Catálogo de publicaciones - revistas

<jats:title>Surfaces directing fluid flows</jats:title> <jats:p> Although surfaces can be made to attract or repel liquids using coatings, surface textures with specific curvature can also be used to achieve the same effect. However, fluid transport is usually limited by the specific pattern that only drives flow at the surface itself. Feng <jats:italic>et al</jats:italic> . created a dual-reentrant surface that has an asymmetric profile so that fluids spread out at the surface and subsurface layers. Furthermore, these surfaces can be designed so that different liquids will naturally steer in opposing directions simply because of their specific interactions with the surface. —MSL </jats:p>

<jats:title>CRISPR and Caspase meet</jats:title> <jats:p> Many prokaryotes use CRISPR RNA–bound proteins to sense viral RNA instead of DNA to set an immune response in motion that protects from virus infection. Although these ribonucleoproteins are typically composed of many protein subunits, van Beljouw <jats:italic>et al</jats:italic> . discovered that CRISPR-Cas type III-E systems are formed by a large, single-component effector protein capable of double RNA cleavage. Distinct from other systems, this effector forms a complex with a peptidase from the caspase family, raising the intriguing possibility that viral RNA activates a protease activity to prevent virus propagation by host suicide. —DJ </jats:p>

<jats:title>Memory and logic in the same device</jats:title> <jats:p> Future artificial intelligence applications and data-intensive computations require the development of neuromorphic systems beyond traditional heterogeneous device architectures. Physical separation between a peripheral signal-processing unit and a memory-operating unit is one of the main bottlenecks of heterogeneous architectures, blocking further improvements in efficient resistance matching, energy consumption, and integration compatibility. Tong <jats:italic>et al</jats:italic> . present a transistor-memory architecture based on a homogeneous tungsten selenide-on-lithium niobate device array (see the Perspective by Rao and Tao). Analog peripheral signal preprocessing and nonvolatile memory were possible within the same device structure, promising diverse neuromorphic functionalities and offering potential improvements in neuromorphic systems on-chip. —YS </jats:p>

<jats:title>Fermionic superradiance</jats:title> <jats:p> Placing an atomic gas inside an optical cavity can have profound effects, for example, inducing long-range atomic interactions through the coupling with the cavity’s photons. Such experiments have been done with bosonic atoms but realizing them with fermions has proven trickier. Zhang <jats:italic>et al</jats:italic> . placed an ultracold gas of fermionic lithium-6 atoms in a cavity pumped by a laser beam orthogonal to the cavity axis. For sufficiently strong pumping, the researchers detected a checkerboard pattern in the atoms’ momentum space corresponding to a superradiant phase transition in the cavity. The Pauli exclusion principle, which applies to fermions but not bosons, slowed down the atomic dynamics. —JS </jats:p>

<jats:title>Titanium gets some twins</jats:title> <jats:p> Introducing a network of nanotwins is known to improve the properties of face-centered cubic metal alloys. Zhao <jats:italic>et al</jats:italic> . used gentle compression in liquid nitrogen to introduce a similar network of nanotwins in hexagonal closed-packed titanium. By starting with a titanium that has little oxygen, the twin network can be more easily established. The nanotwinned network improved the yield strength by 50% and ductility by 20% at room temperature. The cryogenic properties were even better, with a yield strength of two gigapascals and a tensile ductility of 100% before failure. —BG </jats:p>

<jats:title>A boost for boosters</jats:title> <jats:p> The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern poses a potential obstacle to achieving vaccine-induced immunity. Pegu <jats:italic>et al</jats:italic> . examined how viral variants, including the B.1.351 (Beta) and B.1.617.2 (Delta) variant, affected the immune response in a small number of individuals who received the Moderna mRNA-1273 vaccine. By analyzing sera obtained 6 months after the second shot in the primary vaccine series, the researchers found that neutralizing antibody titers persisted against all variants tested. However, neutralizing antibodies against the B1.351 variant had dropped considerably by 6 months, and some individuals had weak, and in some cases no, neutralizing activity. These data may help to guide public health policies regarding additional booster vaccinations. —PNK </jats:p>

<jats:title>Barrels that build barrels</jats:title> <jats:p> Cells produce specialized machinery to produce functional β-barrel proteins that are involved in cross-membrane transport and membrane protein biogenesis in eukaryotic organelles and some bacteria. Wang <jats:italic>et al</jats:italic> . studied one of these systems that is itself a β-barrel, the mitochondrial sorting and assembly machinery (SAM), in complex with one of its client proteins, translocase of the outer membrane (TOM). TOM subunits can be added one at a time while the protein is bound to SAM. Compared with the full TOM core complex, the final TOM core subunit clashes with SAM and suggests that release of TOM may be driven by its association. —MAF </jats:p>