Activated CD8 T cells transiently produce IL-21, creating highly proliferative killers that help control chronic viral infection.
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A crossvertebrate brain protein interaction map identifies conserved neural and nonneural complexes
Dang et al. use co-fractionation and immunoprecipitation mass spectrometry to map protein interactions conserved across vertebrate brains. This resource, dubbed VerteBrain, offers insights into brain protein function and new links between proteins and disease, identifying candidate genes and pathways involved in epilepsy, deafness, and developmental disorders.
A temperature dial for more realistic quantum simulations
Scientists from Rice University in the U.S. have developed a way to precisely tune the temperature inside a trapped-ion simulator. The breakthrough means they will be able to run quantum simulations at precise temperatures that better reflect real-world conditions.
Trapped-ion simulators are quantum devices that isolate charged particles inside a sealed vacuum chamber, using electric fields to hold them in place. They mimic and study complex quantum systems, such as chemical reactions or exotic materials, that are too difficult for ordinary computers to calculate.
Temperatures inside these devices are typically kept as close as possible to absolute zero so that thermal motion does not disrupt calculations or cause errors. But researchers lacked a suitable way to set the temperature without accidentally changing how fast the system loses energy. This meant that studies were mostly stuck using absolute zero or uncontrolled high temperatures.
New approach to cleaning the inner walls of a fusion system removes another obstacle to near-endless energy
Fusion systems need inner walls that can withstand extreme heat. One promising solution uses liquid lithium to protect the walls, held like water in a sponge made of the exceptionally strong metal tungsten. An advanced manufacturing process can be used to make tungsten into sponge-like wall tiles with lots of pores for flowing liquid lithium. But this process also leaves the tungsten contaminated with other materials, such as carbon, oxygen or nitrogen.
When exposed to liquid lithium, the carbon and oxygen react to form solids that can plug the holes in the tungsten, preventing the lithium from flowing properly. Even if the tungsten were cleaned at the end of the manufacturing process, it would become recontaminated when the tiles are exposed to air during installation.
Now researchers from the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), Princeton University and Pennsylvania State University have found a clever way to clean those tiles after they are installed and sealed inside the fusion system—in vacuum chambers from which the air has been removed. The advance, which uses heat combined with particles from a neon plasma to knock contaminants out of tiles, could help future fusion systems run better with liquid lithium.
Pushing the boundaries of ultracold neutral plasmas
Using a combination of laser cooling techniques and strong magnetic fields, researchers at Colorado State University have for the first time created an ultracold neutral plasma with electrons cooled to temperatures measured to be within one degree Kelvin.
The work, highlighted in Physics of Plasmas, outlines an approach to better validate theory and refine models of this common state of matter under these and other extreme conditions.
Among many potential applications, the findings will be helpful for the future development of fusion energy systems and the study of astrophysical systems, such as white dwarf stars.
Molecular orbitals imaged in 3D, opening path to femtosecond videos
One of the most famous and intriguing results of quantum mechanics is the finding that fundamental particles, such as electrons, cannot be pinned down to one single location. Instead, a particle is described by its “wavefunction,” which allows researchers to derive probability distributions—a sort of mathematical map that shows the possibilities—of fundamental properties such as its position and momentum. In particular, the electron wavefunctions within a molecule, known as “molecular orbitals,” carry information about how the molecule interacts with its surroundings. For example, they show how it may absorb light or how a chemical reaction might take place.
As a consequence, knowledge of the complete three-dimensional wavefunction is highly desirable, but imaging the wavefunction has proven to be a major experimental challenge. An interdisciplinary research team at the University of Göttingen has now managed to image the three-dimensional wavefunction of a nanometer-sized organic molecule. They overcame the limitations by combining state-of-the-art photoelectron spectroscopy with powerful mathematical algorithms. The results are published in Nature Communications.
Women with narcissistic tendencies may struggle with forgiveness
Narcissism is associated with selfishness and other negative traits like a grandiose sense of self-importance, a constant need for admiration and a lack of empathy for others. So it may not be surprising that narcissists tend to have a hard time with behaviors associated with better mental health and healthy relationships, like forgiveness. But a new study, published in the Journal of Behavior Therapy and Experimental Psychiatry, explores how people with a particular type of narcissism automatically respond to interpersonal offenses by measuring their tendencies to seek revenge, avoid the person who offended them or act in a benevolent manner.
Past findings on narcissism and forgiveness have been mixed, partly because they treated narcissism as a single trait. However, most researchers agree that narcissism is not a single trait. The authors of the new study say that it is commonly divided into two higher-order domains: grandiose and vulnerable narcissism.
These domains are further refined into antagonistic narcissism, defined by hostility and reactive self-defensiveness; agentic extraversion, defined by self-promoting and self-enhancement tendencies; and narcissistic neuroticism, defined by insecurity and social withdrawal. The new study focuses on antagonistic narcissism, which involves traits such as entitlement, hostility and exploiting others.
First measurement of antineutrinos from spent nuclear fuel confirms emissions persist after reactor shutdown
Even when the lights go out and nuclear reactors are turned off, the story inside the reactor core still has a great deal to tell. Radioactive, long-lived fission products continue to decay for months or even years, producing a faint flux of a specific type of particle known as antineutrinos. (Anti)neutrinos are the lightest and most elusive known particles in the universe, allowing them to escape unhindered from both the reactor and the surrounding shielding.
Researchers in the Double Chooz collaboration have now measured this residual antineutrino emission for the first time. The study, which was published in Physical Review Letters, was led by Anthony Onillon and Thierry Lasserre from the Max-Planck-Institut für Kernphysik (MPIK) in Heidelberg, Germany.
The results demonstrate that antineutrino detectors can probe nuclear reactors even during shutdown periods, opening new perspectives for reactor monitoring, nuclear safety and safeguards.