Illinois-Chicago, were involved in this research. College of Arts and Sciences Roenigk Chair and Professor of Chemistry Eric Masson designed and synthesized the rare earth molecule used in this study.

Going forward, Hla and his research team will continue to use X-rays to detect properties of just one atom and find ways to further revolutionize their applications for use in gathering critical materials research and more.

Described as “groundbreaking” by a team of researchers at UC San Diego’s Scripps Institution of Oceanography, this previously unknown process accounts for between 7% to 25% of all the oxygen produced and carbon fixed in the ocean. When also considering photosynthesis occuring on land, researchers estimated that this mechanism could be responsible for generating up to 12% of the oxygen on the entire planet.

Scientists have long recognized the significance of phytoplankton — microscopic organisms that drift in aquatic environments — due to their ability to photosynthesize. These tiny oceanic algae form the base of the aquatic food web and are estimated to produce around 50% of the oxygen on Earth.

The new study, published May 31 in the journal Current Biology, identifies how a proton pumping enzyme (known as VHA) aids in global oxygen production and carbon fixation from phytoplankton.

“This study represents a breakthrough in our understanding of marine phytoplankton,” said lead author Daniel Yee, who conducted the research while a PhD student at Scripps Oceanography and currently serves as a joint postdoctoral researcher at the European Molecular Biology Laboratory and University of Grenoble Alpes in France. “Over millions of years of evolution, these small cells in the ocean carry out minute chemical reactions, in particular to produce this mechanism that enhances photosynthesis, that shaped the trajectory of life on this planet.”

Working closely with Scripps physiologist Martín Tresguerres, one of his co-advisors, and other collaborators at Scripps and the Lawrence Livermore National Laboratory, Yee unraveled the complex inner workings of a specific group of phytoplankton known as diatoms, which are single-celled algae famous for their ornamental cell walls made of silica.

Understanding the “proton pump” enzyme

Previous research in the Tresguerres Lab has worked to identify how VHA is used by a variety of organisms in processes critical to life in the oceans. This enzyme is found in nearly all forms of life, from humans to single-celled algae, and its basic role is to modify the pH level of the surrounding environment.

“We imagine proteins as Lego blocks,” explained Tresguerres, a study co-author. “The proteins always do the same thing, but depending on what other proteins they are paired with, they can achieve a vastly different function.”

In humans, the enzyme aids kidneys in regulating blood and urine functions. Giant clams use the enzyme to dissolve coral reefs, where they secrete an acid that bores holes in the reef to take shelter. Corals use the enzyme to promote photosynthesis by their symbiotic algae, while deep-sea worms known as Osedax use it to dissolve the bones of marine mammals, such as whales, so they can consume them. The enzyme is also present in the gills of sharks and rays, where it is part of a mechanism that regulates blood chemistry. And in fish eyes, the proton pump helps deliver oxygen that enhances vision.

Looking at this previous research, Yee wondered how the VHA enzyme was being used in phytoplankton. He set out to answer this question by combining high-tech microscopy techniques in the Tresguerres Lab and genetic tools developed in the lab of the late Scripps scientist Mark Hildebrand, who was a leading expert on diatoms and one of Yee’s co-advisors.

Using these tools, he was able to label the proton pump with a fluorescent green tag and precisely locate it around chloroplasts, which are known as “organelles” or specialized structures within diatom cells. The chloroplasts of diatoms are surrounded by an additional membrane compared to other algae, enveloping the space where carbon dioxide and light energy are converted into organic compounds and released as oxygen.

“We were able to generate these images that are showing the protein of interest and where it is inside of a cell with many membranes,” said Yee. “In combination with detailed experiments to quantify photosynthesis, we found that this protein is actually promoting photosynthesis by delivering more carbon dioxide, which is what the chloroplast uses to produce more complex carbon molecules, like sugars, while also producing more oxygen as a by-product.”

Connection to evolution

Once the underlying mechanism was established, the team was able to connect it to multiple aspects of evolution. Diatoms were derived from a symbiotic event between a protozoan and an algae around 250 million years ago that culminated into the fusing of the two organisms into one, known as symbiogenesis. The authors highlight that the process of one cell consuming another, known as phagocytosis, is widespread in nature. Phagocytosis relies on the proton pump to digest the cell that acts as the food source. However, in the case of diatoms, something special occurred in which the cell that was eaten didn’t get fully digested.

“Instead of one cell digesting the other, the acidification driven by the proton pump of the predator ended up promoting photosynthesis by the ingested prey,” said Tresguerres. “Over evolutionary time, these two separate organisms fused into one, for what we now call diatoms.”

Not all algae have this mechanism, so the authors think that this proton pump has given diatoms an advantage in photosynthesis. They also note that when diatoms originated 250 million years ago, there was a big increase in oxygen in the atmosphere, and the newly discovered mechanism in algae might have played a role in that.

The majority of fossil fuels extracted from the ground are believed to have originated from the transformation of biomass that sank to the ocean floor, including diatoms, over millions of years, resulting in the formation of oil reserves. The researchers are hopeful that their study can provide inspiration for biotechnological approaches to improve photosynthesis, carbon sequestration, and biodiesel production. Additionally, they think it will contribute to a better understanding of global biogeochemical cycles, ecological interactions, and the impacts of environmental fluctuations, such as climate change.

“This is one of the most exciting studies in the field of symbiosis in the past decades and it will have a large impact on future research worldwide,” said Tresguerres.

Additional co-authors include Raffaela Abbriano, Bethany Shimasaki, Maria Vernet, Greg Mitchell, and the late Mark Hildebrand of Scripps Oceanography; Ty Samo, Xavier Mayali, and Peter Weber of the Lawrence Livermore National Laboratory; and Johan Decelle of University of Grenoble Alpes.

The authors did not receive any funding for this study. Yee’s doctoral studies at Scripps Oceanography were supported by the Scripps Fellowship, the NIH training grant, and the Ralph Lewin Graduate Fellowship. Funds by UC San Diego’s Arthur M. and Kate E. Tode Research Endowment in Marine Biological Sciences supported the purchase of a microscope that was essential for the research.