Category: 7. Science

  • Impacts of ultrasonic osteotomy devices on bone regeneration and brain activity in a mouse model

    Impacts of ultrasonic osteotomy devices on bone regeneration and brain activity in a mouse model

    Primary findings

    This study aimed to investigate ​UOD-induced thermomechanical effects on bone microstructure and brain tissue preservation​ in neuro-spine surgery analogs. We found that the bone healing is comparable between UOD and HSB defects, as shown by micro-CT images. However, histological analyses revealed laminated-layered structural changes to the bone tissues adjacent to the UOD cutting defects. Moreover, abrupt temperature spikes of UOD use were noticed during the UOD cutting, and we have demonstrated neurothermal sequelae​ of UOD osteotomy that have not been reported elsewhere. Specifically, the mice cut by UOD showed mildly altered parietal lobe functions, and histological analyses showed brain defects sustained for more than 8 weeks, revealing a previously uncharacterized risk profile.

    Thermal dynamics in ultrasonic osteotome device applications​

    Our study demonstrated transient localized temperature spikes (> 60 °C) during UOD osteotomy using thermal imaging despite irrigation (Supplementary Material 1). This observation aligns with prior findings reporting elevated temperature during UOD procedures23,24,25,26.

    For instance, the observed temperature spikes align with Suzuki et al.’s findings in porcine bone, where UODs exceeded HSB temperatures by 28 °C27. Regarding in vivo experiments, transient tip temperatures exceeding 85 °C were recorded when UODs were cutting the inner cortex of the lamina during laminectomy, and after laminectomy, the average temperature of the inner cortex of the lamina was increased up to 11.4°C28. Without irrigation, the temperature of the cutting surface can reach up to 150 °C29.

    Increased temperature, known as heat shock or thermal insults during the bone osteotomy may hence result in thermal necrosis30causing an immediate necrotic response in bone cells or can induce longer apoptotic responses, with thresholds of 47 °C for 60 s or 50 °C for 30 s31,32,33. Variations in the temperature thresholds may be partly attributable to bone quality, as cancellous bone suffered greater damage from thermal treatment than cortical bone34.

    Cellular responses are triggered depending on the extent and duration of exposure to heat shock, leading to cell death by either necrosis or apoptosis, as shown in Figure S4. Thermal osteonecrosis consists of bone cell death and subversion of endosteal architecture32. Consequently, the bone will be resorbed and replaced with fibrous connective tissue33.

    Contemporary irrigation systems have markedly reduced the cutting temperature by using sharper cutting tips, constant irrigation, and controlled drilling speeds, among others35. Nevertheless, our study demonstrates that novel cooling methods still need further colling the cutting temperature to avoid osteonecrosis.

    Novel findings in bone structural alterations after piezosurgery

    On the one hand, our results are consistent with previous findings in several aspects36. First, the use of UOD can achieve a smooth cutting surface, and the bone defects can heal properly after the cutting, no worse than the HSB (Fig. 1B-C)36. Nevertheless, on the other hand, different from other studies, our H&E staining results show that the bones adjacent to the UOD cuts showed laminated-layered structural changes (Fig. 2), which is also true when cut with other UODs (Figure S2).

    Previous studies have presented mixed conclusions regarding the bone-cutting performance and bone-healing effects of UODs compared to conventional HSBs. For example, UODs were reported to have a superior bone healing profiles36,37,38. Specifically, UODs could produce a smooth cutting surface devoid of micro-fractures36 compared to HSB, facilitate bone healing compared to trephine burs37and favor the preservation of bone regions adjacent to osteotomies, although UODs may trigger variations in gene expression38.

    Nevertheless, other studies have stressed that replacing HSBs with UODs could not improve bone healing8,9,39,40and that using UODs would lead to distinct bone healing patterns. For instance, UODs could still induce micro-cracks formation, and different cutting modes or bone structures may yield irregular cutting performance39. Moreover, Bergonse Pereira Pedriali et al. reported that UODs delayed initial bone ossification, though fewer postoperative inflammatory responses were elicited40. No significant differences between rotating drills/saws and piezosurgery were reported by Esteves et al.8 and Ma et al.9and increased bone remodeling activity was found in the piezoelectric surgery group9.

    Novel findings in CNS structural and functional alterations after receiving piezosurgery

    While prior research suggested UODs have limited nerve damage potential and eventual recovery in peripheral nerves, our findings reveal significant and lasting structural and functional alterations in the central nervous system (CNS) following calvarial bone cutting.

    Critically, we observed pathological structural changes in the brain tissues underlying the bone cut, including edema, structural defects, and hyalinization (Fig. 2), indicative of thermal coagulative necrosis and cell death41. The histomorphometric findings align with hyperthermia-induced brain tissue damages, evidenced by apoptotic cells, fragmented nuclei, and hyalinized zones likely to be aggregated proteins from heat-denatured cytoskeletal components and hydrophobic interactions between damaged proteins42,43.

    These irreversible alterations correlate with functional deficits, demonstrating that the soft tissue selectivity of UODs is limited, and the damage to soft tissues may still occur during the cutting; this denotes a novel in vivo observation contrasting with ex vivo or peripheral nerve studies.

    The parietal cortex of rodents integrates multisensory information and coordinates spatial navigation, which can be investigated by tests assessing the Somatosensory Processing (viz., Adhesive Removal Test, Von Frey Filaments) and Spatial Cognition and Motor Integration (viz., Whisker-Nuisance Test, Puzzle Box Test)44,45,46,47,48. Nevertheless, the cylinder test was employed in this study as it can assess the distinction of the bilateral somatosensory processing and spatial cognition of parietal lobes20,21which are manifested as the contralateral motor functions.

    For CNS, past animal safety studies (Supplementary Table 1) using the spinal cord of cats49,50 and dogs51 using extreme exposure parameters (viz., prolonged direct contact, high energy levels not clinically used) have shown that there is an energy- and duration-dependent damage to the soft tissues with the use of UODs5. Although these studies stressed that the required injury parameters exceed clinical practice and suggested peripheral nerve injury was often transient with anticipated recovery5,51our observation of ​hyalinization and associated brain necrosis​ provides direct histopathological evidence that clinically encountered thermal energy transfer (as seen in device tip spikes > 60–70 °C) can inflict irreversible damage to adjacent vulnerable CNS tissues, underscoring a critical safety concern.

    For peripheral nervous tissues, prior investigations6 have found that direct exposure of a peripheral nerve to Piezosurgery, even in the worst-case scenarios, did not dissect the nerve transection but did induce some structural and functional damage in rat models, where the perineurium was damaged, and the functional test of the rats interfered6,7.

    Interestingly, after a thorough comparison with findings by Schaeren et al., we noticed that the UODs exerted similar structural alterations to the nerves, characterized by a multilayered wave-like morphology in their study6which is consistent with the multilayered wave-like morphology observed in the H&E brain tissues in this study.

    Clinical interpretations and future directions

    Bone healing after UOD osteotomy is influenced by device features and patient-specific factors, such as bone type (trabecular vs. cortical) and density (whether osteoporotic), as illustrated in Fig. 42,10,11,12,14. Suboptimal thermal management during osteotomy can impede healing, and future research should explore strategies to reduce heat production, optimize cutting parameters, and enhance bone healing, particularly in patients with osteoporosis or systemic comorbidities.

    Fig. 4

    The factors influencing bone healing when using ultrasonic osteotomy devices.

    Removal of bony elements in regions with complex anatomical structures is common in spine and cranial surgery; for instance, laminectomy and decompression of multilevel compressive myelopathy are technically challenging using traditional instruments in a highly narrow epidural space.

    Although systematic reviews have affirmed that laminectomy done with UODs was found to be safe, rapid, and effective with low blood loss52and spinal surgeries with a UOD were reported to show a reduction in osseous bleeding53durotomy and soft tissue damage still occur from time to time16.

    As shown in ex vivo cutting experiments, UOD generates significant localized heat at the cutting site, and our study has demonstrated that UOD cutting could cause underlying brain tissue damage in the mouse model. The heat generated from UOD cutting may be transferred to the brain tissues, causing thermal osteonecrosis, which may be attributable to the limited insulation that the thin mouse calvarial bone offered. Therefore, this finding may provide important clinical messages that extreme caution should be exercised when applying the UODs to remove bone where distance is limited and delicate tissues are in proximity, such as pediatric patients, skull base procedures, or surgeries near neurovascular structures, especially when these structures are known to be compromised or damaged.

    Strength and limitation

    This study is the first to directly compare the bone healing effects and brain tissue damage of UODs with HSB regarding brain tissue damage and behavioral tests using split calvarial bone defect models. However, limitations exist.

    First, the assessment of bone healing and soft tissue damage was limited to macroscopic and microscopic phenotypic levels without delving into molecular changes. Moreover, the density calibration was not conducted upon micro-CT scanning. Hence, density-based quantification was not possible, and future studies are needed to further validate the density-related damage and findings. Second, the use of mice, whose bone density and structure differ significantly from humans, limits the generalizability of our findings. However, the murine calvarial defect model remains valuable for simulating delicate bone-cutting procedures adjacent to central nervous tissue, such as in spine surgeries where durotomy may occur.

    Volumetric bone regeneration parameters​ such as bone volume fraction (BV/TV) or trabecular morphology were not investigated in this study, and the lack of microarchitectural analysis may impede the comprehensive characterization of mineralization patterns and bone quality maturation following thermal exposure. Future studies incorporating micro-CT analysis could provide critical insights into whether transient thermal spikes during UOD osteotomy would induce lasting alterations in cortical porosity or trabecular connectivity.

    Third, this study only conducted H&E staining, which may not distinctly distinguish the newly generated bone structure as other histomorphometric approaches54,55,56and only the coronal planes of the calvarial bone sections were conducted; hence, the measurements may be biased. Additionally, morphometric measurements were potentially biased because only coronal sections were analyzed, and the irregular shapes of the brain defects, combined with tissue distortion during compression and mounting, complicated accurate quantification. To minimize these biases, defect areas were determined by averaging three measurements. The operation duration was measured via an operation video clip from cutting to the end of the osteotomy, excluding skin excision and suture time. As the experiment subjects and osteotomy size are small, the operation duration measurements may not reflect the true surgical situation.

    Moreover, although device parameters were standardized at single output settings in this study throughout the experiments, with Sonicmed at 60% maximal cutting power and Misonix and Sonopet using clinically recommended presets, this approach does not account for performance variability across different power levels or irrigation regimens. Still, different setting parameters of each device were not tested, which may lead to difficulty in comparison and potential biases. Hence interpretation should be cautious and future studies are urged.

    Additionally, the sole reliance on thermal cameras to measure and record procedural temperature changes may not fully capture the heat transduction dynamics between the cutting tip and the target tissues during UOD procedures. Consequently, the potential effects of abrupt temperature changes during UOD cutting on bone healing and soft tissues warrant further investigation. These methodological constraints necessitate cautious interpretation of our results and validation studies in models more closely approximating human skeletal properties.

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  • Unusual carbon dioxide-rich disk detected around young star challenges planet formation models

    Unusual carbon dioxide-rich disk detected around young star challenges planet formation models

    image: 

    An image of the star-forming region NGC 6357 with the young star XUE 10. Observations with JWST/MIRI reveal a planet-forming disk whose spectrum shows clear detections of four distinct forms of carbon dioxide (CO2), but only little water, providing new insights into the chemical environment where planets are taking shape. Photo credit: Stockholm University (SU) and María Claudia Ramírez-Tannus, Max Planck Institute for Astronomy (MPIA).


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    Credit: Stockholm University (SU) and María Claudia Ramírez-Tannus, Max Planck Institute for Astronomy (MPIA).

    A study led by Jenny Frediani at Stockholm University has revealed a planet-forming disk with a strikingly unusual chemical composition: an unexpectedly high abundance of carbon dioxide (CO₂) in regions where Earth-like planets may one day form. The discovery, made using the James Webb Space Telescope (JWST), challenges long-standing assumptions about the chemistry of planetary birthplaces. The study is published in Astronomy & Astrophysics.

    “Unlike most nearby planet-forming disks, where water vapor dominates the inner regions, this disk is surprisingly rich in carbon dioxide,” says Jenny Frediani, PhD student at the Department of Astronomy, Stockholm University.

    “In fact, water is so scarce in this system that it’s barely detectable — a dramatic contrast to what we typically observe.”

    A newly formed star is initially deeply embedded in the gas cloud from which it was formed and creates a disk around itself where planets in turn can be formed. In conventional models of planet formation, pebbles rich in water ice drift from the cold outer disk toward the warmer inner regions, where the rising temperatures cause the ices to sublimate. This process usually results in strong water vapor signatures in the disk’s inner zones. However, in this case, the JWST/MIRI spectrum shows a puzzlingly strong carbon dioxide signature instead.

    “This challenges current models of disk chemistry and evolution since the high carbon dioxide levels relative to water cannot be easily explained by standard disk evolution processes,” Jenny Frediani explains.

    Arjan Bik, researcher at the Department of Astronomy, Stockholm University, adds, “Such a high abundance of carbon dioxide in the planet-forming zone is unexpected. It points to the possibility that intense ultraviolet radiation — either from the host star or neighbouring massive stars — is reshaping the chemistry of the disk.”

    The researchers also detected rare isotopic variants of carbon dioxide, enriched in either carbon-13 or the oxygen isotopes ¹⁷O and ¹⁸O, clearly visible in the JWST data. These isotopologues could offer vital clues to long-standing questions about the unusual isotopic fingerprints found in meteorites and comets — relics of our own Solar System’s formation.

    This CO₂-rich disk was found in the massive star-forming region NGC 6357, located approximately 1.7 kiloparsecs (about 53 quadrillion kilometers) away. The discovery was made by the eXtreme Ultraviolet Environments (XUE) collaboration, which focuses on how intense radiation fields impact disk chemistry.

    Maria-Claudia Ramirez-Tannus from the Max Planck Institute for Astronomy in Heidelberg and lead of the XUE collaboration says that it is an exciting discovery: “It reveals how extreme radiation environments — common in massive star-forming regions — can alter the building blocks of planets. Since most stars and likely most planets form in such regions, understanding these effects is essential for grasping the diversity of planetary atmospheres and their habitability potential.”

    Thanks to JWST’s MIRI instrument, astronomers can now observe distant, dust-enshrouded disks with unprecedented detail at infrared wavelengths — providing critical insights into the physical and chemical conditions that govern planet formation. By comparing these intense environments with quieter, more isolated regions, researchers are uncovering the environmental diversity that shapes emerging planetary systems. Astronomers at Stockholm University and Chalmers have helped develop the MIRI instrument which is a camera and a spectrograph that observes mid- to long-wavelength infrared radiation from 5 microns to 28 microns. It also has coronagraphs, specifically designed to observe exoplanets.

    The study “XUE: The CO_2-rich terrestrial planet-forming region of an externally irradiated Herbig disk” is published in Astronomy & Astrophysics.

    Journal

    Astronomy and Astrophysics

    Method of Research

    Observational study

    Subject of Research

    Not applicable

    Article Title

    XUE: The CO_2-rich terrestrial planet-forming region of an externally irradiated Herbig disk

    Article Publication Date

    29-Aug-2025

    Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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  • Galactic cannonballs: The mystery of hypervelocity white dwarfs may just have been solved

    Galactic cannonballs: The mystery of hypervelocity white dwarfs may just have been solved

    White dwarfs — the superdense, slowly cooling embers left behind when stars like our sun die — are usually quiet cosmic relics. A rare few, however, are anything but.

    In recent years, astronomers analyzing data from the European Space Agency’s Gaia spacecraft identified a handful of white dwarfs hurtling through the Milky Way at breakneck speeds of up to 1,240 miles per second (2,000 kilometers per second). That’s fast enough to zip from New York to Los Angeles in under two seconds — and to escape the galaxy entirely.

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  • How human hips evolved for walking on two legs

    How human hips evolved for walking on two legs

    A new study traces how our hips changed so our ancestors could walk on two legs. It identifies two precise changes during early development that reshaped the pelvis and set the stage for stable, efficient bipedal movement.

    The work follows what happens inside a forming hip, from early cartilage to bone. It clarifies when a key growth zone turns and when bone hardening is delayed, producing a short, wide, bowl-like pelvis suited for upright walking.

    Rotation of hip growth plate


    The research was led by Professor Terence D. Capellini, Chair of Human Evolutionary Biology at Harvard University.

    The first discovery centers on the growth plate, a thin zone where cartilage cells multiply and stack as a bone lengthens. In humans, the iliac growth plate starts out like other primates, then by day 53 of development it swings 90 degrees, so growth runs across the pelvis instead of head to tail.

    That single rotation turns the ilium from tall and narrow into short and wide. “What we’ve done here is demonstrate that in human evolution there was a complete mechanistic shift,” said Capellini.

    Delayed bone hardening

    The second change is all about timing. In a process called ossification, most bones start hardening from a center point in the shaft, then spread inward and outward.

    Human ilia break that pattern. Bone begins near the back, next to the sacrum, and spreads radially along the outer rim while the inside stays cartilaginous for roughly 16 weeks. This allows the pelvis to keep its shape as it enlarges.

    That delay keeps the “basin” geometry intact while muscles and ligaments find their anchors. “But the histology really revealed that it actually flipped 90 degrees,” said Capellini.

    Pelvis rotation and timing

    Behind those shifts are cells called chondrocytes that build cartilage and a ring of tissue called the perichondrium that helps initiate bone. The team mapped more than 300 active genes and highlighted three with outsized roles in these steps.

    Mutations in the SOX9 gene can cause campomelic dysplasia, which includes unusually narrow hip bones with reduced lateral flare. That clinical pattern matches what you would expect if iliac growth plate widening fails.

    Activating variants in the PTH1R gene cause Jansen metaphyseal chondrodysplasia, a disorder tied to abnormal growth plate signaling. Changes in that same pathway appear to help reorient the human iliac growth plate.

    Homozygous PTH1R (a genetic state where an individual inherits two non-functional copies of the PTH1R gene) mutations are linked to Eiken syndrome with delayed bone ossification. That mirrors the second developmental shift documented in the iliac growth plate’s development.

    Human hip changes began early

    The research team scanned and sectioned 128 embryonic and fetal samples, covering humans and nearly two dozen primates. The human pattern was different, and it was different early.

    According to the researchers, the growth plate reorientation began after our branch split from African apes. Later, as selection balanced walking efficiency with childbirth, the ossification delay likely emerged to preserve shape while the pelvis grew.

    “All fossil hominids from that point on were growing the pelvis differently from any other primate that came before,” said Capellini.

    Pelvis shaped walking and birth

    A short, wide ilium changes how key muscles work. The flaring blades reposition gluteus medius and gluteus minimus muscles so they stabilize the pelvis when one leg is on the ground during a step.

    Comparative work shows that flaring ilia reorient hip muscles and influence birth canal shape, as outlined in a review. That broader context helps explain why the pelvis must serve walking, load transfer, and childbirth together.

    The study also notes early attachments for the rectus femoris and the iliofemoral ligament near the front of the ilium. Those connections fit the demands of upright gait and help resist pelvic drop during single-leg support.

    Tracking changes in hips

    The investigators combined micro CT with histology to see shape changes over time. They then layered single-cell multiomics and spatial transcriptomics to match gene activity with exact locations in the tissue.

    That blend linked a rotated growth plate to SOX9, PTH1R, and related signals. It also tied the unusual rim-first, inside-late ossification to the RUNX2 gene and factors that govern when and where bone cells appear.

    The combined picture shows a coordinated pathway that first widens the pelvic blades, then slows internal mineralization to hold geometry while size increases. That two-step sequence explains the basin-like hips required for stable bipedalism.

    Many questions remain

    Open questions remain about how mechanical forces from early muscle contractions might reinforce the new growth directions. It is also unclear how much variation these developmental programs show across modern human populations.

    Future work can probe how regulatory DNA near these genes changed through time. That could reveal whether selection acted in bursts or nudged many switches at once.

    The study is published in the journal Nature.

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  • Spiders use fireflies’ glow in the dark to catch more prey in webs

    Spiders use fireflies’ glow in the dark to catch more prey in webs

    A nocturnal spider in the East Asian subtropical forests has created an unusual hunting strategy. 

    This cunning predator is a nocturnal sheet web spider, Psechrus clavis, which captures fireflies as prey.

    Rather than immediately consuming captured fireflies, the spider leaves them in its web to continue emitting their bioluminescent light. 

    This light, which the fireflies use to attract mates, acts as a lure for other prey.

    Researchers in Taiwan documented this rare case of a predator exploiting its prey’s mating signal to its own advantage.

    “Our findings highlight a previously undocumented interaction where firefly signals, intended for sexual communication, are also beneficial to spiders,” said Dr I-Min Tso, the study’s lead author. 

    “This study sheds new light on the ways that nocturnal sit-and-wait predators can rise to the challenges of attracting prey and provides a unique perspective on the complexity of predator-prey interactions,” the author added.

    LED light experiment

    The nocturnal sheet web spider is a sit-and-wait predator. Its primary food source is the winter firefly (Diaphanes lampyroides), which attracts mates with a continuous, non-flashing light.

    The team experimented using LED lights to mimic the fireflies’ glow in real spider webs. Other webs were left untouched to act as a control group.

    Surprisingly, the webs adorned with these artificial lures attracted three times the prey. This number jumped to ten times more when they only counted the fireflies caught.

    The study confirmed that spiders that use captured fireflies as bait are much more successful at hunting.

    Most of the fireflies caught were male, likely drawn in by the glow they mistook for a mate.

    Researchers believe this strategy allows the spiders to “outsource” prey attraction, avoiding the need to develop their own bioluminescence, similar to other night predators like anglerfish.

    Differentiating prey

    The experiment also revealed that the spiders use different strategies for handling various types of prey. 

    For instance, when a moth was caught in the web, the spiders would immediately consume it. However, if a firefly were captured, the spiders would not eat it immediately.

    This suggests the spiders can distinguish between different species and adjust their behavior accordingly.

    “Handling prey in different ways suggests that the spider can use some kind of cue to distinguish between the prey species they capture and determine an appropriate response,” explained Tso. 

    “We speculate that it is probably the bioluminescent signals of the fireflies that are used to identify fireflies, enabling spiders to adjust their prey handling behavior accordingly,” Tso added in the press release.

    The researchers conducted a field experiment in a conifer plantation forest at the Xitou Nature Educational Area of National Taiwan University. 

    They noted a limitation in their methodology: they used LEDs to imitate the light of fireflies.

    While the wavelength and intensity of the LEDs closely matched those of the fireflies, the researchers acknowledge that using real fireflies would have been ideal for the experiment. However, they admitted that doing so would have been practically impossible.

    The findings were published in the British Ecological Society’s Journal of Animal Ecology.

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  • DNA From a Mysterious Extinct Hominin May Have Helped Ancient Americans Survive

    DNA From a Mysterious Extinct Hominin May Have Helped Ancient Americans Survive

    New research suggests that as ancient humans migrated into the Americas, they carried a surprising evolutionary advantage hidden within their DNA. This genetic code, passed down from an extinct species of hominin, may have been crucial for adapting to the unique environmental challenges of a new world. Credit: Stock

    A newly discovered Denisovan gene, hidden within human DNA, may have helped the first Americans adapt to their new world.

    Thousands of years ago, early humans braved a dangerous migration, traveling across vast stretches of ice over the Bering Strait to reach the unfamiliar lands of the Americas.

    According to new research from the University of Colorado Boulder, these travelers may have brought along something unexpected: a piece of DNA inherited from a now-extinct hominin species. This genetic legacy could have played a key role in helping them survive and adapt to the challenges of their new environment.

    The researchers recently published their findings the journal Science.

    “In terms of evolution, this is an incredible leap,” said Fernando Villanea, one of two lead authors of the study and an assistant professor in the Department of Anthropology at CU Boulder. “It shows an amount of adaptation and resilience within a population that is simply amazing.”

    The work focuses on Denisovans, a mysterious branch of the human family tree. These ancient relatives once lived across a wide region stretching from modern-day Russia down to Oceania and westward to the Tibetan Plateau, before disappearing tens of thousands of years ago. Much about them is still uncertain: the first Denisovan was only identified 15 years ago through DNA extracted from a bone fragment discovered in a Siberian cave. Physical traits remain largely speculative, though like Neanderthals, they may have had heavy brows and lacked chins.

    Denisova Cave
    Scientists discovered remains belonging to the first known Denisovan, who likely died more than 50,000 years ago, in a cave in Russia called Denisova, hence the name. Credit: Wikimedia Commons

    “We know more about their genomes and how their body chemistry behaves than we do about what they looked like,” Villanea said.

    A growing body of research has shown that Denisovans interbred with both Neanderthals and humans, profoundly shaping the biology of people living today.

    To explore those connections, Villanea and his colleagues including co-lead author David Peede from Brown University, examined the genomes of humans from across the globe. In particular, the team set its sights on a gene called MUC19, which plays an important role in the immune system.

    The group discovered that humans with Indigenous American ancestry are more likely than other populations to carry a variant of this gene that came from Denisovans. In other words, this ancient genetic heritage may have helped humans survive in the completely new ecosystems of North and South America.

    A little-known gene

    Villanea added that MUC19’s function in the human body is about as mysterious as Denisovans themselves. It’s one of 22 genes in mammals that produce mucins. These proteins make mucus, which, among other functions, can protect tissues from pathogens.

    “It seems like MUC19 has a lot of functional consequences for health, but we’re only starting to understand these genes,” he said.

    Previous research has shown that Denisovans carried their own variant of the MUC19 gene, with a unique series of mutations, which they passed onto some humans. That kind of admixture was common in the ancient world: Most humans alive today carry some Neanderthal DNA, whereas Denisovan DNA makes up as much as 5% of the genomes of people from Papua New Guinea.

    Map of a Land Bridge Connecting Modern Day Russia to Alaska
    Map of a land bridge connecting modern-day Russia to Alaska roughly 21,000 years ago. Credit: U.S. National Park Service

    In the current study, Villanea and colleagues wanted to learn more about how these genetic time capsules shape our evolution.

    The group pored through already published data on the genomes of modern humans from Mexico, Peru, Puerto Rico, and Colombia, where Indigenous American ancestry and DNA are common.

    They discovered that one in three modern people of Mexican ancestry carry a copy of the Denisovan variant of MUC19—and particularly in portions of their genome that come from Indigenous American heritage. That’s in contrast to people of Central European ancestry, only 1% of whom carry this variant.

    The researchers discovered something even more surprising: In humans, the Denisovan gene variant seems to be surrounded by DNA from Neanderthals.

    “This DNA is like an Oreo, with a Denisovan center and Neanderthal cookies,” Villanea said.

    A new world

    Here’s what Villanea and his colleagues suspect happened: Before humans crossed the Bering Strait, Denisovans interbred with Neanderthals, passing the Denisovan MUC19 to their offspring. Then, in a game of genetic telephone, Neanderthals bred with humans, sharing some Denisovan DNA. It’s the first time scientists have identified of DNA jumping from Denisovans to Neanderthals and then humans.

    Harbin Cranium
    In June 2025, researchers reported that the “Harbin cranium,” originally unearthed in the 1930s, likely belonged to a Denisovan. To date, it is the only known Denisovan skull. Credit: Fu et al., Cell, 2025

    Later, humans migrated to the Americas, where natural selection favored the spread of this borrowed MUC19.

    Why the Denisovan variant became so common in North and South America but not in other parts of the world isn’t yet clear. Villanea noted that the first people who lived in the Americas likely encountered conditions unlike anything else in human history, including new kinds of food and diseases. Denisovan DNA may have given them additional tools to contend with challenges like these.

    “All of a sudden, people had to find new ways to hunt, new ways to farm, and they developed really cool technology in response to those challenges,” he said. “But, over 20,000 years, their bodies were also adapting at a biological level.”

    To build that picture, the anthropologist is planning to study how different MUC19 gene variants affect the health of humans living today. For now, Villanea said the study is a testament to the power of human evolution.

    “What Indigenous American populations did was really incredible,” Villanea said. “They went from a common ancestor living around the Bering Strait to adapting biologically and culturally to this new continent that has every single type of biome in the world.”

    Reference: “The MUC19 gene: An evolutionary history of recurrent introgression and natural selection” by Fernando A. Villanea, David Peede, Eli J. Kaufman, Valeria Añorve-Garibay, Elizabeth T. Chevy, Viridiana Villa-Islas, Kelsey E. Witt, Roberta Zeloni, Davide Marnetto, Priya Moorjani, Flora Jay, Paul N. Valdmanis, María C. Ávila-Arcos and Emilia Huerta-Sánchez, 21 August 2025, Science.
    DOI: 10.1126/science.adl0882

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  • This smart sensor showed me the hidden reality of electrical fire hazards at home

    This smart sensor showed me the hidden reality of electrical fire hazards at home

    Maria Diaz/ZDNET

    Get more in-depth ZDNET tech coverage: Add us as a preferred Google source on Chrome and Chromium browsers.

    I’ve had the Ting smart sensor monitor my home’s electrical system and assess the risk of electrical fires for months, and I’ve been pleasantly surprised by how informative the process has been. 

    The Ting features an easy installation — no wiring or electricians involved. You only need to plug it in to get it started. Once you download the Ting mobile app, you can connect the sensor to Wi-Fi. You have to wait a few weeks for the Ting to familiarize itself with your home’s electrical system before it gives you consistent status updates. 

    Also: 8 smart home gadgets that instantly upgraded my house (and why they work)

    After learning your home, the Ting sensor monitors the electrical current 24/7, looking for issues in wiring, outlets, and even appliances. Basically, the Ting monitors all the electrical in your house that could spark an electrical fire, including incoming power. It also watches your home’s voltage, power outages, and upcoming storms that may cause you to lose power.

    Ting detects electrical issues that you would otherwise not know about, which could potentially start a fire. These could include loose or damaged connections, like frayed cords, worn insulation, overloads, and faulty equipment.

    Also: Unplugging these 7 common household devices greatly reduced my electricity bill

    Aside from detecting significant issues in electricity, Ting can detect arcing, tiny electrical sparks that can happen due to age, poor installation, or bad construction. These scintillations are early warning signs that turn into bigger issues down the road, like tripped breakers or electrical fires. 

    Get more in-depth ZDNET tech coverage: Add us as a preferred Google source on Chrome and Chromium browsers.

    Why I recommend this product

    The Ting smart sensor is one of the easiest ways to gain extra insight into your home’s electrical status. It alerts you when changes occur, including when the risk of an electrical fire increases. 

    Even if a Ting sensor does not replace a smoke alarm, an alarm only alerts you after a fire has started and smoke has been detected. In contrast, a Ting alerts you of the possibility of a fire before it ignites. However, not all fires are caused by electrical issues, so having reliable smoke alarms is still imperative, Ting sensor or not. 

    Beyond monitoring electrical safety, I love that Ting keeps me notified of power outages and even provides insight into nearby outages and potential risks for one happening in my home. When I’m away, Ting also tells me of severe weather alerts and a detailed log of when the power went out and when service was restored.

    Looking for the next best product? Get expert reviews and editor favorites with ZDNET Recommends.


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  • Clonogenic hepatocytes identified as engines of liver development

    Clonogenic hepatocytes identified as engines of liver development

    In a new study published in the Journal of Hepatology, researchers from the San Raffaele Telethon Institute for Gene Therapy (SR-Tiget) show that only 15–20% of hepatocytes in newborn mice – dubbed clonogenic hepatocytes – are responsible for generating over 90% of the adult liver mass.

    These findings have major implications for pediatric gene therapy. Understanding the dynamics of this subset of hepatocytes early in life can help scientists to achieve more effective and durable correction of inherited liver diseases through in vivo gene engineering strategies such as lentiviral gene transfer and genome editing.

    Latest-generation technologies reveal cellular blueprints

    The team combined cutting-edge single-cell and spatial transcriptomics, clonal tracing, and mathematical modeling to analyze how hepatocytes proliferate and mature after birth. This approach allowed them to identify not only the clonogenic cells but also the molecular signals and tissue niches that regulate their activity.

    Using spatial transcriptomics, we captured the precise localization and transcriptional identity of hepatocytes during postnatal liver growth. It gave us an unprecedented view into how different hepatocyte subsets proliferate and mature.”


    Dr. Michela Milani, co-first author of the study

    Timing and cell identity shape gene therapy success

    The researchers found that gene editing by homology-directed repair (HDR) is significantly enriched within the clonogenic hepatocytes, thus resulting in an expansion of the proportion of the gene-edited liver area at the end of the organ growth. On the other hand, lentiviral vectors distribute more evenly across hepatocyte populations, but their efficiency is affected by the maturation state and lobular position of the cells – particularly the emergence of peri-central (PC) identity after weaning, which is associated with reduced vector permissiveness due to elevated proteasome activity.

    “Knowing that the liver becomes less permissive to gene transfer in certain zones as it matures helps us refine not just what cells to target, but also when to treat,” says Dr. Francesco Starinieri, co-first author.

    Pre-treatment with a proteasome inhibitor restored lentiviral transduction in adult hepatocytes, suggesting that this barrier can be pharmacologically modulated to improve gene delivery in mature livers.

    A shared niche for growth and proliferation

    Another key finding is the discovery of a specialized instructive tissue niche in neonatal livers, where clonogenic hepatocytes are found in close proximity to hematopoietic progenitor cells. This spatial co-localization suggests a shared pool of growth signals and might open up new possibilities for regenerative medicine.

    Toward durable pediatric gene therapies

    “This study extends our understanding of how the liver grows and matures and how we can intervene early in life to durably correct genetic diseases,” says Dr. Alessio Cantore, senior and corresponding author. “By identifying the specific hepatocytes that fuel liver growth – and how they respond to gene delivery – we can now rationally design more effective and lasting therapies for children.”

    Dr. Cantore recently received a prestigious Consolidator Grant from the European Research Council (ERC) to further investigate liver tissue dynamics mechanisms and translate them into therapeutic applications.

    The research was conducted in collaboration with Dr. Andrés Muro of the International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, and involved multidisciplinary contributions from molecular biologists, physicists, and bioinformaticians at SR-Tiget and the San Raffaele Scientific Institute.

    This research was mainly supported by Fondazione Telethon, the Italian Ministry of Health, and the EU Horizon 2020 Program.

    Source:

    Journal reference:

    Milani, M., et al. (2025). Spatiotemporal liver dynamics shape hepatocellular heterogeneity and impact in vivo gene engineering. Journal of Hepatology. doi.org/10.1016/j.jhep.2025.06.018

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  • Webb discovers what’s behind Butterfly Nebula’s signature glow

    Webb discovers what’s behind Butterfly Nebula’s signature glow

    Scientists were able to pinpoint the location of the Butterfly Nebula’s central star. This had not been done before.

    The James Webb Space Telescope has unearthed new details at the core of the Butterfly Nebula – one of the best studied planetary nebulas in the Milky Way galaxy. These new observations paint a “never-before-seen” portrait of this beautiful stellar object, say scientists.

    The Butterfly Nebula is located roughly 3,400 light-years away in the Scorpius constellation. Although it is called a “planetary” nebula, the term has nothing to do with planets. These names were first coined hundreds of years ago when astronomers reported that these nebulas looked to be round – like planets. Not to mention, the term is particularly unfit for the Butterfly Nebula, which most definitely does not look round.

    Nevertheless, planetary nebulas are formed when stars with masses between 0.8 to 8 times the mass of the sun shed most of their mass at the end of their lives. They are considerably short-lived when compared to much of what exists in the universe, lasting only around 20,000 years.

    The Butterfly Nebula is a bipolar nebula, meaning it has two lobes spreading out in opposite directions – forming the image of the wings of a butterfly. The body of the nebula is shaped like a doughnut, or a torus, which hides the nebula’s central star.

    The Butterfly Nebula as seen in wavelengths of light visible to us. Image: ESA/Webb, NASA & CSA, K Noll, J Kastner, M Zamani (ESA/Webb)

    The Webb’s new image zooms in at this centre using the Mid-InfraRed Instrument (MIRI). The camera is able to take images at many different wavelengths simultaneously, revealing how an object’s appearance changes at the various wavelengths.

    Moreover, the research team supplemented the Webb observations with data from the Atacama Large Millimeter/submillimeter Array (ALMA).

    The team was able to identify almost 200 spectral lines, each of which holds information about the atoms and molecules in the nebula. They were also able to pinpoint the location of the Butterfly Nebula’s central star, which had not been done before.

    According to the scientists, the central star has a previously undetected dust cloud around it, making the cloud shine brightly at the mid-infrared wavelengths which the MIRI is capable of picking up. With a temperature of 220,000 Kelvin, this is one of the hottest known central stars in a planetary nebula in our galaxy. The hot stellar engine is responsible for the nebula’s memorable glow.

    Another interesting find from Webb is light emitted by carbon-based molecules known as polycyclic aromatic hydrocarbons (PAHs).

    On Earth, PAHs are often found from campfire smoke, car exhausts or burnt toast. According to the scientists, this may be the first-ever evidence of PAHs forming in an oxygen-rich planetary nebula.

    Earlier this month, a study led by the University of St Andrews using the James Webb found some evidence to suggest that free-floating planets could make their own miniature planetary systems without needing a star to orbit around.

    Don’t miss out on the knowledge you need to succeed. Sign up for the Daily Brief, Silicon Republic’s digest of need-to-know sci-tech news.

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  • Aromatic compound in deep space is biggest yet. Plays key role in planet, star formation and possibly life

    Aromatic compound in deep space is biggest yet. Plays key role in planet, star formation and possibly life

    Deep in the cold, dark recesses of a lightyears-wide nebula known as the Taurus molecular cloud (TMC-1), astronomers have discovered cyanocoronene, the largest polycyclic aromatic hydrocarbon (PAH) ever detected in space.

    PAHs have a bad reputation on Earth, as they arise from the incomplete combustion of organic matter, such as in tobacco smoke or exhaust fumes, with harmful implications to health.

    In the broader Universe, however, they are thought to lock away carbon and play a key role in the chemistry that leads to the formation of stars and planets.

    The study recreated cyanocoronene in the lab to determine its unique chemical signature.

    With this in hand, scientists tracked observational data from TMC-1, finding clear signs of the large PAH.

    Containing 24 carbon atoms, it is the largest individual PAH to have been detected in interstellar space.

    Why it matters

    The cyanocoronene was in similar amounts to smaller PAHs found before, hinting that such molecules may be more common in space than previously thought.

    They could act as stable reservoirs of carbon, seeding new planetary systems with the ingredients for life.

    Researchers now aim to find even larger PAHs and to understand how they survive the extremes of space.

    “Each new detection brings us closer to understanding the origins of complex organic chemistry in the Universe – and perhaps, the origins of the building blocks of life themselves,” says lead researcher Gabi Wenzel.

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