The jet coming out of the center of M87 is seven orders of magnitude — tens of millions of times — larger than the event horizon, or surface of the black hole itself. The bright burst of high-energy emission was well above the energies typically detected by radio telescopes from the black hole region. The flare lasted about three days and probably emerged from a region less than three light-days in size, or a little under 15 billion miles.

A gamma ray is a packet of electromagnetic energy, also known as a photon. Gamma rays have the most energy of any wavelength in the electromagnetic spectrum and are produced by the hottest and most energetic environments in the universe, such as regions around black holes. The photons in M87’s gamma ray flare have energy levels up to a few teraelectronvolts. Teraelectronvolts are used to measure the energy in subatomic particles and are equivalent to the energy of a mosquito in motion. This is a huge amount of energy for particles that are many trillion times smaller than a mosquito. Photons with several teraelectronvolts of energy are vastly more energetic than the photons that make up visible light.

As matter falls toward a black hole, it forms an accretion disk where particles are accelerated due to the loss of gravitational potential energy. Some are even redirected away from the black hole’s poles as a powerful outflow, called “jets,” driven by intense magnetic fields. This process is irregular, which often causes a rapid energy outburst called a “flare.” However, gamma rays cannot penetrate Earth’s atmosphere. Nearly 70 years ago, physicists discovered that gamma rays can be detected from the ground by observing the secondary radiation generated when they strike the atmosphere.

“We still don’t fully understand how particles are accelerated near the black hole or within the jet,” said Weidong Jin, a postdoctoral researcher at UCLA and a corresponding author of a paper describing the findings published by an international team of authors in Astronomy & Astrophysics. “These particles are so energetic, they’re traveling near the speed of light, and we want to understand where and how they gain such energy. Our study presents the most comprehensive spectral data ever collected for this galaxy, along with modeling to shed light on these processes.”

Jin contributed to analysis of the highest energy part of the dataset, called the very-high-energy gamma rays, which was collected by VERITAS — a ground-based gamma-ray instrument operating at the Fred Lawrence Whipple Observatory in southern Arizona. UCLA played a major role in the construction of VERITAS — short for Very Energetic Radiation Imaging Telescope Array System — participating in the development of the electronics to read out the telescope sensors and in the development of computer software to analyze the telescope data and to simulate the telescope performance. This analysis helped detect the flare, as indicated by large luminosity changes that are a significant departure from the baseline variability.

More than two dozen high-profile ground- and space-based observational facilities, including NASA’s Fermi-LAT, Hubble Space Telescope, NuSTAR, Chandra and Swift telescopes, together with the world’s three largest imaging atmospheric Cherenkov telescope arrays (VERITAS, H.E.S.S. and MAGIC) joined this second EHT and multi-wavelength campaign in 2018. These observatories are sensitive to X-ray photons as well as high-energy and very-high-energy gamma-rays, respectively.

One of the key datasets used in this study is called spectral energy distribution.

“The spectrum describes how energy from astronomical sources, like M87, is distributed across different wavelengths of light,” Jin said. “It’s like breaking the light into a rainbow and measuring how much energy is present in each color. This analysis helps us uncover the different processes that drive the acceleration of high-energy particles in the jet of the supermassive black hole.”

Further analysis by the paper’s authors found a significant variation in the position and angle of the ring, also called the event horizon, and the jet position. This suggests a physical relationship between the particles and the event horizon, at different size scales, influences the jet’s position.

“One of the most striking features of M87’s black hole is a bipolar jet extending thousands of light years from the core,” Jin said. “This study provided a unique opportunity to investigate the origin of the very-high-energy gamma-ray emission during the flare, and to identify the location where the particles causing the flare are being accelerated. Our findings could help resolve a long-standing debate about the origins of cosmic rays detected on Earth.”

Cancer immunotherapy has revolutionised treatment for patients, whereby the body’s own immune system is harnessed to destroy cancer cells.

Typically, several molecules restrain the ability of T cells to target cancer cells and developing approaches to limit this restraining effect can lead to improved effectiveness of cancer immunotherapy.

Research published in Science Immunology has determined the structure of how an inhibitory molecule, LAG3, interacts with its main ligand and provides a new targeted approach to improving the effectiveness of immunotherapy for certain forms of cancer.

The publication is the first to show the crystal structure of a human LAG-3/HLA-II complex and provides a better foundation for development of blocking LAG-3 therapeutics.

Led by Professor Jamie Rossjohn at Monash University’s Biomedicine Discovery Institute (BDI), in Melbourne, Australia, in collaboration with Immutep, this research resolves how the human LAG-3 receptor binds to HLA II molecules.

First author Dr Jan Petersen said: “The way the PD-1 and CTLA-4 immune checkpoint molecules bind to their respective ligands has been resolved for many years.

“However, the resolution of the interface between another important checkpoint molecule, LAG-3, and its main ligands, HLA-II molecules, has remained elusive.

“Solved using data collected at the Australian Synchrotron, a structure of a LAG-3/HLA-II complex provides a structural foundation to harness rationally for future development of antibodies and small molecule therapeutics designed to block LAG-3 activity.”

Dr Frédéric Triebel, Immutep’s CSO, added: “These findings add to the strong foundation of our work with Professor Rossjohn and his team to develop a deeper understanding of the structure and function of the LAG-3 immune control mechanism, particularly as it relates to our anti-LAG-3 small molecule program.”

The struggle of our cells

Imagine trying to fit two meters of rope into a space much smaller than the tip of a needle — that’s the challenge every cell in your body faces when packing its DNA into its tiny nucleus. To achieve this, nature employs ingenious strategies, like twisting the DNA into coils of coils, so-called ‘supercoils’ (see pictures for a visualisation) and wrapping it around special proteins for compact storage.

Small DNA loops regulate chromosome functions

However, compaction isn’t enough. Cells also need to regulate the chromosome structure to enable its function. For example, when genetic information needs to be accessed, the DNA is locally read off. In particular when it’s time for a cell to divide, the DNA must first unpack, duplicate, and then properly separate into two new cells. Specialised protein machines called SMC complexes (Structural Maintenance of Chromosomes) play a critical role in these processes. Just a few years ago, scientists at Delft and other places discovered that these SMC proteins are molecular motors that make long loops in our DNA, and that these loops are the key regulators of chromosome function.

A new twist

In the lab of Cees Dekker at TU Delft, postdocs Richard Janissen and Roman Bath now provide clues that help to crack this puzzle. They deloped a new way to use ‘magnetic tweezers’ by which they could watch individual SMC proteins make looping steps in DNA. Importantly, they were also able to resolve if the SMC protein would change the twist in the DNA. And strikingly, the team found that it did: the human SMC protein cohesin does indeed not only pull DNA into a loop, but also twists the DNA in a left-handed way by 0.6 turns in each step of creating the loop.

A glimpse into the evolution of SMC proteins

What’s more, the team found that this twisting action isn’t unique to humans. Similar SMC proteins in yeast behave the same way. Strikingly, all the various types of SMC proteins from human and yeast add the same amount of twist — they turn DNA 0.6 times at every at every DNA loop extrusion step. This shows that the DNA extrusion and twisting mechanisms stayed the same for very long times during evolution. No matter whether DNA is looped in humans, yeast, or any other cell — nature employs the same strategy.

Essential clues

These new findings will provide essential clues for resolving the molecular mechanism of this new type of motor. Additionally, they make clear that DNA looping also affects the supercoiling state of our chromosomes, which directly affects processes like gene expression. Finally, these SMC proteins are related to various diseases such as Cornelia de Lange Syndrome, and a better understanding of these processes is vital for tracking down the molecular origins of these serious illnesses.

The air around us contains a powerful solution for making agriculture more sustainable. Researchers at Stanford University and King Fahd University of Petroleum and Minerals in Saudi Arabia have developed a prototype device that can produce ammonia — a key fertilizer ingredient — using wind energy to draw air through a mesh. The approach they developed, if perfected, might eliminate the need for a century-old method that produces ammonia by combining nitrogen and hydrogen at high pressures and temperatures. The older method consumes 2% of global energy and contributes 1% of annual carbon dioxide emissions from its reliance on natural gas.

The study, published Dec. 13 in Science Advances, involved the first on-site — rather than in a lab — demonstration of the technology. The researchers envision someday integrating the device into irrigation systems, enabling farmers to generate fertilizer directly from the air.

“This breakthrough allows us to harness the nitrogen in our air and produce ammonia sustainably,” said study senior author Richard Zare, the Marguerite Blake Wilbur Professor in Natural Science in the Stanford School of Humanities and Sciences. “It’s a significant step toward a decentralized and eco-friendly approach to agriculture.”

A cleaner alternative

In preparation for designing their device, the researchers studied how different environmental factors — like humidity, wind speed, salt levels, and acidity — affect ammonia production. They also looked at how the size of water droplets, the concentration of the solution, and the contact of water with materials that do not dissolve in water impact the process. Lastly, they tested the best mix of iron oxide and an acid polymer with fluorine and sulfur to determine the ideal conditions for producing ammonia and understand how these catalyst materials interact with water droplets.

The Stanford team’s process makes ammonia cleanly and inexpensively and utilizes the surrounding air to get nitrogen and hydrogen from water vapor. By passing air through a mesh coated with catalysts to facilitate the necessary reaction, the researchers produced enough ammonia with a sufficiently high concentration to serve as a hydroponic fertilizer in greenhouse settings. Unlike traditional methods, the new technique operates at room temperature and standard atmospheric pressure, requiring no external voltage source to be attached to the mesh. Farmers could run the portable device onsite, eliminating the need to purchase and ship fertilizer from a manufacturer.

“This approach significantly reduces the carbon footprint of ammonia production,” said study lead author Xiaowei Song, a chemistry research scientist at Stanford.

In laboratory experiments, the team demonstrated further potential by recycling water through a spraying system, achieving ammonia concentrations sufficient to fertilize plants grown in a greenhouse after just two hours. By incorporating a filter made from a microporous stone material, this approach could produce enough ammonia to support broader agricultural applications.

A future without fossil fuels

The device is two to three years away from being market-ready, according to study co-author Chanbasha Basheer of King Fahd University of Petroleum and Minerals. In the meantime, the researchers plan to use increasingly large mesh systems to produce more ammonia. “There is a lot of room to develop this,” Basheer said.

Ammonia’s importance extends beyond fertilizers. As a clean energy carrier, it can store and transport renewable energy more efficiently than hydrogen gas due to its higher energy density. The innovation positions ammonia as a linchpin in decarbonizing industries like shipping and power generation.

“Green ammonia represents a new frontier in sustainability,” Zare said. “This method, if it can be scaled up economically, could drastically reduce our reliance on fossil fuels across multiple sectors.”

The study was funded by the U.S. Air Force Office of Scientific Research and King Fahd University of Petroleum and Minerals.

The team used sound wave, known as seismic, data to reveal Ice Age landforms buried beneath almost 1 km of mud in the North Sea. The results, reported in the journal Science Advances, suggest that the landforms were produced about 1 million years ago, when an ice sheet centred over Norway extended towards the British Isles.

This is important because the timing of this ice advance corresponds to a period of global cooling called the Mid-Pleistocene Transition.

Glacial landforms reveal how past ice sheets responded to changes in climate, which can help to make better predictions about how today’s ice sheets will respond to climate warming. A challenge is that glacial landforms are often buried beneath thick layers of sediment, preventing their identification.

Dr Christine Batchelor, Senior Lecturer in Physical Geography, Newcastle University, played a key role in the research by helping to map and interpret the landforms. “To fully understand the linkages between ice sheets and climate, we need to study how past ice sheets responded to long-term changes in climate,” said Dr Batchelor. “Using modern seismic data, our results suggests that ice sheets in northwest Europe expanded significantly in response to climate cooling about 1 million years ago.”

Dr Dag Ottesen from the Geological Survey of Norway, the paper’s lead author, said: “This study was made possible by the availability of 3D seismic data from the North Sea, which allowed us to examine the buried landforms in striking detail.”

3D seismic technology was developed to assess sediment suitability to host oil and gas or renewable infrastructures. However, this same data can be used to study buried landforms produced by glacial processes.

The mapped landscape includes streamlined features that were carved beneath the former ice sheet and ridges that record the imprint of the ice sheet as it started to retreat. Despite their ancient age, the landforms have striking resemblance to similar features produced by ice sheets much more recently.

The buried landforms provide new knowledge about the mechanisms by which ice sheets retreat. In order for such subdued landforms to remain unmodified, the former ice sheet must have retreated rapidly by lift-off and floatation of its frontal margin.

In addition to glacial landforms, the researchers also found elongated furrows incised into the former seabed, which they interpreted to have been produced by strong ocean currents. These landforms are even more deeply buried than the glacial landforms, showing that they were produced prior to the advance of the ice sheet.

“With our high-resolution data, we can see that the shape and size of the furrows is consistent with an origin as ocean current furrows,” said Dr Ottesen. “This differs from previous interpretations of these features as glacial landforms, re-writing our understanding of North Sea glacial history.”

By providing a new level of detail about the buried landforms, the findings shed light into the evolution of the North Sea in our recent geological past. The study shows that the North Sea was characterised by strong ocean currents prior to about 1 million years ago, after which it became more directly influenced by ice sheets.

The research team acknowledge that a limitation of the study is a lack of data about the precise age of the landforms.

“A wealth of seismic data are now available for the North Sea,” said Dr Batchelor. “The next step is to acquire long sediment cores that can allow researchers to better understand the timing of glacial events.”

Other co-authors are Helge Løseth at Equinor ASA, Trondheim and Harald Brunstad at Aker BP ASA, Trondheim.

The Safe Drinking Water Act requires monitoring by public water utilities, but those samples are taken outside property lines of individual households. Once inside a home, microbial communities can change and evolve in ways that are generally not monitored or even understood.

Fangqiong Ling, an assistant professor of energy, environmental and chemical engineering in the McKelvey School of Engineering at Washington University in St. Louis, is working to change that, along with her colleagues and students within the school’s cluster of water quality researchers.

For a paper published Dec. 10 in Nature Water, Ling and colleagues shared results from sampling the bathroom faucets of eight households in the St. Louis metro area. They sampled the homes for seven days to see the flow and change of different bacteria populations. They found that, though houses generally shared major categories of bacteria, down to the species level, there was wide variation from house to house.

“The houses have their own unique signature compared to the rest,” Ling said.

All public tap water is subject to stringent treatment and disinfectants, so the number of microbial cells they detected was very small — another challenge for monitoring.

But the survivors they find are tough. The researchers anticipated seeing antibiotic resistance genes in tap water microbiomes, and they did find that pattern.

Using the same common disinfectant means that a recognizable group of microbes can potentially pick up resistance to that disinfectant. The researchers found a pattern of that “resistome” across households. But what accounts for the huge variety in species?

Computer modeling suggests that microbes initially establish their communities through both deterministic and stochastic processes, meaning random events, which could account for why there is huge variation at the species level, household to household.

For household water, these processes could involve the random timing for microbes’ arrival at the house, their growth dynamics and a variety of factors that aren’t yet understood.

The research aims to be able to monitor, anticipate and prevent outbreaks of opportunistic pathogens and bacteria that spread disease. This kind of monitoring is under development for large buildings and institutions such as hospitals, but it’s scarce for individual households.

“Houses are still the place where the majority of our interactions with water take place, so we want to study households,” Ling said.

While researchers found illness-causing pathogens or bacteria (in small quantities) in houses, it doesn’t necessarily mean that household water is unsafe — but public health regulators should keep a closer watch, she said.

Ling’s PhD student Lin Zhang, lead author on the Nature Water paper, has set up a way to crowd-source the sampling by recruiting high school students to serve as “community scientists.” Those students collected samples from about 100 households in the St. Louis metro area, data Zhang is analyzing for her final PhD project.

While plumbing-associated bacteria are generally harmless, the resistance genes they carry can be transferred to pathogens when individuals are undergoing antibiotic treatments. Because people have frequent contact with these bacteria through activities like showering and using water, there is a strong incentive to better understand the microbiome and “resistome” in plumbing systems, as well as how they interact with humans.

In the meantime, Zhang is gratified that she gets to do research that can have a local benefit and to work with students.

“I like that we were able to give high school students a glimpse into real-world research and the scientific method,” she said. “Hopefully, this might motivate them to pursue a future in environmental engineering.”

Fixing the pipes

This fall, the Environmental Protection Agency instituted a rule that all municipalities that provide water will be required to replace lead pipes within the next decade. With the changeover in infrastructure, there also may be opportunities to improve monitoring beyond metals and institute mitigation measures for microplastics and the microbiome.

It’s all “on tap” for Dan Giammar, the Walter E. Browne Professor of Environmental Engineering, who is heading up a number of projects to monitor and improve drinking water sources over the next few years.

“Aspects of drinking water quality that can change between the treatment plant and the customer’s tap have been frustratingly difficult to monitor,” Giammar said. “This innovative work provides new insights into how microbes grow and what microbes are present in premise plumbing.”

As Ling and Zhang delve into better testing of household plumbing, more questions will likely arise because when it comes to microbial life, nothing is as it seems.

“The more houses we sample, the more diversity we’re seeing,” Ling said. This work was supported by a McKelvey School of Engineering Startup Fund and a Ralph E. Powe Junior Faculty Enhancement Award by the Oak Ridge Associated Universities to F.L. This research was also partially supported by the Division of Chemical, Bioengineering, Environmental and Transport Systems (CBET) of the National Science Foundation under award 2047470 to F.L.