Violent supershear earthquakes are more common than previously thought

A section of the San Andreas Fault between Bakersfield and Santa Barbara, California. UCLA’s Lingsen Meng said the reason relatively few supershear earthquakes were reported previously is that researchers tended not to count those that occur underwater.
Photo Credit: Carol M. Highsmith/Library of Congress 

Powerful supershear earthquakes, once considered rare, are much more common than previously thought, according to a study led by UCLA geophysicists and published in Nature Geoscience.

The scientists analyzed all 6.7-or-greater magnitude strike-slip earthquakes worldwide since 2000 — there were 87 in all — and identified 12 of the supershear type, or about 14%. (Four of those earthquakes were previously unreported.)

That percentage is more than double what scientists expected; until now less than 6% of strike-slip earthquakes had been identified as supershear.

Strike-slip earthquakes occur when the edges of two tectonic plates rub sideways against each other. Supershear quakes are a subtype of that group that are caused when faults beneath the surface rupture faster than shear waves — the seismic waves that shake the ground back and forth — can move through rock. The effect corrals energy that is then released violently; the effect can be compared to a sonic boom.

As a result, supershear earthquakes tend to cause more shaking, and are potentially more destructive, than other earthquakes that have the same magnitude.

Durable, Inexpensive Catalyst Reduces Carbon Footprint of Ammonia Production

To reduce the energy requirements of the Haber-Bosch process, which converts nitrogen and hydrogen to ammonia, researchers from Tokyo Tech have developed a metal nitride catalyst containing an active metal (Ni) on a lanthanum nitride support that is stable in presence of moisture. Since the catalyst doesn't contain ruthenium, it presents an inexpensive option for reducing the carbon footprint of ammonia production.

The Haber-Bosch process, which is commonly used to synthesize ammonia (NH3)–the foundation for synthetic nitrogen fertilizers–by combining hydrogen (H2) and nitrogen (N2) over catalysts at high pressures and temperatures, is one of the most important scientific discoveries that has helped improve crop yields and increase food production globally.

However, the process requires high fossil fuel energy inputs due to its requirements of high temperatures and pressure. Hydrogen used for this process is produced from natural gas (mainly methane). This hydrogen-producing process is energy-consuming and accompanies huge emissions of carbon dioxide. To overcome these issues, various catalysts have been developed to allow the reaction to proceed under milder conditions using hydrogen produced by water electrolysis via renewable energy. Among them are nitride-based catalysts that contain active metal nanoparticles like nickel and cobalt (Ni, Co) loaded on lanthanum nitride (LaN) supports. In these catalysts, both the support and the active metal are involved in the production of NH3. The active metal splits the H2 while the LaN support contains nitrogen vacancies and nitrogen atoms in its crystal structure that absorb and activate nitrogen (N2). While these catalysts are inexpensive (since they avoid using ruthenium, which is costly), their catalytic performance is degraded in the presence of moisture, with the LaN support transforming into lanthanum hydroxide (La(OH)3).

New catalyst can turn smelly hydrogen sulfide into a cash cow

An illustration of the light-powered, one-step remediation process for hydrogen sulfide gas made possible by a gold photocatalyst created at Rice University.
Image Credit: Halas Group/Rice University

Hydrogen sulfide gas has the unmistakable aroma of rotten eggs. It often emanates from sewers, stockyards and landfills, but it is particularly problematic for refineries, petrochemical plants and other industries, which make thousands of tons of the noxious gas each year as a byproduct of processes that remove sulfur from petroleum, natural gas, coal and other products.

In a published study in the American Chemical Society’s high-impact journal ACS Energy Letters, Rice engineer, physicist and chemist Naomi Halas and collaborators describe a method that uses gold nanoparticles to convert hydrogen sulfide into high-demand hydrogen gas and sulfur in a single step. Better yet, the one-step process gets all its energy from light. Study co-authors include Rice’s Peter Nordlander, Princeton University’s Emily Carter and Syzygy Plasmonics’ Hossein Robatjazi.

“Hydrogen sulfide emissions can result in hefty fines for industry, but remediation is also very expensive,” said Halas, a nanophotonics pioneer whose lab has spent years developing commercially viable light-activated nanocatalysts. “The phrase ‘game-changer’ is overused, but in this case, it applies. Implementing plasmonic photocatalysis should be far less expensive than traditional remediation, and it has the added potential of transforming a costly burden into an increasingly valuable commodity.”

Bulking Up to Beat Bacteria

The inhibitor-binding site of the wild-type MexB pump. (a) The crystal structure of the inhibitor ABI-PP bound to the MexB trimer. Three MexB monomers are shown in green, blue, and red, representing the access, binding, and extrusion monomer, respectively. ABI-PP is shown as a yellow space-filling model. (b) A close-up view of the inhibitor binding site. The substrate translocation pathway is shown as a solid gray surface. The proximal and distal binding pockets are indicated in green and blue circles, respectively. The inhibitor binding pit is shown as a red surface. The ABI-PP molecule is represented as a yellow stick model. (c) A detailed view of the inhibitor-binding site. Carbon atoms of ABI-PP are indicated in yellow while amino acid residues are indicated in green. The classification of these amino acids is shown on the right side of the panel.
Image Credit: 2022 Yamasaki et al., Spatial Characteristics of the Efflux Pump MexB Determine Inhibitor Binding, Antimicrobial Agents and Chemotherapy

The medical profession is in the midst of losing an arms race. Bacterial antibiotic resistance doesn’t just threaten our ability to treat infection but our ability to carry out any treatment where infection is a risk. This includes a raft of life-saving surgeries ranging from coronary bypass operations to organ transplantation. In fact, the number of new antimicrobials being developed is declining each year. Understanding how bacteria resist the influence of antibiotics is essential to winning this arms race: it is time to make up ground.

In a study published this month in Antimicrobial Agents and Chemotherapy, researchers at Osaka University have produced new insights into the structure of a particular bacterial protein known as an efflux pump. This protein is involved in antibiotic resistance and its structure influences the ability of drugs to target it.

New MicroBooNE analysis takes a closer look at the sterile neutrino

MicroBooNE features state-of-the-art particle detection techniques and technology. The experiment studies neutrino interactions and is probing models of a theorized fourth neutrino called the sterile neutrino.
Photo Credit: Reidar Hahn, Fermilab

A new result from the MicroBooNE experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory probes the Standard Model — scientists’ best theory of how the universe works. The model assumes there are three kinds of neutrinos. Yet for more than two decades, a proposed fourth kind of neutrino has remained a promising explanation for anomalies seen in earlier physics experiments. Finding the theorized sterile neutrino would be a major discovery and radical shift in our understanding of the universe.

The new analysis published in arXiv compares the experiment’s data to a model with a fourth, sterile neutrino to test their compatibility. MicroBooNE scientists found no evidence of the long-sought sterile neutrino in the parameter range explored.

The possibility that sterile neutrinos caused the yet-unexplained anomalies reported by previous experiments still remains. These include measurements by the Liquid Scintillator Neutrino Detector at Los Alamos National Laboratory, the MiniBooNE experiment at Fermilab, and several radiochemical and nuclear reactor neutrino experiments.

“This is the first time we’ve checked whether our data fit a specific sterile-neutrino model,” said Matt Toups, a Fermilab scientist and co-spokesperson for MicroBooNE. “We’ve excluded large sections of the sterile neutrino parameter space allowed by LSND. But there are still corners where a sterile neutrino could potentially be hiding.”

Reprogramming of immune cells shown to fight off melanoma

Illustration showing how miniature artificial protocells loaded with anti-microRNA-223 cargo can reprogram cancer-associated macrophages in larval and adult zebrafish leading them to be more pro-inflammatory and thus able to drive melanoma shrinkage
Image Credit: Paco Lopez Cuevas

A new way of reprogramming our immune cells to shrink or kill off cancer cells has been shown to work in the otherwise hard to treat and devastating skin cancer, melanoma. The University of Bristol-led discovery, published in Advanced Science today [31 October], demonstrates a new way to clear early stage pre-cancerous and even late-stage tumor cells.

Using miniature artificial capsules called protocells designed to deploy reprogramming cargoes that are taken up by inflammatory cells (white blood cells), the scientists show they were able to transform these cells into a state that makes them more effective at slowing down the growth and killing of melanoma cells. They showed that this was possible for both animal and human immune cells.

The study is the first to test the capacity of a protocell to deliver cargoes for reprogramming immune cells and offers a promising novel target for the development of cancer immunotherapies.

Paul Martin, Professor of Cell Biology in the School of Biochemistry at the University of Bristol and one of the study's lead authors explained what happens when our immune system comes into contact with cancer cells: "Our immune cells have a surveillance capacity which enables them to detect pre-cancerous cells arising at any tissue site in the body. However, when immune cells encounter cancer cells, they are often subverted by the cancer cells and instead tend to nourish them and encourage cancer progression. We wanted to test whether it might be possible to reprogram our immune system to kill these cells rather than nurture them."

New Tech Solves Longstanding Challenges for Self-Healing Materials

3D printed thermoplastic on woven-carbon fiber reinforcement.
Credit: North Carolina State University

Engineering researchers have developed a new self-healing composite that allows structures to repair themselves in place, without having to be removed from service. This latest technology resolves two longstanding challenges for self-healing materials, and can significantly extend the lifespan of structural components such as wind-turbine blades and aircraft wings.

“Researchers have developed a variety of self-healing materials, but previous strategies for self-healing composites have faced two practical challenges,” says Jason Patrick, corresponding author of the research paper and an assistant professor of civil, construction and environmental engineering at North Carolina State University.

“First, the materials often need to be removed from service in order to heal. For instance, some require heating in an oven, which can’t be done for large components or while a given part is in use. Second, self-healing only works for a limited period. For example, the material might be able to heal a few times, after which its self-repairing properties would significantly diminish. We’ve come up with an approach that addresses both of those challenges in a meaningful way, while retaining the strength and other performance characteristics of structural fiber-composites.”

Largest Potentially Hazardous Asteroid Detected in Eight Years

Twilight observations with the U.S. Department of Energy-fabricated Dark Energy Camera at Cerro Tololo Inter-American Observatory in Chile, a program of NSF’s NOIRLab, have enabled astronomers to spot three near-Earth asteroids, or NEAs, hiding in the glare of the sun. These NEAs are part of an elusive population that lurks inside the orbits of Earth and Venus. One of the asteroids is the largest object that is potentially hazardous to Earth to be discovered in the last eight years.
Image Credit: DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA/J. da Silva/Spaceengine

Twilight observations with the US Department of Energy-fabricated Dark Energy Camera at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF's NOIRLab, have enabled astronomers to spot three near-Earth asteroids (NEA) hiding in the glare of the Sun. These NEAs are part of an elusive population that lurks inside the orbits of Earth and Venus. One of the asteroids is the largest object that is potentially hazardous to Earth to be discovered in the last eight years.

An international team using the Dark Energy Camera (DECam) mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF’s NOIRLab, has discovered three new near-Earth asteroids (NEAs) hiding in the inner Solar System, the region interior to the orbits of Earth and Venus. This is a notoriously challenging region for observations because asteroid hunters have to contend with the glare of the Sun.

By taking advantage of the brief yet favorable observing conditions during twilight, however, the astronomers found an elusive trio of NEAs. One is a 1.5-kilometer-wide asteroid called 2022 AP7, which has an orbit that may someday place it in Earth’s path. The other asteroids, called 2021 LJ4 and 2021 PH27, have orbits that safely remain completely interior to Earth’s orbit. Also, of special interest to astronomers and astrophysicists, 2021 PH27 is the closest known asteroid to the Sun. As such, it has the largest general-relativity effects [1] of any object in our Solar System and during its orbit its surface gets hot enough to melt lead.

Ghost of a giant star

This image shows a spectacular view of the orange and pink clouds that make up what remains after the explosive death of a massive star — the Vela supernova remnant. This detailed image consists of 554 million pixels, and is a combined mosaic image of observations taken with the 268-million-pixel OmegaCAM camera at the VLT Survey Telescope, hosted at ESO’s Paranal Observatory.   OmegaCAM can take images through several filters that each let the telescope see the light emitted in a distinct color. To capture this image, four filters have been used, represented here by a combination of magenta, blue, green and red. The result is an extremely detailed and stunning view of both the gaseous filaments in the remnant and the foreground bright blue stars that add sparkle to the image. 
Hi-Res Zoomable Image
Credit: ESO/VPHAS+ team. Acknowledgement: Cambridge Astronomical Survey Unit

A spooky spider web, magical dragons or wispy trails of ghosts? What do you see in this image of the Vela supernova remnant? This beautiful tapestry of colors shows the ghostly remains of a gigantic star, and was captured here in incredible detail with the VLT Survey Telescope, hosted at the European Southern Observatory’s (ESO’s) Paranal site in Chile.

The wispy structure of pink and orange clouds is all that remains of a massive star that ended its life in a powerful explosion around 11 000 years ago. When the most massive stars reach the end of their life, they often go out with a bang, in an outburst called a supernova. These explosions cause shock waves that move through the surrounding gas, compressing it and creating intricate thread-like structures. The energy released heats the gaseous tendrils, making them shine brightly, as seen in this image.

In this 554-million-pixel image, we get an extremely detailed view of the Vela supernova remnant, named after the southern constellation Vela (The Sails). You could fit nine full Moons in this entire image, and the whole cloud is even larger. At only 800 light-years away from Earth, this dramatic supernova remnant is one of the closest known to us.

A better way to tell which species are vulnerable

Intertidal ecosystems containing species of mussels, barnacles, and algae were one of the systems with fluctuating populations analyzed by the team. They developed a new way to detect species that are vulnerable to perturbations, such as waves and storms that affect intertidal ecosystems.
Credits: Courtesy of the researchers | Massachusetts Institute of Technology

Wildfires, floods, pollution, and overfishing are among the many disruptions that can change the balance of ecosystems, sometimes endangering the future of entire species. But evaluating these ecosystems to determine which species are most at risk, in order to focus preservation actions and policies where they are most needed, is a challenging task.

Most such efforts assume that ecosystems are essentially in a state of equilibrium, and that external perturbations cause a temporary shift before things eventually return to that equilibrium state. But that assumption fails to account for the reality that ecosystems are often in flux, with the relative abundances of their different components shifting on timetables of their own. Now, a team of researchers at MIT and elsewhere have come up with a better, predictive way of evaluating these systems in order to rank the relative vulnerabilities of different species, and to detect species that are under threat but could otherwise go unnoticed.

Contrary to conventional ways of making such rankings today, they found, the species with the lowest population numbers or the steepest decline in numbers — criteria typically used today — are sometimes not the ones most at risk.

The findings are reported today in the journal Ecology Letters, in a paper by MIT associate professor of civil and environmental engineering Serguei Saavedra, recent doctoral student Lucas Medeiros PhD ’22, and three others.