Scientists obtain detailed maps of earthquake-triggering high-pressure subsurface fluids

16 Oct 2025 Isabelle Dumé

A diagram of the Earth's crust in cross-section, showing how supercritical fluids and gases can escape through the (usually impermeable) seal layer at faults and cause seismic vibrations. This process occurs at the boundary between brittle and ductile layers of rock. (Courtesy: 2025 Tsuji et al. CC-BY)

Researchers in Japan and Taiwan have captured three-dimensional images of an entire geothermal system deep in the Earth’s crust for the first time. By mapping the underground distribution of phenomena such as fracture zones and phase transitions associated with seismic activity, they argue that their work could improve earthquake early-warning models. It could also help researchers develop next-generation geothermal power technologies. This technology study leader, Takeshi Tsuji of the University of Tokyo, says it has enormous potential for clean, large-scale energy production.

“With a clear three-dimensional image of where supercritical fluids are located and how they move, we can identify promising drilling targets and design safer and more efficient development plans,” Tsuji says.

 

• Metrology
 
• Research update

Memristors could measure a single quantum of resistance

09 Dec 2025 Isabelle Dumé

Metrological institutes on a chip: Efforts like this one seek to bring cutting-edge measurement-science technology and expertise from national metrological institutes directly to users. (Courtesy: INRiM)

A proposed new definition of the standard unit of electrical resistance would eliminate the need for strong magnetic fields in its measurement. The new technique is based on memristors, which are programmable resistors developed initially as building blocks for novel computing architectures, and its developers claim that it would considerably simplify the experimental apparatus required to measure a single quantum of resistance in specific applications.

Electrical resistance is a physical quantity that represents how much a material opposes the flow of electrical current. It is measured in ohms (Ω). Since 2019, when the base units of the International System of Units (SI) were most recently revised, the ohm has been defined in terms of the von Klitzing constant h/e2, where h and e are the Planck constant and the charge on an electron, respectively.

 

A simple feedback mechanism keeps flapping flyers stable when hovering

05 Dec 2025 Isabelle Dumé

Feeding in mid air: A hovering hummingbird. (Courtesy: Mike Miller, University of Cincinnati News)

Researchers in the US have shed new light on the puzzling and complex flight physics of creatures such as hummingbirds, bumblebees, and dragonflies that flap their wings to hover in place. According to an interdisciplinary team at the University of Cincinnati, the mechanism these animals deploy can be described by a straightforward, computationally basic, stable, and natural feedback mechanism that operates in real time. The work could aid the development of hovering robots, including those that could act as artificial pollinators for crops.

If you’ve ever watched a flapping insect or hummingbird hover in place – often while engaged in other activities such as feeding or even mating – you’ll appreciate how remarkable they are. To stay aloft and stable, these animals must constantly sense their position and motion and make corresponding adjustments to their wing flaps.

 

• Medical physics
 
• Blog

Bridging borders in medical physics: guidance, challenges, and opportunities

10 Dec 2025 Tami Freeman

Educational aid Global Medical Physics: A Guide for International Collaboration explores the increasing role of medical physicists in international collaborations. The book is available in paperback, hardcover, and ebook formats. An open-access ebook will be available soon. (Courtesy: CRC Press/Taylor & Francis)

As the world population ages and the incidence of cancer and cardiac disease grows alongside, there’s an ever-increasing need for reliable and effective diagnostics and treatments. Medical physics plays a central role in both of these areas – from the development of a suite of advanced diagnostic imaging modalities to the ongoing evolution of high-precision radiotherapy techniques.

But access to medical physics resources – whether equipment and infrastructure, education and training programmes, or the medical physicists themselves – is massively imbalanced around the world. In low- and middle-income countries (LMICs), fewer than 50% of patients have access to radiotherapy, with similar shortfalls in medical imaging equipment. Lower-income countries also have the fewest medical physicists per capita.

This disparity has led to growing interest in global health initiatives, with professional organizations seeking to support medical physicists in lower-income regions. Alongside medical physicists, other healthcare professionals strive to collaborate internationally across clinical, educational, and research settings.

 

• Emerging therapies
 
• Research update

Tumour-specific radiofrequency fields suppress brain cancer growth

28 Oct 2025 Tami Freeman

Clinical response MR images from a patient with glioblastoma obtained before (left) and after (right) treatment with the TheraBionic device emitting GBMF. Post-treatment scans exhibited a more heterogeneous and ill-defined enhancement pattern than the initial scans, suggestive of treatment effect rather than tumour progression. (Courtesy: CC BY 4.0/Oncotarget 10.18632/oncotarget 28770)

A research team at Wayne State University School of Medicine in the US has developed a novel treatment for glioblastoma, based on exposure to low levels of radiofrequency electromagnetic fields (RF EMF). The researchers demonstrated that the new therapy slows the growth of glioblastoma cells in vitro and, for the first time, showed its feasibility and clinical impact in patients with brain tumours.

The study, led by Hugo Jimenez and reported in Oncotarget, uses a device developed by TheraBionic that delivers amplitude-modulated 27.12 MHz RF EMF throughout the entire body, via a spoon-shaped antenna placed on the tongue. Using tumour-specific modulation frequencies, the device has already received US FDA approval for the treatment of patients with advanced hepatocellular carcinoma (HCC, a liver cancer), and its safety and effectiveness are currently being assessed in clinical trials in patients with pancreatic, colorectal, and breast cancers.

 

• Accelerators and detectors
 
• Research update

Leftover gamma rays produce medically important radioisotopes

12 Dec 2025 Isabelle Dumé

Using up some leftovers: The primary target of the host experiment sits inside the large "Crystal Ball" detector in the A2 hall at the MAMI facility in Mainz, Germany. The zinc foil (the tiny orange square at the middle back of the setup) is mounted further downstream along the same beamline, where it is irradiated by the remaining bremsstrahlung photons. (Courtesy: M Eslami)

The “leftover” gamma radiation produced when the beam of an electron accelerator strikes its target is usually discarded. Physicists have now found a new use for it: generating radioactive isotopes for diagnosing and treating cancer. The technique, which leverages an already running experiment, uses bremsstrahlung from an accelerator facility to trigger nuclear reactions in a layer of zinc foil. The products of these reactions include copper isotopes that are difficult to produce using conventional techniques, suggesting that the method could reduce costs and expand access to treatments.

Radioactive nuclides are commonly used to treat cancer, and so-called theranostic pairs are especially promising. These pairs occur when one isotope of an element provides diagnostic imaging while another delivers therapeutic radiation – a combination that enables precision tumour targeting to improve treatment outcomes.

 

Sterile neutrinos: KATRIN and MicroBooNE come up empty-handed

10 Dec 2025 Hamish Johnston

No evidence for sterile neutrinos. Entrance to the interior of KATRIN’s spectrometer during the construction phase. (Courtesy: Markus Breig/KIT)

Two major experiments have found no evidence for sterile neutrinos – hypothetical particles that could help explain some puzzling observations in particle physics. The KATRIN experiment searched for sterile neutrinos that could be produced during the radioactive decay of tritium. In contrast, the MicroBooNE experiment sought to test the effect of sterile neutrinos on the conversion of muon neutrinos into electron neutrinos.

Neutrinos are low-mass subatomic particles with zero electric charge that interact with matter only via the weak nuclear force and gravity. This makes neutrinos difficult to detect, although they are produced in large numbers by the Sun, nuclear reactors, and collisions in particle accelerators.

Neutrinos were first proposed in 1930 to explain the apparent missing momentum, spin, and energy in the radioactive beta decay of nuclei. They were first observed in 1956, and by 1975, physicists were confident that three types (flavours) of neutrino existed – electron, muon, and tau – along with their respective antiparticles.