Tech

Per- and polyfluoroalkyl substances (PFAS) are used in a wide range of consumer products, from pizza boxes to carpets to non-stick cookware. Therefore, it's not surprising that these water- and stain-repelling substances are ubiquitous in the environment. Now, researchers report in Environmental Science & Technology Letters that cats and dogs excrete some PFAS in their feces at levels that suggest exposures above the minimum risk level, which could also have implications for the pets' owners.

Kurunthachalam Kannan and colleagues measured 15 different PFAS in 78 samples of cat and dog feces. Using high-performance liquid chromatography and tandem mass spectrometry, the researchers detected 13 different PFAS in the samples. The most abundant compounds in both cats and dogs were longer-chain perfluorocarboxylic acids. Based on these data, the researchers estimated PFAS exposure levels for the pets. They found that for three compounds (perfluorooctanoic acid, PFOA; perfluorononanoic acid, PFNA; and perfluorooctanesulfonic acid, PFOS) and for total PFAS, estimated exposure levels were above the minimal risk levels set by the U.S. Agency for Toxic Substances and Disease Registry. Because pets share homes with people, they could be used to monitor human exposure to PFAS, the researchers say.

In older adults with abdominal obesity (excess belly fat), sustained elevations of blood sugar were linked to a higher likelihood of experiencing cognitive decline. In older adults without abdominal obesity, the hormone adiponectin appeared to be a likely risk factor for cognitive decline.

The study, which is published in the Journal of the American Geriatrics Society, included 478 individuals aged 65 years or older who were examined annually for 10 years, with funding from the National Institute on Aging.

The findings--which were only observed among those younger than 87 to 88 years old--may eventually point to different strategies for preventing cognitive decline in different groups of older adults.

"This was population-level research, and the next steps should be in-depth clinical and laboratory studies to fully understand the biological mechanisms underlying the associations that we observed," said lead author Mary Ganguli, MD, MPH, of the University of Pittsburgh School of Medicine.

A recent analysis published in the American Journal of Transplantation estimates that for the average US patient who has undergone kidney transplantation, failure of the transplanted organ (graft failure) will impose additional medical costs of $78,079 and a loss of 1.66 quality-adjusted life years. (One quality-adjusted life year is equal to one year of life in perfect health.)

The authors note that given 17,644 kidney transplants in 2017, the total incremental lifetime medical costs associated with graft failure is $1.38 billion and the total quality-adjusted life years lost is 29,289.

The results indicate that efforts to reduce the incidence of kidney transplant failure or to mitigate its impact are urgently needed. "While short-term outcomes for kidney transplant recipients have improved, long-term outcomes have not: ten-year graft failure rates remain higher than 50%," said corresponding author Rebecca Kee, of Precision Health Economics. "This calls for long-term investment in novel technologies to improve graft survival, given that graft failure is associated with substantial costs and impacts on quality and length of life."

Treating obesity in children and adolescents improves self-esteem and body image, according to an analysis of all relevant studies published to date. The analysis, which is published in Pediatric Obesity, included 64 studies.

Losing weight appeared important for achieving improvements in body image but not self-esteem.

"Our findings are encouraging as they show that pediatric obesity treatment can improve psychological as well as weight-related outcomes," said lead author Megan Gow, PhD, of the University of Sydney, in Australia.

USC scientists have developed a new tool to peer more deeply and clearly into living things, a visual advantage that saves time and helps advance medical cures.

It's the sort of foundational science that can be used to develop better diagnostics and treatments, including detecting lung cancer or damage from pollutants. The technology is versatile enough it could become a smartphone app for use in remote medicine, food safety or counterfeit currency detection, said Francesco Cutrale, lead author of the study and research assistant professor of biomedical engineering at the USC Viterbi School of Engineering.

Scientists affiliated with the USC Michelson Center for Convergent Bioscience have been working on the technology for the past few years. Their findings are published today in Nature Communications.

The technique focuses, literally, on the building blocks of biology. When biologists look deeply into a living thing -- a cell, a fish, a person -- it's not always clear what's going on. Cells and proteins are deeply intertwined across tissues, leaving lots of questions about the interactions between components. The first step to curing disease is seeing the problem clearly, and that's not always been easy.

How this new imaging technique works

To solve the problem, researchers have been relying on a technique called fluorescence hyperspectral imaging (fHSI). It's a method that can differentiate colors across a spectrum, tag molecules so they can be followed, and produce vividly colored images of an organism's insides.

But the advantages that fHSI offers come with limitations. It doesn't necessarily reveal the full-color spectrum. It requires lots of data, due to the complexity of biological systems, so it takes a long time to gather and process the images. Many time-consuming calculations are also involved, which is a big drawback because experiments work better when they can be done in real time.

To solve those problems, the USC researchers developed a new method called spectrally encoded enhanced representations (SEER). It provides greater clarity and works up to 67 times faster and at 2.7 times greater definition than present techniques.

It relies on mathematical computations to parse the data faster. It can process vibrant fluorescent tags across the full spectrum of colors for more detail. And it uses much less computer memory storage, even more important with the explosion of big data research behind modern convergent bioscience research. According to the study, SEER is a "fast, intuitive and mathematical way" to interpret images as they are collected and processed.

"There is a number of scenarios where this after-the-fact analysis, while powerful, would be too late in experimental or medical decision-making," Cutrale said. "There is a gap between acquisition and analysis of the hyperspectral data, where scientists and doctors are unaware of the information contained in the experiment. SEER is designed to fill this gap."

From detecting lung cancer to potential mobile phone app

SEER's first application will be in the medical and research field. The versatile algorithm, first authored by Wen Shi and Daniel Koo at the Translational Imaging Center of USC, will be used for detecting early stages of lung disease and potential damage from pollutants in patients in a collaboration with doctors at Children's Hospital Los Angeles. Also, scientists in the life sciences field have started adopting SEER in their experimental pipelines in an effort to further improve efficiency.

Improvements in imaging technologies can also reach the consumer level, so it's likely that technologies such as fHSI and SEER could be installed on mobile phones to provide powerful visualization tools.

The Michelson Center brings together a diverse network of premier scientists and engineers from the USC Dornsife College of Letters, Arts and Sciences, the USC Viterbi School of Engineering and the Keck School of Medicine of USC under one roof, thanks to a generous $50 million gift from orthopedic spinal surgeon, inventor and philanthropist Gary K. Michelson and his wife, Alya Michelson.

Before the United States 1970 Clean Air Act, rainfall all over the country was acidic. As precipitation would fall from the sky, it would mix with gases from industrial plants, emissions from cars, and especially coal and fossil fuel consumption. That caused the water to become acidic - also called "acid rain."

Besides the air pollution hurting plants and humans, this acid rain also hurt our soils. Even dry deposits of these acidic emissions could be hurtful to humans, plants, soil and water. Acidic soil can bind nutrients so that plants can't get them. It can hurt the microbes in soil, as well as plants.

One odd "helpful" thing acid rain did, though, was to provide a few nutrients to the soil. The sulfur in the acid rain - in the form of sulfates - actually provided nutrition to plants. However, the benefit was negligible, and the overall effects of pollution required regulation. Occasionally, cities like Los Angeles will still experience "smog." The incidents are even more common in China and India, where little regulation is in effect.

Jennifer Knoepp, with the US Forest Service, has been studying how the reduction of air pollution and acid rain is affecting forests in the southern Appalachian Mountains. Her interest is to see how soils are recovering as our air gets cleaner.

Both the 1970 Clean Air Act and 1990 Amendment regulated emissions across the United States, resulting in improved air and water quality. But what about the soil - the "skin" of the earth - that provides for food and shelter and is home to the world's largest biodiversity?

"We have found significant movement of sulfate from the soils over time," says Knoepp. "Sulfate is moving out of the surface soils and into the subsoil. In addition, the streams in our study site show improved water quality. However, soils and streams still exhibit chemical imbalances. This suggests recovery from decades of acid rain is a long-term process."

To evaluate the soils and water, researchers sampled 24 high elevation spruce-fir forest sites and two watersheds in the southern Appalachians. The sites represent a region in the southeastern U.S. with high gradients in elevation and precipitation, as well as high biodiversity.

The research area includes sites within the Great Smoky Mountain National Park and the southern end of the Blue Ridge Parkway. Both are major tourist and outdoor recreation destinations.

Recent soil collections were compared to archived soil samples from the 80s and 90s. Sample archives are essential to long-term research. They provide the ability to conduct tests not planned during an original experimental design.

The research team analyzed both the newly collected and archived samples for "extractable sulfate." All data were used to determine the long-term response of southern Appalachian forests to changes in sulfate deposition that occurred after the implementation of the Clean Air Act Amendment in 1990.

Data show that sulfate in precipitation and streams declined after implementation of the Clean Air Act Amendment. They also show that completely reversible sulfate has declined in surface soils. Sub-surface soils show either no change or an increase in partially reversible sulfate.

Diamond is prized by scientists and jewellers alike, largely for a range of extraordinary properties including exceptional hardness. Now a team of Australian scientists has discovered diamond can be bent and deformed, at the nanoscale at least.

The discovery opens up a range of possibilities for the design and engineering of new nanoscale devices in sensing, defence and energy storage but also shows the challenges that lie ahead for future nanotechnologies, the researchers say.

Carbon-based nanomaterials, such as diamond, were of particular scientific and technological interest because, "in their natural form, their mechanical properties could be very different from those at the micro and nanoscale", said the lead author of the study, published in Advanced Materials, PhD student Blake Regan from the University of Technology Sydney (UTS).

"Diamond is the frontrunner for emerging applications in nanophotonics, microelectrical mechanical systems and radiation shielding. This means a diverse range of applications in medical imaging, temperature sensing and quantum information processing and communication.

"It also means we need to know how these materials behave at the nanoscale - how they bend, deform, change state, crack. And we haven't had this information for single-crystal diamond," Regan said.

The team, which included scientists from Curtin University and Sydney University, worked with diamond nanoneedles, approximately 20nm in length, or 10,000 times smaller than a human hair. The nanoparticles were subjected to an electric field force from a scanning electron microscope. By using this unique, non-destructive and reversible technique, the researchers were able to demonstrate that the nanoneedles, also known as diamond nanopillars, could be bent in the middle to 90 degrees without fracturing.

As well as this elastic deformation, the researchers observed a new form of plastic deformation when the nanopillar dimensions and crystallographic orientation of the diamond occurred together in a particular way.

Chief Investigator UTS Professor Igor Aharonovich said the result was the unexpected emergence of a new state of carbon (termed 08-carbon) and demonstrated the "unprecedented mechanical behaviour of diamond".

"These are very important insights into the dynamics of how nanostructured materials distort and bend and how altering the parameters of a nanostructure can alter any of its physical properties from mechanical to magnetic to optical. Unlike many other hypothetical phases of carbon, 08-carbon appears spontaneously under strain with the diamond-like bonds progressively breaking in a zipper-like manner, transforming a large region from diamond into 08-carbon.

"The potential applications of nanotechnology are quite diverse. Our findings will support the design and engineering of new devices in applications such as super-capacitors or optical filters or even air filtration," he said.

The first hours of a lithium-ion battery's life largely determine just how well it will perform. In those moments, a set of molecules self-assembles into a structure inside the battery that will affect the battery for years to come.

This component, known as the solid-electrolyte interphase or SEI, has the crucial job of blocking some particles while allowing others to pass, like a tavern bouncer rejecting undesirables while allowing in the glitterati. The structure has been an enigma for scientists who have studied it for decades. Researchers have tapped multiple techniques to learn more but never -- until now -- had they witnessed its creation at a molecular level.

Knowing more about the SEI is a crucial step on the road to creating more energetic, longer-lasting and safer lithium-ion batteries.

The work published Jan. 27 in Nature Nanotechnology was performed by an international team of scientists led by researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory and the U.S. Army Research Laboratory. Corresponding authors include Zihua Zhu, Chongmin Wang and Zhijie Xu of PNNL and Kang Xu of the U.S. Army Research Laboratory.

Why lithium-ion batteries work at all: the SEI

The solid-electrolyte interphase is a very thin film of material that doesn't exist when a battery is first built. Only when the battery is charged for the very first time do molecules aggregate and electrochemically react to form the structure, which acts as a gateway allowing lithium ions to pass back and forth between the anode and cathode. Crucially, the SEI forces electrons to take a detour, which keeps the battery operating and makes energy storage possible.

It's because of the SEI that we have lithium-ion batteries at all to power our cell phones, laptops and electric vehicles.

But scientists need to know more about this gateway structure. What factors separate the glitterati from the riffraff in a lithium-ion battery? What chemicals need to be included in the electrolyte, and in what concentrations, for the molecules to form themselves into the most useful SEI structures so they don't continually sop up molecules from the electrolyte, hurting battery performance?

Scientists work with a variety of ingredients, predicting how they will combine to create the best structure. But without more knowledge about how the solid-electrolyte interphase is created, scientists are like chefs juggling ingredients, working with cookbooks that are only partially written.

Exploring lithium-ion batteries with new technology

To help scientists better understand the SEI more, the team used PNNL's patented technology to analyze the structure as it was created. Scientists used an energetic ion beam to tunnel into a just-forming SEI in an operating battery, sending some of the material airborne and capturing it for analysis while relying on surface tension to help contain the liquid electrolyte. Then the team analyzed the SEI components using a mass spectrometer.

The patented approach, known as in situ liquid secondary ion mass spectrometry or liquid SIMS, allowed the team to get an unprecedented look at the SEI as it formed and sidestep problems presented by a working lithium-ion battery. The technology was created by a team led by Zhu, building on previous SIMS work by PNNL colleague Xiao-Ying Yu.

"Our technology gives us a solid scientific understanding of the molecular activity in this complex structure," said Zhu. "The findings could potentially help others tailor the chemistry of the electrolyte and electrodes to make better batteries."

U.S. Army and PNNL researchers collaborate

The PNNL team connected with Kang Xu, a research fellow with the U.S. Army Research Laboratory and an expert on electrolyte and the SEI, and together they tackled the question.

The scientists confirmed what researchers have suspected -- that the SEI is composed of two layers. But the team went much further, specifying the precise chemical make-up of each layer and determining the chemical steps that occur in a battery to bring about the structure.

The team found that one layer of the structure, next to the anode, is thin but dense; this is the layer that repels electrons but allows lithium ions to pass through. The outer layer, right next to the electrolyte, is thicker and mediates interactions between the liquid and the rest of the SEI. The inner layer is a bit harder and the outer later is more liquidy, a little bit like the difference between undercooked and overcooked oatmeal.

The role of lithium fluoride

One result of the study is a better understanding of the role of lithium fluoride in the electrolyte used in lithium-ion batteries. Several researchers, including Kang Xu, have shown that batteries with SEIs richer in lithium fluoride perform better. The team showed how lithium fluoride becomes part of the inner layer of the SEI, and the findings offer clues about how to incorporate more fluorine into the structure.

"With this technique, you learn not only what molecules are present but also how they're structured," Wang says. "That's the beauty of this technology."

The PNNL portion of the research published in Nature Nanotechnology was funded by PNNL, DOE's Office of Energy Efficiency and Renewable Energy's Vehicle Technologies Office, and the U.S.-Germany Cooperation on Energy Storage. Kang Xu's work was funded by DOE's Office of Science Joint Center for Energy Storage Research. The liquid SIMS analysis was done at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science user facility located at PNNL.

In addition to Xu, Wang and Zhu, PNNL authors include Yufan Zhou, Mao Su, Xiafei Yu, Yanyan Zhang, Jun-Gang Wang, Xiaodi Ren, Ruiguo Cao, Wu Xu, Donald R. Baer and Yingge Du.

The power conversion efficiencies of organic solar cells (OSCs) based on blends of electron donor (D) and acceptor (A) semiconducting materials now exceed 16%. However, it is still lower than that of highly efficient inorganic SCs such as GaAs and perovskite. The charge generation efficiency in OSCs nowadays is nearly 100%, thus reducing the energy loss in output voltage is critically important for further enhancing the efficiency of OSCs.

Group of Assistant Professor Seiichiro Izawa and Professor Masahiro Hiramoto at Institute for Molecular Science and Professor Masaki Takahashi and Assistant Professor Keisuke Fujimoto at Shizuoka University in Japan report that regioselective bay-functionalization of perylene derivatives and the use of the synthesized PDI as an acceptor material reduces the open-circuit voltage loss in OSCs. PDI, a promising candidate as a superior non-fullerene acceptor material for OSCs, has attracted tremendous attention due to the highly efficient charge-carrier properties. However, it has been still difficult to synthesize custom-designed PDIs with high efficiency and desired regioselectivity. Reserchers developed regioselective bay-functionalization of PDI by using their original synthetic protocol of highly controllable monobromination of peryrene tetracarboxylate. The bay functionalization by electron donating groups lifted LUMO level of synthesized tetrasubstituted PDI (Fig. 1a). The use of the synthesized compound as an acceptor material of OSC increased open-circuit voltage as 0.25 V than non-substituted PDI (Fig. 1b). The origin of the high VOC was that bay-functionalization liftes LUMO level, leading to the reduction of the energy offset for charge separation and non-radiative recombination loss that is the most important topic in OSC field nowadays. The results will open up new aveneues for future development of potential PDI-based acceptor materials through the tailor-made synthesis of bay-functionalized PDIs for efficient OSCs.

In early September 2019, an Asian hornet (Vespa velutina nigrithorax) was collected alive in Hamburg, Germany, representing the northernmost find of the species so far in Europe and indicating its further spread to the north. The paper by the research group from Hamburg, which also serves to update the occurrence of the dangerous invader, was published in the open access journal Evolutionary Systematics.

Known to prey on many insects, including honey bees and other beneficiary species, the Asian hornet, which had already invaded parts of Southern and Central Europe, is a potential threat to apiculture and even to ecosystems.

The first specimen was captured in south-western France in 2005 and started to spread quickly. Over the next years, it invaded large parts of France and regions of Spain, Portugal, Belgium, Italy, the Netherlands, Great Britain and south-western parts of Germany. The estimated invasion speed for France has been estimated at around 78 km/year, but in reality, the species spread might be occurring much faster due to anthropogenic factors.

It's not yet clear if the collected Asian hornet belonged to an already settled population or it's rather the first record of a new invasion. Nevertheless, considering the fast invasion speed of the species and its relatively high climatic tolerance, it's quite possible that it had reached Hamburg on natural routes and now reproduces there.

Even though other models suggest that the Hamburg area is not suitable for the species today, the new find might be a sign that the Asian hornet has begun spreading at a speed above that previously known and even in climatically less favourable regions.

"Therefore, the current find needs to be taken seriously, no matter if it is only a single specimen or a member of an established population", shares the lead researcher Martin Husemann from Centrum für Naturkunde, University of Hamburg.

Invasive species are one of the great challenges in the modern world. Their occurrence can be considered as one of the key important ecological and evolutionary drivers.

For decades, carbon nanotubes held great promise of developments in the field of electronics and more. But one drawback to realizing these innovations has been the difficulty of incorporating additional materials into nanotubes. For the first time, researchers have grown crystals of various materials uniformly onto the surface of carbon nanotubes. They hope these modified structures will exhibit functions useful in electronic, chemical or other applications.

We all know that as technology progresses, devices become ever smaller and more feature laden. Such advancements are possible due to the continued work of scientists who explore new ways of coaxing materials to perform useful functions. One area researchers eagerly investigate is the function of flat two-dimensional (2D) crystals, each just one molecule thick. These are arranged in layers to create structures called Van der Waals heterostructures (vdWs).

"Many interesting phenomena have been seen in 2D vdWs and new kinds of electronic and optical components have been proposed as a result," said Professor Shigeo Maruyama. "However, we wondered whether it's possible to create spatially compact one-dimensional (1D) vdWs and what kinds of useful and unique properties these nanotube structures may have."

It turns out 1D vdWs are possible to fabricate, but it's far from easy. Maruyama, Associate Professor Rong Xiang and their team first created some pure carbon (C) nanotubes, which in itself is still a relatively new and difficult process. These were placed in a high-temperature atmosphere containing boron nitride (BN), which binds to the surface of the nanotube to form a uniform and continuous layer or crystal. A similar process then adds a third layer to this tube in the form of molybdenum disulfide (MoS2). When tube structures encapsulate one another like this it's called a coaxial structure, as multiple 1D shapes share an axis of orientation.

"At that time, the yield of this structure was still extremely low. I spent one full day at the controls of a transmission electron microscope probing the sample," explained Xiang. "In the afternoon when I was almost giving up, I found one of our coaxial nanotubes. Then a few minutes later, I found a second one! With two observations, I become fully confident that MoS2 based 1D vdWs can exist."

1D vdWs are an entirely new class of material and its properties have not yet been studied. But Maruyama, Xiang and their team are hopeful that these interesting structures may find use in applications such as flexible electronics, lasers, solar energy conversion, electrocatalytic water splitting (to produce hydrogen), photoelectric devices and more.

Tsukuba, Japan - If older drivers with cognitive impairment are no longer permitted behind the wheel then accident rates should fall. That seems like common sense, but it seems the logic isn't so simple. Since 2009, when Japan added cognitive tests to its license renewal process for those aged 75+, traffic injuries have actually increased.

It turns out, when older drivers lose their licenses, they often have to resort to bicycling or walking to get around. They become what's known as unprotected road users. A new study by researchers centered at the University of Tsukuba in Japan found increased traffic injuries among such older people, who lack the protection of a motor vehicle. The findings were published in the journal Accident Analysis and Prevention.

Motor vehicle collisions are increasing among older drivers; this has triggered stricter licensing rules. Cognitive tests in Japan aim to identify drivers with possible dementia and require that they see a physician. Other countries such as Denmark and Canada have introduced similar tests. However, the overall success of such programs remains unclear.

"Some studies found increased injury rates as older drivers were forced into a modal shift from driving to walking or biking," study first author Professor Masao Ichikawa says. "We wanted to see if this was true in Japan, and we wanted a more accurate picture. Rather than just look at pre- and post-test numbers, we used interrupted time-series analysis, which offsets factors that may have confounded the results over the years."

Using reliable national data, they found significant increases in traffic deaths and injuries among unprotected road users aged 75 and up in the period after this same age group became subject to testing.

The increases generally occurred at a later age in men. The researchers suggested this may be because women are more anxious about their driving skills and give up their licenses earlier. The study did, however, find decreases in deaths and injuries for motor vehicle passengers aged 75-79 after cognitive tests began. This may owe to friends and family being more reluctant to ride with drivers after seeing their discouraging test results.

"Our findings suggest that Japan's licensing policies may not adequately consider the dangers facing those who become unprotected when they must start walking or biking after losing their license," Professor Ichikawa says.

The study implies a need to reconsider how cognitive testing is implemented. While the tests aim to remove potentially dangerous drivers from the roads, older people's loss of a main mode of transport may expose them to new risks.

Scientists at the University of California San Diego have a much clearer idea thanks to the evolution of an advanced imaging system designed to record ultra-precise brain activities in flies.

Called "Flyception" when it was announced in 2016 as a system that could record freely walking flies, the new "Flyception2" employs a more advanced tracking and recording system that allows flies to move about uninhibited, allowing researchers to study brain activities during intricate behaviors.

The technology, which the researchers say has produced the first-ever picture of what happens in the brain during mating in any organism, is described in a paper published in Nature Communications.

"This technology has made it possible to record the animal while it's moving around completely untethered and unfettered in any sense," said Ralph Greenspan, a professor in the Division of Biological Sciences and Department of Cognitive Science, and associate director of the Kavli Institute for Brain and Mind (KIBM). "The strength of the system is that it gives us real-time information of what the cells in the brain are doing and an understanding of social behaviors."

Developed by first-author Dhruv Grover and coauthor Takeo Katsuki, Flyception2 features a groundbreaking design in which researchers surgically implant a transparent window on the fly's head. Three markers set triangularly on the window allow them to record ultra-fast movements--a rate of 20 millimeters per second for flies--while they interact with other flies, with cameras that track the animal and record at 1,000 frames per second.

Flyception2 recordings have revealed unprecedented insights of brain activities. For example, neuroscientists have long known that brain nerve cells called P1 neurons are active during courtship. This was confirmed with Flyception2 data--as a male fly approached a female, P1 activity ramped up. But the scientists were surprised to see that P1 neurons in male flies subsequently turned off during sex. Rather, the data revealed that a neuron known as mAL, which is tied to a GABA neurotransmitter, is switched on during copulation.

"Only by using this system were we able to obtain the surprise finding that P1 neurons are inactive during copulation," said Grover. "My hypothesis is that as mAL neurons turn on, P1 neural activity goes down, suggesting a countervailing effect of mAL in opposing P1 activity."

The initial results are the first step in tracking and dissecting a range of behaviors that Flyception2 allows scientists to study. Observing the female fly brain during courtship and mating is an untapped area of study, the researchers say.

"We hope this kind of technical advancement, which can only be done at this point in the fruit fly, can start to forge the way for other organisms," said Greenspan. "Scientists are starting to be able to draw parallels between which parts of the brain appear to have evolved from the same precursors in invertebrates and in mammals. As people do more of those molecular studies, we will be able to make those parallels in more detail."

The University of Rochester research lab that recently used lasers to create unsinkable metallic structures has now demonstrated how the same technology could be used to create highly efficient solar power generators.

In a paper in Light: Science & Applications, the lab of Chunlei Guo, professor of optics also affiliated with Physics and the Material Sciences Program, describes using powerful femto-second laser pulses to etch metal surfaces with nanoscale structures that selectively absorb light only at the solar wavelengths, but not elsewhere.

A regular metal surface is shiny and highly reflective. Years ago, the Guo lab developed a black metal technology that turned shiny metals pitch black. "But to make a perfect solar absorber," Guo says, "We need more than a black metal and the result is this selective absorber."

This surface not only enhances the energy absorption from sunlight, but also reduces heat dissipation at other wavelengths, in effect, "making a perfect metallic solar absorber for the first time," Guo says. "We also demonstrate solar energy harnessing with a thermal electric generator device."

"This will be useful for any thermal solar energy absorber or harvesting device," particularly in places with abundant sunlight, he adds.

The work was funded by the Bill and Melinda Gates Foundation, the Army Research Office, and the National Science Foundation.

The researchers experimented with aluminum, copper, steel, and tungsten, and found that tungsten, commonly used as a thermal solar absorber, had the highest solar absorption efficiency when treated with the new nanoscale structures. This improved the efficiency of thermal electrical generation by 130 percent compared to untreated tungsten.

Co-authors include Sohail Jalil, Bo Lai, Mohamed Elkabbash, Jihua Zhang, Erik M. Garcell, and Subhash Singh of the Guo lab.

The lab has also used the femto-second laser etching technology to create superhydrophobic (water repellent) and superhydrophilic (water-attracting) metals. In November 2019, for example, Guo's lab reported creating metallic structures that do not sink no matter how often they are forced into water or how much it is damaged or punctured.

This new paper, however, expands upon the lab's initial work with femto-second laser etched black metal.

Prior to creating the water attracting and repellent metals, Guo and his assistant, Anatoliy Vorobyev, demonstrated the use of femto-second laser pulses to turn almost any metal pitch black. The surface structures created on the metal were incredibly effective at capturing incoming radiation, such as light. But they captured light over a broad range of wavelengths.

Subsequently, his team used a similar process to change the color of a range of metals to various colors, such as blue, golden, and gray, in addition to the black already achieved. The applications could include making color filters and optical spectral devices, a car factory using a single laser to produce cars of different colors; etching a full-color photograph of a family into the refrigerator door; or proposing with a gold engagement ring that matches the color of your fiancee's blue eyes.

The lab also used the initial black and colored metal technique to create a unique array of nano- and micro-scale structures on the surface of a regular tungsten filament, enabling a light bulb to glow more brightly at the same energy usage.

"We fired the laser beam right through the glass of the bulb and altered a patch on the filament. When we lit the bulb, we could actually see this one patch was clearly brighter than the rest of the filament," Guo said.

PROVIDENCE, R.I. [Brown University] -- A team of Brown University researchers has made substantial progress in an effort to create a new type of molecular data storage system.

In a study published in Nature Communications, the team stored a variety of image files -- a Picasso drawing, an image of the Egyptian god Anubis and others -- in arrays of mixtures containing custom-synthesized small molecules. In all, the researchers stored more than 200 kilobytes of data, which they say is the most stored to date using small molecules. That's not a lot of data compared to traditional means of storage, but it is significant progress in terms of small molecule storage, the researchers say.

"I think this is a substantial step forward," said Jacob Rosenstein, an assistant professor in Brown's School of Engineering and an author of the study. "The large numbers of unique small molecules, the amount of data we can store, and the reliability of the data readout shows real promise for scaling this up even further."

As the data universe continues to expand, much work is being done to find new and more compact means of storage. By encoding data in molecules, it may be possible to store the equivalent of terabytes of data in just a few millimeters of space. Most research on molecular storage has focused on long-chain polymers like DNA, which are well known carriers of biological data. But there are potential advantages to using small molecules as opposed to long polymers. Small molecules are potentially easier and cheaper to produce than synthetic DNA, and in theory have an even higher storage capacity.

The Brown research team, supported by a U.S. Defense Advanced Research Projects Agency (DARPA) grant led by chemistry professor Brenda Rubenstein, has been working to find ways of making small-molecule data storage feasible and scalable.

To store data, the team uses small metal plates arrayed with 1,500 tiny spots less than a millimeter in diameter. Each spot contains a mixture of molecules. The presence or absence of different molecules in each mixture indicate the digital data. The number of bits in each mixture can be as large as the library of distinct molecules available for mixing. The data can then be read out using a mass spectrometer, which can identify the molecules present in each well.

In a paper published last year, the Brown team showed that they could store image files in the kilobyte range using some common metabolites, the molecules that organisms use to regulate metabolism. For this new work, the researchers were able to vastly expand the size of their library -- and thereby the sizes of the files they could encode -- by synthesizing their own molecules.

The team made their molecules using Ugi reactions -- a technique often used in the pharmaceutical industry to quickly produce large numbers of different compounds. Ugi reactions combine four broad classes of reagents (an amine, an aldehyde or a ketone, a carboxylic acid, and an isocyanide) into one new molecule. By using different reagents from each class, the researchers could quickly produce a wide array of distinct molecules. For this work, the team used five different amines, five aldehydes, 12 carboxylic acids, and five isocyanides in different combinations to create 1,500 distinct compounds.

"The advantage here is the potential scalability of the library," Rubenstein said. "We use just 27 different components to make a 1,500-molecule library in one day. That means we don't have to go out and find 1,500 unique molecules."

From there, the team used sub-libraries of compounds to encode their images. A 32-compound library was used to store a binary image of the Egyptian god Anubis. A 575-compound library was used to encode a 0.88-megapixel Picasso drawing of a violin.

The large number of molecules available for the chemical libraries also enabled the researchers to explore alternate encoding schemes that made the readout of data more robust. While mass spectrometry is highly precise, it's not perfect. So as with any system used to store or transmit data, this system will need some form of error correction.

"The way we design the libraries and read out the data includes extra information that lets us correct some errors," said Brown graduate student Chris Arcadia, first author of the paper. "That helped us streamline the experimental workflow and still get accuracy rates as high as 99 percent."

There's still more work to be done to bring this idea up to a useful scale, the researchers say. But the ability to create large chemical libraries and use them for encoding ever larger files suggests the approach can indeed be scaled up.

"We're no longer limited by the size of our chemical library, which is really important," Rosenstein said. "That's the biggest step forward here. When we started this project a few years ago, we had some debates about whether something of this scale was even experimentally feasible. So it's really encouraging that we've been able to do this."