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    AI-based method for dating archeological remains

    By analyzing DNA with the help of artificial intelligence (AI), an international research team led by Lund University in Sweden has developed a method that can accurately date up to ten-thousand year-old human remains.
    Accurately dating ancient humans is key when mapping how people migrated during world history.
    The standard dating method since the 1950s has been radiocarbon dating. The method, which is based on the ratio between two different carbon isotopes, has revolutionized archaeology. However, the technology is not always completely reliable in terms of accuracy, making it complicated to map ancient people, how they moved and how they are related.
    In a new study published in Cell Reports Methods, a research team has developed a dating method that could be of great interest to archaeologists and paleognomicists.
    “Unreliable dating is a major problem, resulting in vague and contradictory results. Our method uses artificial intelligence to date genomes via their DNA with great accuracy, says Eran Elhaik, researcher in molecular cell biology at Lund University.
    The method is called Temporal Population Structure (TPS) and can be used to date genomes that are up to 10,000 years old. In the study, the research team analyzed approximately 5,000 human remains — from the Late Mesolithic period (10,000-8,000 BC) to modern times. All of the studied samples could be dated with a rarely seen accuracy.
    “We show that information about the period in which people lived is encoded in the genetic material. By figuring out how to interpret it and position it in time, we managed to date it with the help of AI,” says Eran Elhaik.
    The researchers do not expect TPS to eliminate radiocarbon dating but rather see the method as a complementary tool in the paleogeographic toolbox. The method can be used when there is uncertainty involving a radiocarbon dating result. One example is the famous human skull from Zlatý kůň in today’s Czech Republic, which could be anywhere between 15,000 and 34,000 years old.
    “Radiocarbon dating can be very unstable and is affected by the quality of the material being examined. Our method is based on DNA, which makes it very solid. Now we can seriously begin to trace the origins of ancient people and map their migration routes,” concludes Eran Elhaik.
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    Materials provided by Lund University. Note: Content may be edited for style and length. More

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    Smartphones make consumers prefer unique, tailored products

    Personalized wine lists. Tailored clothing options. Unique experiences just for you.
    The world is awash in products and services that promise to provide custom experiences to every consumer. And it turns out our smartphones are pushing us to unconsciously prefer just these kinds of customized options.
    A new study from the University of Florida has discovered that consumers gravitate toward customized, rare or special products when they are engrossed in their phones. The highly private and personalized feelings we have toward our phones seem to encourage us to express our unique selves more than if we buy products on a larger computer — or borrow some stranger’s phone.
    The findings suggest that companies should — and indeed might already — change what they offer to consumers depending on what device they are using. The smartphone’s activation of a self-expression mindset also likely alters a range of behaviors, such as how people respond to political polls on mobile devices.
    “When you use your phone, your authentic self is being expressed to a greater extent. That affects the options you seek and the attitudes you express,” said Aner Sela, a professor in UF’s Warrington College of Business and one of the authors of the study.
    Sela and his former doctoral student Camilla Song, now an assistant professor at City University of Hong Kong, published their findings Aug. 3 in the Journal of Marketing Research. More

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    Microscopic color converters move small laser-based devices closer to reality

    Lasers are everywhere. Devices that use them transmit information and enable the existence of long-distance communications and the internet; they aid doctors performing surgeries and engineers manufacturing advanced tools and technologies; and day-to-day, we encounter lasers as we scan our groceries and watch DVDs. “In the 60-some years since they were invented, lasers have absolutely transformed our lives,” said Giulio Cerullo, a nonlinear optics researcher at Politecnico di Milano in Italy.
    Today, with the help of new research from Cerullo and collaborators at Columbia University published in Nature Photonics, devices that use lasers are poised to become a whole lot smaller.
    Working in engineer James Schuck’s lab at Columbia, PhD student Xinyi Xu and postdoc Chiara Trovatello studied a 2D material called molybdenum disulfide (MoS2). They characterized how efficiently devices built from stacks of MoS2 less than one micron thick — that’s 100 times thinner than a human hair — convert light frequencies at telecom wavelengths to produce different colors.
    This new research is a first step toward replacing the standard materials used in today’s tunable lasers, which are measured in millimeters and centimeters, said Trovatello, who recently completed her PhD with Cerullo in Milan. “Nonlinear optics is currently a macroscopic world, but we want to make it microscopic,” she said.
    Lasers give off a special kind of coherent light, which means all the photons in the beam share the same frequency and thus, color. Lasers operate only at specific frequencies, but devices often need to be able to deploy different colors of laser light. For example, a green laser pointer is actually produced by an infrared laser that’s converted to a visible color by a macroscopic material. Researchers use nonlinear optical techniques to change the color of laser light, but conventionally used materials need to be relatively thick for color conversion to occur efficiently.
    MoS2 is one of the most studied examples of an emerging class of materials called transition metal dichalcogenides, which can be peeled into atomically thin layers. Single layers of MoS2 can convert light frequencies efficiently, but are actually too thin to be used to build devices. Larger crystals of MoS2, meanwhile, tend to be more stable in a non-color converting form. To fabricate the necessary crystals, known as 3R-MoS2, the team worked with the commercial 2D-material supplier HQ Graphene.
    With 3R-MoS2 in hand, Xu began peeling off samples of varying thickness to test how efficiently they converted the frequency of light. Right away, the results were spectacular. “Rarely in science do you start on a project that ends up working better than you expect — usually it’s the opposite. This was a rare, magical case,” remarked Schuck. Usually, special sensors are needed to register the light produced by a sample, and it takes some time for them to do so, explained Xu. “With 3R-MoS2, we could see the extremely large enhancement almost immediately,” he said. Notably, the team recorded these conversions at telecom wavelengths, a key feature for potential optical communications applications, such as delivering internet and television services.
    In a fortunate accident during one scan, Xu focused on a random edge of a crystal and saw fringes that suggested waveguide modes were present inside the material. Waveguide modes keep different color photons, which otherwise move at different speeds across the crystal, in sync, and can possibly be used to generate so-called entangled photons, a key component of quantum optics applications. The team handed their devices off to the lab of physicist Dmitri Basov, where his postdoc Fabian Mooshammer confirmed their hunch.
    Currently, the most popular crystal for waveguided conversion and generating entangled photons is lithium niobate, a hard and stiff material that needs to be fairly thick for achieving useful conversion efficiencies. 3R-MoS2 is equally efficient but 100 times smaller and flexible enough that it can be combined with silicon photonic platforms to create optical circuits on chips, following the trajectory of ever-smaller electronics.
    With this proof-of-concept result, the bottleneck toward real-life applications is large-scale production of 3R-MoS2 and high-throughput structuring of devices. There, the team says, industry will need to take over. With this work, they hope they’ve demonstrated the promise of 2D materials.
    “I’ve been working on nonlinear optics for more than thirty years now. Research is most often incremental, slowly building on what came before. It’s rare that you do something completely new with big potential,” said Cerullo. “I have a feeling that this new material could change the game.” More

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    Sea urchin skeletons’ splendid patterns may strengthen their structure

    Sea urchin skeletons may owe some of their strength to a common geometric design.

    Components of the skeletons of common sea urchins (Paracentrotus lividus) follow a similar pattern to that found in honeycombs and dragonfly wings, researchers report in the August Journal of the Royal Society Interface. Studying this recurring natural order could inspire the creation of strong yet lightweight new materials.

    Urchin skeletons display “an incredible diversity of structures at the microscale, varying from fully ordered to entirely chaotic,” says marine biologist and biomimetic consultant Valentina Perricone. These structures may help the animals maintain their shape when faced with predator attacks and environmental stresses.

    While using a scanning electron microscope to study urchin skeleton tubercules — sites where the spines attach that withstand strong mechanical forces — Perricone spotted “a curious regularity.” Tubercules seem to follow a type of common natural order called a Voronoi pattern, she and her colleagues found.

    This Voronoi pattern generated on a computer has an 82 percent match with the pattern found in sea urchin skeletons.V. Perricone

    Using math, a Voronoi pattern is created by a process that divides a region into polygon-shaped cells that are built around points within them called seeds (SN: 9/23/18). The cells follow the nearest neighbor rule: Every spot inside a cell is nearer to that cell’s seed than to any other seed. Also, the boundary that separates two cells is equidistant from both their seeds.

    A computer-generated Voronoi pattern had an 82 percent match with the pattern found in sea urchin skeletons. This arrangement, the team suspects, yields a strong yet lightweight skeletal structure. The pattern “can be interpreted as an evolutionary solution” that “optimizes the skeleton,” says Perricone, of the University of Campania “Luigi Vanvitelli” in Aversa, Italy.

    Urchins, dragonflies and bees aren’t the only beneficiaries of Voronoi architecture. “We are developing a library of bioinspired, Voronoi-based structures” that could “serve as lightweight and resistant solutions” for materials design, Perricone says. These, she hopes, could inspire new developments in materials science, aerospace, architecture and construction. More

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    Robotic kidney cancer surgery shows desirable outcomes in study

    Kidney cancer is not always confined to the kidney. In advanced cases, this cancer invades the body’s biggest vein, the inferior vena cava (IVC), which carries blood out of the kidneys back to the heart. Via the IVC, cancer may infiltrate the liver and heart. The Mays Cancer Center at The University of Texas Health Science Center at San Antonio (UT Health San Antonio) is one of the high-volume centers in the U.S. with surgical expertise in treating this serious problem. The Mays Cancer Center is San Antonio’s National Cancer Institute-designated Cancer Center.
    In a study featured on the cover of the Journal of Urology (Official Journal of the American Urological Association), researchers from the Mays Cancer Center and Department of Urology at UT Health San Antonio show that robotic IVC thrombectomy (removal of cancer from the inferior vena cava) is not inferior to standard open IVC thrombectomy and is a highly safe and effective alternative approach. The affected kidney is removed along with the tumor during surgery, which is performed at UT Health San Antonio’s clinical partner, University Hospital.
    Harshit Garg, MD, urologic oncology fellow in the Department of Urology, is first author of the study, and Dharam Kaushik, MD, urologic oncology fellowship program director, is the senior author. Kaushik is an associate professor and the Stanley and Sandra Rosenberg Endowed Chair in Urologic Research at UT Health San Antonio.
    The open surgery requires an incision that begins 2 inches below the ribcage and extends downward on both sides of the ribcage. “It looks like an inverted V,” Kaushik said. Next, organs that surround the IVC, such as the liver, are mobilized, and the IVC is clamped above and below the cancer. In this way, surgeons gain control of the inferior vena cava for cancer resection.
    “Open surgery has an excellent success rate, and most cases are performed in this manner,” Kaushik said. “But now, with the robotic approach, we can achieve similar results with smaller incisions. Therefore, we need to study the implications of utilizing this newer approach.”
    The study is a systematic review and meta-analysis of data from 28 studies that enrolled 1,375 patients at different medical centers. Of these patients, 439 had robotic IVC thrombectomy and 936 had open surgery. Kaushik and his team collaborated with Memorial Sloan Kettering Cancer Center, New York; Cedars-Sinai Medical Center, Los Angeles; and the University of Washington, Seattle, to perform this study.
    “We pulled the data together to make conclusions because, before this, only small studies from single institutions had been conducted to compare the IVC thrombectomy approaches,” Kaushik said.
    Findings
    The results are encouraging and indicate further study of robotic IVC thrombectomy is warranted. The robotic approach in comparison with open was associated with: Fewer blood transfusions: 18% of robotic patients required transfusions compared to 64% of open patients. Fewer complications: 5% of robotic patients experienced complications such as bleeding compared to 36.7% of open thrombectomy patients.These large, technically challenging surgeries last eight to 10 hours and involve a multidisciplinary team of vascular surgeons, cardiac surgeons, transplant surgeons and urologic oncology surgeons, Kaushik said.
    “This study is the largest meta-analysis analyzing the outcomes of robotic versus open IVC thrombectomy,” Kaushik said. “In more than 1,300 patients, we found that overall complications were lower with the robotic approach and the blood transfusion rate was lower with this approach.
    “That tells us there is more room for us to grow and refine this robotic procedure and to offer it to patients who are optimal candidates for it,” Kaushik said. “Optimal candidacy for a robotic surgery should be based on a surgeon’s robotic expertise, the extent and burden of the tumor, and the patient’s comorbid conditions. The open surgical approach remains the gold standard for achieving excellent surgical control.” More

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    Compost to computer: Bio-based materials used to salvage rare earth elements

    What do corncobs and tomato peels have to do with electronics? They both can be used to salvage valuable rare earth elements, like neodymium, from electronic waste. Penn State researchers used micro- and nanoparticles created from the organic materials to capture rare earth elements from aqueous solutions.
    Their findings, available online now, will also be published in the November issue of Chemical Engineering Journal.
    “Waste products like corncobs, wood pulp, cotton and tomato peels often end up in landfills or in compost,” said corresponding author Amir Sheikhi, assistant professor of chemical engineering. “We wanted to transform these waste products into micro- or nanoscale particles capable of extracting rare earth elements from electronic waste.”
    Rare earth metals are used to manufacture strong magnets used in motors for electric and hybrid cars, loudspeakers, headphones, computers, wind turbines, TV screens and more. However, mining these metals proves challenging and environmentally costly, according to Sheikhi, as large land areas are required to mine even small amounts of the metals. Instead, efforts have turned to recycling the metals from electronic waste items like old computers or circuit boards.
    The challenge lies in efficiently separating the metals from refuse, Sheikhi said.
    “Using the organic materials as a platform, we created highly functional micro- and nanoparticles that can attach to metals like neodymium and separate them from the fluid that surrounds them,” Sheikhi said. “Via electrostatic interactions, the negatively-charged micro- and nano-scale materials bind to positively-charged neodymium ions, separating them.”
    To prepare the experiment, Sheikhi’s team ground up tomato peel and corncob and cut wood pulp and cotton paper into small, thin pieces and soaked them in water. Then, they chemically reacted these materials in a controlled fashion to disintegrate them into three distinct fractions of functional materials: microproducts, nanoparticles and solubilized biopolymers. Adding the microproducts or nanoparticles to neodymium solutions triggered the separation process, resulting in the capture of neodymium samples. More

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    Extreme climate shifts long ago may have helped drive reptile evolution

    There’s nothing like a big mass extinction to open up ecological niches and clear out the competition, accelerating evolution for some lucky survivors. Or is there? A new study suggests that the rate of climate change may play just as large a role in speeding up evolution.

    The study focuses on reptile evolution across 57 million years — before, during and after the mass extinction at the end of the Permian Period (SN: 12/6/18). That extinction event, triggered by carbon dioxide pumped into the atmosphere and oceans through increased volcanic activity about 252 million years ago, knocked out a whopping 86 percent of Earth’s species. Yet reptiles recovered from the chaos relatively well. Their exploding diversity of species around that time has been widely regarded as a result of their slithering into newly available niches.

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    But rapid climate fluctuations were already taking place much earlier in the Permian, and so were surges of reptile diversification, researchers say. Analyzing fossils from 125 reptile species shows that bursts of evolutionary diversity in reptiles were tightly correlated with relatively rapid fluctuations in climate throughout the Permian and millions of years into the next geologic period, the Triassic, researchers report August 19 in Science Advances.

    Scientists’ understanding of evolution is expanding as they become more tuned into the connection between it and environmental change, says Jessica Whiteside, a geologist at the University of Southampton in England who works on mass extinctions but was not involved in the new work. “This study is bound to become an important part of that conversation.”

    To investigate reptile evolution, evolutionary paleobiologist Tiago Simões of Harvard University and colleagues precisely measured and scanned reptile fossils ranging from 294 million to 237 million years old. In all, the researchers examined 1,000 specimens at 50 research institutions in 20 countries.  For climate data, the team used an existing large database of sea surface temperatures based on oxygen isotope data, extending back 450 million years, published in 2021.

    By closely tracking changes in body and head size and shape in so many species, paired with that climate data, the researchers found that the faster the rate of climate change, the faster reptiles evolved. The fastest rate of reptile diversification did not occur at the end-Permian extinction, the team found, but several million years later in the Triassic, when climate change was at its most rapid and global temperatures witheringly hot. Ocean surface temperatures during this time soared to 40° Celsius, or 104⁰ Fahrenheit — about the temperature of a hot tub, says Simões.

    A few species did evolve less rapidly than their kin, Simões says. The difference? Size. For instance, reptiles with smaller body sizes are already preadapted to live in rapidly warming climates, he says. Due to their greater surface area to body ratio, “small-bodied reptiles can better exchange heat with their surrounding environment,” so stay relatively cooler than larger animals.

    “The smaller reptiles were basically being forced by natural selection to stay the same, while during that same period of time, the large reptiles were being told by natural selection ‘You need to change right away or you’re going to go extinct,’” Simões says.

    This phenomenon, called the Lilliput effect, is not a new proposal, Simões says, adding that it’s been well established in marine organisms. “But it’s the first time it’s been quantified in limbed vertebrates across this critical period in Earth’s history.”

    Simões and colleagues’ detailed work has refined the complex evolutionary tree for reptiles and their ancestors. But, for now, it’s unclear which played a bigger role in reptile evolution long ago — all those open ecological niches after the end-Permian mass extinction, or the dramatic climate fluctuations outside of the extinction event.

    “We cannot say which one was more important,” Simões says. “Without either one, the course of evolution in the Triassic and the rise of reptiles to global dominance in terrestrial ecosystems would have been quite different.”  More

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    Common, cheap ingredients can break down some ‘forever chemicals’

    There’s a new way to rip apart harmful “forever chemicals,” scientists say.

    Perfluoroalkyl and polyfluoroalkyl substances, also known as PFAS, are found in nonstick pans, water-repellent fabrics and food packaging and they are pervasive throughout the environment. They’re nicknamed forever chemicals for their ability to stick around and not break down. In part, that’s because PFAS have a super strong bond between their carbon and fluorine atoms (SN: 6/4/19). Now, using a bit of heat and two relatively common compounds, researchers have degraded one major type of forever chemical in the lab, the team reports in the Aug. 19 Science. The work could help pave the way for a process for breaking down certain forever chemicals commercially, for instance by treating wastewater.

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    “The fundamental knowledge of how the materials degrade is the single most important thing coming out of this study,” organic chemist William Dichtel said in an August 16 news conference.

    While some scientists have found relatively simple ways of breaking down select PFAS, most degradation methods require harsh, energy-intensive processes using intense pressure — in some cases over 22 megapascals — or extremely high temperatures — sometimes upwards of 1000⁰ Celsius — to break the chemical bonds (SN: 6/3/22).

    Dichtel, of Northwestern University in Evanston, Ill., and his team experimented with two substances found in nearly every chemistry lab cabinet: sodium hydroxide, also known as lye, and a solvent called dimethyl sulfoxide, or DMSO. The team worked specifically with a group of forever chemicals called PFCAs, which contain carboxylic acid and constitute a large percentage of all PFAS. Some of these kinds of forever chemicals are found in water-resistant clothes.

    When the team combined PFCAs with the lye and DMSO at 120⁰ C and with no extra pressure needed, the carboxylic acid fell off the chemical and became carbon dioxide in a process called decarboxylation. What happened next was unexpected, Dichtel said. Loss of the acid led to a process causing “the entire molecule to fall apart in a cascade of complex reactions.” This cascade involved steps that degraded the rest of the chemical into fluoride ions and smaller carbon-containing products, leaving behind virtually no harmful by-products.     .

    “It’s a neat method, it’s different from other ones that have been tried,” says Chris Sales, an environmental engineer at Drexel University in Philadelphia who was not involved in the study. “The biggest question is, how could this be adapted and scaled up?” Northwestern has filed a provisional patent on behalf of the researchers.

    Understanding this mechanism is just one step in undoing forever chemicals, Dichtel’s team said. And more research is needed: There are other classes of PFAS that require their own solutions. This process wouldn’t work to tackle PFAS out in the environment, because it requires a concentrated amount of the chemicals. But it could one day be used in wastewater treatment plants, where the pollutants could be filtered out of the water, concentrated and then broken down. More