Researchers at UC San Diego have demonstrated that a key cellular enzyme can accurately read an eight-letter genetic alphabet, doubling the four letters used by all known life on Earth. Detailed imaging revealed that RNA polymerase handles synthetic DNA letters in surprisingly similar ways to natural ones. The finding brings scientists closer to building expanded genetic systems that could perform entirely new biological functions.
Every new generation of phone display, television screen and solar panel is the result of precision optics experiments, which use lasers and other light sources to measure the optical properties of candidate materials. These experiments can take months to run, requiring scientists to meticulously angle and adjust delicate light sources, mirrors, cameras and other components in a process of careful, constant tuning that can be physically tedious and time-consuming.
But MIT scientists say the whole process of building and running an optics experiment could one day be fully automated. Taking a step toward such a future, they have developed a reconfigurable robotic optics laboratory.
The new robotic lab autonomously assembles standard optical components into desired configurations. It can then tune the angle and position of mirrors and lenses with micron-scale precision to produce beams of light with specific properties. The system can also safely dismantle an experiment and reassemble the parts into an entirely new setup.
A Stanford team has documented the first direct observation of quantum jumps of sound in a mechanical resonator, completing an arc of scientific exploration that started more than 100 years ago.
Quantum jumps—sudden transitions from one energy state to another—have been theorized since the early 1900s. Scientists first demonstrated these jumps in trapped ions in 1986 and later in photons, the fundamental particles of light, in 2007. Observing quantum jumps of sound had remained elusive, but a team led by Stanford physicist Amir Safavi-Naeini has recorded these phenomena, publishing the findings in the journal Science.
“What this study shows will allow us to move forward with developing new quantum technologies with sound,” said Safavi-Naeini, associate professor of applied physics in the Stanford School of Humanities and Sciences. “We have seen that vibrating objects can exhibit quantum behavior, which is the prerequisite for many of the operations needed by quantum computing and sensing.”
Quantum computers are no longer theoretical concepts. Today, they are being developed to tackle a range of complex problems, including exploring financial risk, modeling complex molecules and optimizing massive logistics networks. However, until now, there has been no way to benchmark the computational power of different systems on the same scale to see how they compare.
A team led by Sandia National Laboratories in the U.S. has devised a universal testing standard that provides an apples-to-apples performance measure. They put Google, IBM and Quantinuum hardware through the benchmark and not only found significant gaps between them but also discovered that current systems were still miles away from solving real-world problems.
The team calls its test Quantum Universal Operation Performance System, or QUOPS for short. It is designed to measure the size of the largest computationally relevant quantum circuits a quantum computer can successfully run, as well as the speed at which it can complete those operations.
Perfection is overrated—at least when it comes to complex systems like the power grid, food webs and advanced materials. For decades, scientists generally assumed that networks function most reliably when their individual components are as similar as possible. But real-world networks are rarely uniform.
Generators in a power grid, neurons in a brain, animals in a food web and components in a material all differ in ways that scientists traditionally treated as imperfections.
Now, Northwestern University physicists are overturning that long-held assumption.
Researchers at the University of Cambridge and the MRC Laboratory of Molecular Biology have discovered a previously unknown cellular defense system that protects the brain from abnormal glycogen accumulation, which is linked to severe neurological disorders.
In a study published this week in Nature, Professor Felix Randow and colleagues showed that a protein called RNF213 plays a key role in identifying abnormal glycogen. RNF213 attaches a small molecular tag called ubiquitin directly to defective glycogen molecules. This tag acts like a “dispose of this” signal, triggering a cellular recycling process known as autophagy to sweep away and break down the damaged energy stores.
Glycogen is the main form in which cells store glucose for energy. Its complex, highly branched structure keeps it soluble while allowing cells to rapidly mobilize glucose when energy is needed. When cells assemble glycogen incorrectly, or when quality-control mechanisms fail, the sugar becomes poorly branched and settles into dense, insoluble clumps called polyglucosan bodies. Over time, these toxic deposits accumulate inside brain cells, causing irreversible tissue damage.
Physicists at The City College of New York have demonstrated a new way to transfer microwave signals onto light using magnetic waves inside a layered semiconductor. The work establishes a materials platform for building interfaces that could one day link quantum computers through optical networks. The research, titled “Microwave-to-optical transduction using magnon–exciton coupling,” was led by the Laboratory for Nano and Micro Photonics (LaNMP) at CCNY, headed by physics professor Vinod M. Menon. It appears in the journal Nature Materials.
Many of today’s leading quantum processors use microwave signals, while light is far better suited to carrying information over long distances through optical fiber. Linking the two requires a transducer: a device that converts a signal from one frequency range to another while preserving the information it carries.
The team turned to chromium sulfide bromide (CrSBr), a layered magnetic semiconductor. When driven by microwaves, the atomic magnetic moments in the crystal move collectively, producing waves known as magnons. These waves shift the energies of excitons, bound pairs of electrons and holes that interact strongly with light. As a result, laser light reflected from the crystal picks up a coherent optical signal that tracks the microwave drive. The approach takes advantage of the especially strong interaction between light and matter near exciton resonances.
Understanding gene regulation may be key to interpreting human disease genetics. Genes are regulated in part by stretches of DNA called enhancers, which define when, where and how strongly each gene is turned on. Mapping enhancers and how they function in specific cell types is necessary for understanding gene regulation and disease-related genetic variants. But the location and activity of enhancers are highly cell type-specific, making it difficult to accurately predict enhancer–gene interactions.
In recent years, researchers have developed several computational models to predict enhancer–gene regulatory interactions using measurements of chromatin state and three-dimensional contacts.
These models have produced enhancer–gene maps spanning hundreds of cells and tissues. However, these methods remain limited, and confirming their accuracy is difficult because the necessary experiments have been done in only a handful of cell types.
Cornell physicists have discovered that minimizing disorder, not varying electron count, is the key factor for controlling superconductivity in the unique material iron selenide (FeSe), a new insight for understanding high-temperature superconductors.
Using a new technique to control this iron-based superconductor, researchers in Kyle Shen’s lab have found that iron selenide’s superconducting “dome”—the curve tracing how superconductivity strengthens and then weakens as the properties are tuned—is more closely linked to resistance caused by imperfections in its crystal lattice than to the number of electrons flowing through the crystal. Iron selenide could be fundamentally different from other high-temperature (or unconventional) superconductors, the finding suggests.
“We found that in this material, that dome is driven by factors much different than what you see normally,” said postdoctoral researcher Paul Malinowski, a former Klarman Postdoctoral Fellow in the College of Arts and Sciences (A&S). “It’s not driven by how many electrons you’re adding in, but rather, it’s driven by the obstacles the electrons are hitting—how perfect or imperfect is the crystal lattice?”