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<jats:p>Cytotoxic T lymphocytes (CTLs) and natural killer cells kill virus-infected and tumor cells through the polarized release of perforin and granzymes. Perforin is a pore-forming toxin that creates a lesion in the plasma membrane of the target cell through which granzymes enter the cytosol and initiate apoptosis. Endosomal sorting complexes required for transport (ESCRT) proteins are involved in the repair of small membrane wounds. We found that ESCRT proteins were precisely recruited in target cells to sites of CTL engagement immediately after perforin release. Inhibition of ESCRT machinery in cancer-derived cells enhanced their susceptibility to CTL-mediated killing. Thus, repair of perforin pores by ESCRT machinery limits granzyme entry into the cytosol, potentially enabling target cells to resist cytolytic attack.</jats:p>

<jats:p>Natural molecular machines contain protein components that undergo motion relative to each other. Designing such mechanically constrained nanoscale protein architectures with internal degrees of freedom is an outstanding challenge for computational protein design. Here we explore the de novo construction of protein machinery from designed axle and rotor components with internal cyclic or dihedral symmetry. We find that the axle-rotor systems assemble in vitro and in vivo as designed. Using cryo–electron microscopy, we find that these systems populate conformationally variable relative orientations reflecting the symmetry of the coupled components and the computationally designed interface energy landscape. These mechanical systems with internal degrees of freedom are a step toward the design of genetically encodable nanomachines.</jats:p>

<jats:p>Proton ceramic reactors offer efficient extraction of hydrogen from ammonia, methane, and biogas by coupling endothermic reforming reactions with heat from electrochemical gas separation and compression. Preserving this efficiency in scale-up from cell to stack level poses challenges to the distribution of heat and gas flows and electric current throughout a robust functional design. Here, we demonstrate a 36-cell well-balanced reactor stack enabled by a new interconnect that achieves complete conversion of methane with more than 99% recovery to pressurized hydrogen, leaving a concentrated stream of carbon dioxide. Comparable cell performance was also achieved with ammonia, and the operation was confirmed at pressures exceeding 140 bars. The stacking of proton ceramic reactors into practical thermo-electrochemical devices demonstrates their potential in efficient hydrogen production.</jats:p>

<jats:p> Cells migrate through crowded microenvironments within tissues during normal development, immune response, and cancer metastasis. Although migration through pores and tracks in the extracellular matrix (ECM) has been well studied, little is known about cellular traversal into confining cell-dense tissues. We find that embryonic tissue invasion by <jats:italic>Drosophila</jats:italic> macrophages requires division of an epithelial ectodermal cell at the site of entry. Dividing ectodermal cells disassemble ECM attachment formed by integrin-mediated focal adhesions next to mesodermal cells, allowing macrophages to move their nuclei ahead and invade between two immediately adjacent tissues. Invasion efficiency depends on division frequency, but reduction of adhesion strength allows macrophage entry independently of division. This work demonstrates that tissue dynamics can regulate cellular infiltration. </jats:p>

<jats:p> Translational symmetry breaking is antagonistic to static fluidity but can be realized in superconductors, which host a quantum-mechanical coherent fluid formed by electron pairs. A peculiar example of such a state is the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, induced by a time-reversal symmetry–breaking magnetic field applied to spin-singlet superconductors. This state is intrinsically accompanied by the superconducting spin smecticity, spin density–modulated fluidity with spontaneous translational-symmetry breaking. Detection of such spin smecticity provides unambiguous evidence for the FFLO state, but its observation has been challenging. Here, we report the characteristic “double-horn” nuclear magnetic resonance spectrum in the layered superconductor Sr <jats:sub>2</jats:sub> RuO <jats:sub>4</jats:sub> near its upper critical field, indicating the spatial sinusoidal modulation of spin density that is consistent with superconducting spin smecticity. Our work reveals that Sr <jats:sub>2</jats:sub> RuO <jats:sub>4</jats:sub> provides a versatile platform for studying FFLO physics. </jats:p>

<jats:p> A scanning tunneling microscope (STM) combined with a pump-probe femtosecond terahertz (THz) laser can enable coherence measurements of single molecules. We report THz pump-probe measurements that demonstrate quantum sensing based on a hydrogen (H <jats:sub>2</jats:sub> ) molecule in the cavity created with an STM tip near a surface. Atomic-scale spatial and femtosecond temporal resolutions were obtained from this quantum coherence. The H <jats:sub>2</jats:sub> acts as a two-level system, with its coherent superposition exhibiting extreme sensitivity to the applied electric field and the underlying atomic composition of the copper nitride (Cu <jats:sub>2</jats:sub> N) monolayer islands grown on a Cu(100) surface. We acquired time-resolved images of THz rectification of H <jats:sub>2</jats:sub> over Cu <jats:sub>2</jats:sub> N islands for variable pump-probe delay times to visualize the heterogeneity of the chemical environment at sub-angstrom scale. </jats:p>

<jats:p>Interlayer excitons, electron-hole pairs bound across two monolayer van der Waals semiconductors, offer promising electrical tunability and localizability. Because such excitons display weak electron-hole overlap, most studies have examined only the lowest-energy excitons through photoluminescence. We directly measured the dielectric response of interlayer excitons, which we accessed using their static electric dipole moment. We thereby determined an intrinsic radiative lifetime of 0.40 nanoseconds for the lowest direct-gap interlayer exciton in a tungsten diselenide/molybdenum diselenide heterostructure. We found that differences in electric field and twist angle induced trends in exciton transition strengths and energies, which could be related to wave function overlap, moiré confinement, and atomic reconstruction. Through comparison with photoluminescence spectra, this study identifies a momentum-indirect emission mechanism. Characterization of the absorption is key for applications relying on light-matter interactions.</jats:p>

<jats:p> Cross-electrophile coupling (XEC) reactions of aryl and alkyl electrophiles are appealing but limited to specific substrate classes. Here, we report electroreductive XEC of previously incompatible electrophiles including tertiary alkyl bromides, aryl chlorides, and aryl/vinyl triflates. Reactions rely on the merger of an electrochemically active complex that selectively reacts with alkyl bromides through 1e <jats:sup>–</jats:sup> processes and an electrochemically inactive Ni <jats:sup>0</jats:sup> (phosphine) complex that selectively reacts with aryl electrophiles through 2e <jats:sup>–</jats:sup> processes. Accessing Ni <jats:sup>0</jats:sup> (phosphine) intermediates is critical to the strategy but is often challenging. We uncover a previously unknown pathway for electrochemically generating these key complexes at mild potentials through a choreographed series of ligand-exchange reactions. The mild methodology is applied to the alkylation of a range of substrates including natural products and pharmaceuticals. </jats:p>

<jats:p> Further enhancing the performance and stability of inverted perovskite solar cells (PSCs) is crucial for their commercialization. We report that the functionalization of multication and halide perovskite interfaces with an organometallic compound, ferrocenyl-bis-thiophene-2-carboxylate (FcTc <jats:sub>2</jats:sub> ), simultaneously enhanced the efficiency and stability of inverted PSCs. The resultant devices achieved a power conversion efficiency of 25.0% and maintained &gt;98% of their initial efficiency after continuously operating at the maximum power point for 1500 hours under simulated AM1.5 illumination. Moreover, the FcTc <jats:sub>2</jats:sub> -functionalized devices passed the international standards for mature photovoltaics (IEC61215:2016) and have exhibited high stability under the damp heat test (85°C and 85% relative humidity). </jats:p>

<jats:p>Understanding the drivers of evolution is a fundamental aim in biology. However, identifying the evolutionary impacts of human activities is challenging because of a lack of temporal data and limited knowledge of the genetic basis of most traits. Here, we identify the drivers of evolution toward maturity at an earlier age in Atlantic salmon through two types of fisheries-induced evolution acting in opposing directions: an indirect effect linked with harvest of a salmon prey species (capelin) at sea (selection against late maturation) and a direct effect due to net fishing in rivers (selection against early maturation). Because capelin are harvested as an aquaculture feed protein source, we hereby determine an indirect path by which salmon aquaculture may influence wild salmon populations.</jats:p>