Umbrella toxin particles produced by Actinobacteria contain five spokes tipped with variable lectin domains. Here, Zhao et al. show that these lectins mediate species-specific binding to a previously unrecognized cell surface carbohydrate polymer and propose that the modular nature of umbrella particles enables bet hedging against unpredictable competitor encounters.
A new type of sensor that levitates dozens of glass microparticles could revolutionize the accuracy and efficiency of sensing, laying the foundation for better autonomous vehicles, navigation and even the detection of dark matter.
Using a camera inspired by the human eye, scientists from King’s College London believe they could track upwards of 100 floating particles in what could be one of the most sensitive sensors to date.
Levitating sensors typically isolate small particles to observe and quantify the impact of outside forces like acceleration on them. The higher the number of particles which could be disturbed and the greater their isolation from their environment, the more accurate the sensor can be.
Using sound to get objects to float works well if a single particle is levitated, but it causes multiple particles to collapse into a clump in mid-air. Physicists at the Institute of Science and Technology Austria (ISTA) have now found a way to keep them apart using charge. Their findings, published in Proceedings of the National Academy of Sciences, could find applications in materials science, robotics, and microengineering.
Who hasn’t dreamed of overcoming gravity and getting objects to hover above ground?
In 2013, Scott Waitukaitis, now an assistant professor at the Institute of Science and Technology Austria (ISTA), became interested in using acoustic levitation as a tool to study various physical phenomena. At that time, only a handful of research groups were using this technique for similar purposes.
And this isn’t the only close match. The energy signature of these gamma-rays closely matches those predicted to emerge from the annihilation of colliding WIMPs, which are predicted to have a mass around 500 times that of a proton, the ordinary matter particles found at the heart of atoms. Totani suggests there aren’t any other astronomical phenomena that easily explain the gamma-rays observed by Fermi.
“If this is correct, to the extent of my knowledge, it would mark the first time humanity has ‘seen’ dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics,” Totani said. “This signifies a major development in astronomy and physics.”
While Totani is confident that what he and his colleagues have detected is the signature of dark matter WIMPs annihilating each other at the heart of the Milky Way, the scientific community in general will require more hard evidence before the book is closed on this nearly century-old mystery.
When a system undergoes a transformation, yet an underlying physical property remains unchanged, this property is referred to as “symmetry.” Spontaneous symmetry breaking (SSB) occurs when a system breaks out of this symmetry when it is most stable or in its lowest-possible energy state.
Recently, physicists realized that a new type of SSB can occur in open quantum systems, systems driven by quantum mechanical effects that can exchange information, energy or particles with their surrounding environment. Specifically, they realized that the symmetry in these systems can be “strong” or “weak.”
A strong symmetry entails that both the open system and its surrounding environment individually obey the symmetry. In contrast, a weak symmetry takes place when the system and the environment only follow a symmetry when they are taken together.
For nearly a century, scientists have understood how crystalline materials—such as metals and semiconductors—bend without breaking. Their secret lies in tiny, line-like defects called dislocations, which move through an orderly atomic lattice and carry deformation with them.
At the heart of this theory is a geometric quantity known as the Burgers vector, experimentally observed for the first time in the 1950s, which precisely measures how much the lattice is distorted by a dislocation. This concept became one of the cornerstones of modern materials science.
Glasses, however, have always stood apart. From window glass and polymers to metallic glasses and many soft materials, glasses lack the regular atomic structure of crystals. Their particles are arranged randomly, frozen into disordered atomic configurations.
In physical systems, transport takes many forms, such as electric current through a wire, heat through metal, or even water through a pipe. Each of these flows can be described by how easily the underlying quantity—charge, energy, or mass—moves through a material.
Normally, collisions and friction lead to resistance causing these flows to slow down or fade away. But in a new experiment at TU Wien, scientists have observed a system where that doesn’t happen at all.
By confining thousands of rubidium atoms to move along a single line using magnetic and optical fields, they created an ultracold quantum gas in which energy and mass move with perfect efficiency. The results, now published in the journal Science, show that even after countless collisions, the flow remains stable and undiminished, thus revealing a kind of transport that defies the rules of ordinary matter.
Maria Strømme, a materials science professor at Uppsala University, outlines a new theoretical model in AIP Advances that begins with a central claim: consciousness is fundamental field, and time, space, and matter develop from it.
Her paper treats conscious experience not as a late add-on, but as the basic “stuff” that reality is made of. In that picture, your brain, your body, and even space and time grow out of a deeper kind of “mind” that fills the whole universe.
Most neuroscientists still ask, “How does the brain produce consciousness?”
Speed matters. When an X-ray photon excites an atom or ion, making a core electron jump onto a higher energy level, a short-lived window of opportunity opens. For just a few femtoseconds, before an electron fills the void in the lower energy level, a second photon has the chance to be absorbed by another core electron, creating a doubly excited state.
Using 5,000 intense X-ray flashes per second, generated by the European XFEL, an international team of scientists has investigated such double core-hole states in highly ionized krypton, using photons that all had nearly the same energy or color.
For their experiments, scientists from European XFEL and the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg as well as six other institutions across Germany, Italy, Portugal, and the United States, used highly charged krypton, Kr26+, lacking all but ten of its electrons.