It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Monday, April 20, 2026
Deep earthquakes triggered by the olivine-poirierite transition
Seismicity decreases with depth because elevated confining pressure prevents frictional sliding of faults. However, seismicity tends to increase with depth in the mantle transition zone (depths of 410−600km). It has been believed that pressure-induced phase transitions of olivine in the ‘cold’ subducted slabs is the cause of high seismicity in the mantle transition zone.
The mechanism of deep earthquake has been studied for four decades. It has been considered that the pressure-induced phase transition of olivine induces shear localization to spinel-filled lens, followed by a deep earthquake. This ‘transformational faulting’ model has been experimentally tested by researchers using germanite olivine or mantle olivine. However, the olivine-ringwoodite transition is too sluggish to induce deep earthquakes in the cold core of the deep subducted slabs (600ºC), such as the Mariana slab, if we assume the diffusion-controlled nucleation of ringwoodite on olivine grain boundaries. A plausible explanation for the olivine-ringwoodite transition in the cold deep slabs may be the diffusionless pseudo-martensitic transition (i.e., shear transition) of olivine to ringwoodite. Recent studies showed that an intermediate structure of poirierite needs to be formed when the diffusionless shear transition of olivine-ringwoodite proceeds.
We conducted deformation experiments on metastable olivine under the pressure-temperature conditions of deep subducted slabs. We carefully observed the faulted olivine samples, which were obtained in our experiments, and we found poirierite grains in the fault gouge. The observed crystallographic orientations of poirierite and olivine grains are consistent with a theoretical model. The poirierite grains transform to ringwoodite as a result of shear deformation. Release of quite high latent heat via the poirierite-ringwoodite transition can induce a significant weakening of the fault gouge, without the aid of grain-size-sensitive creep, resulting in the occurrence of faulting. The diffusionless phase transition of olivine to ringwoodite via poirierite is effective not only at high temperatures but at low temperatures. Our findings provide a natural explanation for the cause of high seismicity in the strongly deformed areas of ‘cold’ deep subducted slabs.
Left and center: kinking (i.e., shear deformation) of an olivine crystal at pressures greater than 15 GPa results in the formation of a poirierite crystal. Right: Further shear transition of poirierite to ringwoodite associates a significant latent heat release, resulting in faulting.
Seismicity is high in the strongly deformed areas in the deep subducted slabs. Our model (i.e,. shear transition of olivine to ringwoodite via poirierite) provides a natural explanation for the cause of high seismicity in the strongly deformed areas of deep subducted slabs.
Recent progress in advanced energy manufacturing has opened a new path for lithium battery design. A joint research team led by Associate Professor Eric Jianfeng Cheng of Tohoku University has published a major review in Materials Science and Engineering: R: Reports on March 30, 2026, that highlights the potential, the pitfalls, and different perspectives of 3D printing's role in manufacturing lithium batteries. The article provides a systematic roadmap for how 3D printing may redefine next-generation lithium batteries.
The review shows that 3D printing can move battery manufacturing beyond the geometric limits of conventional coating-based production. Instead of relying on flat, stacked shapes, 3D printing enables precise control over three-dimensional structures. This topology-driven design can shorten ion-transport pathways, improve electron conduction, reduce local stress concentration during cycling, and enhance mechanical robustness. In this sense, 3D printing is not simply a new processing method, but a way to redesign how electrochemical performance is built into battery structure itself.
The paper places particular emphasis on all-solid-state lithium batteries, where both energy density and interface quality are critical. For these systems, the challenge is not merely to print battery components, but to fabricate thin, structurally precise solid-electrolyte architectures while maintaining low interfacial resistance and reliable ionic transport. The review critically analyzes the key scientific bottlenecks involved, especially the trade-off between high ceramic filler content, ink rheology, sub-100-micrometer structural fidelity, and interfacial integrity in composite solid electrolytes.
"We believe the next stage of progress will depend on integrating artificial intelligence (AI) with 3D printing," says Siraprapha Deebansok (Tohoku University). "The guidance of data-driven AI can help us move away from trial-and-error, and towards intelligent manufacturability."
This research provides one of the most comprehensive roadmaps to date for applying 3D printing technologies to lithium battery manufacturing. The research team thoroughly examines how the precise control of 3D printing could improve a battery's energy density, safety, and stability. This framework may accelerate the design of advanced batteries for electric vehicles, flexible electronics, and grid-scale energy storage.
About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).
See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI Main WPI program site: www.jsps.go.jp/english/e-toplevel
Advanced Institute for Materials Research (AIMR) Tohoku University Establishing a World-Leading Research Center for Materials Science
AIMR aims to contribute to society through its actions as a world-leading research center for materials science and push the boundaries of research frontiers. To this end, the institute gathers excellent researchers in the fields of physics, chemistry, materials science, engineering, and mathematics and provides a world-class research environment.
3D printing in lithium battery manufacturing: Opportunities, challenges, and perspectives
The bacterium responsible for scarlet fever was not introduced to the Americas by Europeans.
A research team led by Eurac Research has identified the Streptococcus pyogenes bacterium in a pre-Columbian Bolivian mummy and, for the first time, reconstructed the genome of this centuries-old pathogen.
Bolivian biochemist Guido Valverde in a storage room at the National Archaeological Museum (MUNARQ) in La Paz. On the shelves: the museum’s collection of skulls
Researchers identified the pathogen’s genetic material while examining a tooth from a naturally mummified skull housed at MUNARQ – the National Museum of Archaeology in La Paz. Using a method that reassembles previously unknown genomes from numerous short DNA fragments, they reconstructed a nearly complete, ancient genome of Streptococcus pyogenes. The reconstructed genome shows clear similarities to modern strains of the globally widespread bacterium, which can cause a variety of illnesses ranging from harmless throat infections to scarlet fever and life-threatening toxic shock syndrome. Despite the pathogen’s great medical significance: scarlet fever was historically one of the leading causes of death among children, little is known about its evolutionary history. This finding now shows that the bacterium was already circulating among indigenous populations in South America before European colonization: the young man from whom the tooth originated lived between 1283 and 1383 AD. The study was made possible by a cooperation agreement between Eurac Research and the Bolivian Ministry of Cultures and has been published in Nature Communications.
“We weren’t looking for this pathogen specifically,” emphasizes Frank Maixner, director of the Eurac Research Institute for Mummy Studies: “When conducting genetic analyses of mummies, we approach the work with an open mind, analyzing not only human genetic material but also the DNA of the numerous microorganisms present in human remains.”
Among the bacterial DNA traces the researchers found in the tooth, Streptococcus pyogenes was common. Because the pathogen remains medically significant today – with scarlet fever outbreaks on the rise worldwide – the team analyzed this genetic material in greater detail.
To reconstruct the several-hundred-year-old genome, the researchers used de-novo assembly, an established method of modern genome research that the Institute for Mummy Studies has further developed specifically for highly fragmented ancient DNA. It allows a genome to be reassembled from many DNA fragments without a reference genome as a template. “You can think of it like putting together a puzzle without knowing the picture on the box,” explains Microbiologist Mohamed Sarhan of Eurac Research, who shares first authorship of the paper with Bolivian biochemist Guido Valverde. “This method has a major advantage for reconstructing ancient genomes: we are not influenced by modern references – we work without preconceptions. This allows us to discover entirely new insights and also identify genetic variants that may no longer exist today, such as extinct bacterial strains.” For the field of research, this possibility signifies “something like the beginning of a new era,” adds Maixner.
Given its age, the bacterium’s DNA was relatively well-preserved, which the researchers attribute to the dry and cold conditions in the Bolivian highlands. This unique climate also facilitated the natural mummification of the skull – attributed to the Late Intermediate Period (1100 – 1450 AD). Using radiocarbon dating and, according to genetic analyses, it was found that the skull belongs to a young man of indigenous descent. It is likely, as is the case with most of the museum’s other mummies, that the skull was found in a chullpa – one of the typical burial towers of the Bolivian Altiplano.
“The DNA’s excellent preservation enabled us to reconstruct a nearly complete genome, yielding a wealth of information and demonstrating, for example, that the bacterium was already capable of causing disease: the ancient strain carried many – though not all – of the pathogenic genes found in modern Streptococcus pyogenes strains,” explains Valverde. This ancient pathogen was found to be particularly similar to modern strains that primarily cause throat infections.
During a targeted search of other publicly available datasets of ancient DNA, the researchers found Streptococcus pyogenes in 35 samples from people who lived in Europe about 4,000 years ago, as well as a closely related Streptococcus species in 200-year-old remains of gorillas from Africa, demonstrating that the pathogen was present already in ancient samples but had been overlooked for years.
The researchers’ genetic analyses also indicate that the evolutionary lineages of most modern Streptococcus pyogenes strains diverged around 5,000 years ago – during an era when humans were becoming increasingly sedentary and living in closer proximity. This may have facilitated the spread and diversification of the pathogen, which is primarily transmitted through droplet and contact transmission.
The study is part of a large interdisciplinary project that is conducting the first systematic bioarcheological analysis of the mummy collection at the Bolivian National Museum of Archaeology (MUNARQ). It is freely accessible at: https://www.nature.com/articles/s41467-026-71603-9
An ancient genome of Streptococcus pyogenes from a pre-Columbian Bolivian mummy.
Article Publication Date
13-Apr-2026
Chullpas on the Bolivian Altiplano. These burial towers are the remains of a civilization that preceded the Inca Empire.
Credit
Juan Gabriel Estellano
This tooth belonged to a young man who lived on the Bolivian Altiplano around 700 years ago. The research team detected the scarlet fever bacterium, Streptococcus pyogenes, in it.
Credit
Guido Valverde
Ancient charcoal sheds new light on how early humans fueled their lives
New study shows that early humans living about 800,000 years ago depended on fire in smart, practical ways. Instead of searching for the “best” wood, they took advantage of what nature provided, mainly driftwood collected along the lakeshore. This reliable fuel supply helped them keep fires going for cooking and daily life, and may even explain why they kept coming back to the same spot. In other words, they weren’t just choosing a place to live, they were choosing a place where fire was easy to maintain.
Nearly 800,000 years ago, early humans gathered along the shores of a lush lake in what is now northern Israel. Here, they returned again and again, hunting large animals, cooking fish over controlled fires, and organizing their daily lives around hearths. Now, a new study shows that even the wood fueling those fires, which is preserved as rare fragments of charcoal, can reveal how carefully these ancient communities understood and used their environment.
Published in Quaternary Science Reviews, the study offers a vivid reconstruction of life at the Acheulian site of Gesher Benot Ya'aqov (GBY). By examining an exceptionally rich and rare collection of ancient charcoal, an international team of researchers from Israel, Spain, and Germany, including Prof. Naama Goren-Inbar (Hebrew University), Prof. Nira Alperson-Afil and Dr. Yoel Melamed (Bar-Ilan University), Prof. Ethel Allué (Universitat Rovira i Virgili and Institut Català de Paleoecologia), and Prof. Brigitte Urban (Leuphana University), has uncovered new evidence of how early hominins gathered and used firewood, revealing behavior far more sophisticated than previously assumed.
Charcoal rarely survives at such early prehistoric sites, making this unusually large assemblage a unique window into the daily practices of early fire users. While many ancient sites preserve only fragmentary or ambiguous traces of burning, GBY provides a remarkably detailed record of repeated fire use over tens of thousands of years.
GBY preserves a layered history of human occupation along the shores of paleo–Lake Hula, with more than 20 archaeological horizons documenting generations of Acheulian hunter-gatherers returning to the same location. Excavations led by Prof. Naama Goren-Inbar of the Hebrew University of Jerusalem have revealed a dynamic landscape of activity: stone tools crafted from flint, limestone, and basalt; the remains of hunted animals; and a wide array of plant foods, including fruits, nuts, and seeds gathered from the lakeshore.
One particularly striking layer captures a dramatic moment in time. Alongside stone tools and plant remains, researchers uncovered the skull and bones of a straight-tusked elephant, evidence of large-scale hunting and butchery. The spatial arrangement of the remains suggests that the animal was processed on-site.
At the heart of this ancient camp life was fire. First identified at GBY by Prof. Nira Alperson-Afil of Bar-Ilan University, fire was habitual. It structured how space was organized, anchoring activities such as tool production, food preparation, and social interaction.
The new study focuses on a single occupation layer dated to approximately 780,000 years ago. Researchers analyzed 266 charcoal fragments, using microscopic techniques to identify the internal structure of the wood and determine its botanical origin. The results revealed a surprisingly diverse mix of plant species, including ash, willow, grapevine, oleander, olive, oak, pistachio, and even pomegranate, which is the earliest known evidence of this fruit tree in the Levant.
Unexpectedly, the charcoal assemblage showed greater plant diversity than other botanical remains from the site, such as seeds, fruits, or unburned wood. This suggests that firewood collection captured a broader cross-section of the surrounding environment than other forms of plant use.
Together, these species paint a vivid picture of the ancient landscape: a mosaic of wet lakeshore vegetation and open Mediterranean woodland. But more importantly, they reveal how early humans interacted with that landscape.
Rather than selectively gathering specific types of wood, GBY hominins appear to have relied primarily on driftwood naturally accumulating along the lakeshore. Fallen branches and logs, carried by water and deposited along the shore, would have created a readily available fuel supply. The composition of the charcoal closely mirrors the wood available in this environment, suggesting a practical and efficient strategy, using what the landscape provides.
This insight points to a broader conclusion: access to firewood may have been a decisive factor in where these early humans chose to live. The lakeshore offered not only fresh water, edible plants, animals, and raw materials for tools, but also a constant supply of fuel, essential for maintaining fire.
Even more striking is how fire was used. Spatial analysis shows that dense clusters of charcoal overlap with concentrations of fish remains, primarily the distinctive teeth of large carp. This co-occurrence adds compelling evidence that fish were being cooked at the site nearly 800,000 years ago, likely using carefully controlled fire.
These findings reinforce the idea that GBY hominins possessed advanced cognitive abilities. They were capable of controlling fire, organizing space around it, and integrating it into complex subsistence strategies. Yet interestingly, while hunting and tool-making required elaborate planning, firewood collection itself appears to have been a more routine activity, based largely on availability rather than careful selection of specific tree species.
Together, these behaviors paint a picture of a community that was both highly skilled and deeply attuned to its environment, returning repeatedly to a place that offered everything they needed to survive and thrive.
The GBY charcoal assemblage provides a unique dataset for examining the intersection of fire use, environmental context, and hominin behavior. These findings refine current models of early fire-related practices and emphasize the importance of local resource availability in shaping patterns of occupation and subsistence during the Middle Pleistocene.
Traverse section of a charcoal fragment of ash observed under an ESEM microscope
