Yumei Wang

The basal streptophyte Mesostigma viride represents a critical evolutionary transition toward land plants, yet the molecular basis of its ancestral light-harvesting strategy remains elusive. Here, we present a 2.25-angstrom resolution cryo-EM structure of the M. viride PSII-LHCII-LHCP supercomplex, revealing a unique C ₂ S ₂ M _p2 L _p2 -type architecture. Our structure reveals a nearly complete set of conserved PSII core subunits, indicating that much of the PSII structural framework found in terrestrial plants was established early in the streptophyte lineage. At the periphery, the complex features a specialized antenna module in which two ancestral LHCP monomers flank CP29. These ancestral antenna proteins bind an unusually high number of carotenoids, with seven carotenoids per subunit, and extensively incorporate marine-type keto carotenoids, siphonaxanthin, and siphonein, throughout the complex, thereby broadening absorption in the blue-green region. The canonical LHCII trimer exhibits a distinctive chlorophyll b macrocluster and a 96-femtosecond ultrafast energy transfer component. Together, these findings provide a high-resolution molecular framework for an evolutionary intermediate that combines high-capacity aquatic light harvesting with structural features potentially relevant to photoprotection during the transition toward terrestrial life.

P-type ZrCoSb-based half-Heusler compounds are promising thermoelectric materials for high-temperature power generation because of their excellent thermal stability and mechanical robustness. However, their performance still lags behind that of state-of-the-art p-type ZrCoBi systems, mainly due to the limited doping efficiency of conventional aliovalent doping strategies, which hinders the realization of highly degenerate carrier transport and consequently restricts power factor optimization. This study highlights the pivotal role of phase diagram engineering in maximizing the thermoelectric performance of ZrCoSb-based half-Heusler materials. Through precisely tuning the Co content guided by experimental phase diagrams, simultaneous enhancement of electronic transport properties and suppression of lattice thermal conductivity have been realized. Under Co-deficient conditions, the Sn doping efficiency approaches 100%, increasing the hole concentration to 3.8 × 1021 cm–3 and activating the secondary Γ valence-band valley in addition to the primary L valleys. The resulting multivalley transport increases the effective valley degeneracy from 8 to 10 and yields a peak power factor of 40.4 μW cm–1 K–2 and an average power factor of 37.6 μW cm–1 K–2 over 300–973 K, representing the high reported value to date among p-type ZrCoSb-based half-Heuslers. The synergistic effect of Co vacancy engineering and Hf alloying suppresses thermal transport, culminating in a peak zT of 1.2 at 973 K. Finally, a single-stage thermoelectric module was fabricated using the optimized material, demonstrating a conversion efficiency of ∼11% at a temperature difference of 673 K, overperforming all previously reported ZrCoSb-based single-stage thermoelectric devices. This work establishes phase diagram engineering as a powerful and universal strategy for developing high-performance thermoelectric materials and devices.

Euglena gracilis is a phototrophic flagellate that has evolved through secondary endosymbiotic events and belongs to green-lineage organisms. We report a unique structure of photosystem I-light harvesting complex I (PSI-LHCI) supercomplex from E. gracilis at a 2.23-angstrom resolution by cryo–electron microscopy. The supercomplex is composed of 8 core subunits and 16 LHCIs and exhibits distinctive structural features compared to its counterparts in green algae and plants. The LHCI subunits encircle the core complex, forming a two-layered arrangement that comprises six pairs of tightly packed heterodimers. Specifically, the 16 LHCIs consist of 4 diadinoxanthin-chlorophyll (Chl) a/b–binding antennae (Lhcbm) and 12 diadinoxanthin-Chl a–binding antennae (Lhca), and they exhibit characteristic pigment compositions combining features of green- and red-lineage organisms. These findings provide a robust structural foundation for elucidating the mechanisms of light harvesting and energy transfer as well as insights into the evolutionary changes of green-lineage PSI-LHCI.

To overcome the limitations of traditional single-crystal X-ray diffraction (SCXRD) for microcrystalline materials and the peak-overlapping issue of powder Xray diffraction (PXRD), this study employed cryogenic continuous rotation electron diffraction (cryo-cRED) with a low-dose strategy to determine the crystal structure of CL30, a novel silicogermanate framework. It is confirmed that CL30 crystallizes in the C 2/ m space group and has layered topology composed of discontinuous zigzag chains connected by double four-membered ring (d4r) units, with fluoride anions (F ^- ) occluded in the d4r units. In CL30, charge balance involves organic structure-directing agent (OSDA) cations, occluded F ^- , and terminal oxygen sites whose protonation state cannot be established from the present 3D ED data. F ^- encapsulated in the d4r units contributes to charge compensation as the counter-anion to OSDA cations, rather than only balancing the framework charge. Although the refinement indices ( R ₁ = 0.29, wR ₂ = 0.71) exceed typical small‑molecule crystallography standards, the structural model remains highly reliable, as supported by geometric restraints and validation. In electron diffraction, elevated R ₁ values are commonly attributed to intrinsic factors of the technique, such as dynamic scattering, detector noise from scintillator‑based detectors, and TEM stage instability (large sphere of confusion). This work not only introduces a new structural prototype to the silicogermanate family but also establishes a feasible workflow for determining structures of radiation-sensitive microcrystalline porous materials.

Despite their promise as lightweight, ultralow–thermal-conductivity thermoelectric (TE) materials, aerogels have been largely limited to p-type organic or carbon-based systems with modest zT < 0.1 at 300 kelvin. Here, we propose a stepwise synthesis strategy that yields the first inorganic aerogel exhibiting state-of-the-art n-type TE performance. Optimized aerogels with 95% porosity exhibit a high power factor of 34.8 microwatts per meter per square kelvin and an ultralow thermal conductivity of 0.061 microwatts per meter per kelvin, resulting in zT values of 0.17 at 300 kelvin and 0.24 at 383 kelvin. A vertical TE generator prototype with six TE-aerogel legs achieves a gravimetric output power of 76 microwatts per gram under a Δ T of ~60 kelvin. To address brittleness, a polyimide-encapsulated aerogel with bioinspired architecture was developed, achieving a high compressive strength to 1.4 kilopascals while maintaining excellent TE performance. This work establishes a generalizable method for designing high-performance flexible inorganic aerogels, opening more possibilities for lightweight wearable energy harvesting technologies.

The decoupling mechanism of electrical conductivity and Seebeck coefficient in 9-4-9-type Ca _{9− y} Eu _y Zn _4.7 Sb ₉ was uncovered.

Half-Heusler compounds are promising thermoelectric materials for high-temperature applications, yet their performance is limited by high lattice thermal conductivity. Here, we present an alternative approach to synthesize ZrNiSn-based half-Heusler compounds with hierarchical architectures across multiple length scales. By utilizing short-duration mechanical alloying to produce nonequilibrium precursors, followed by reactive sintering, we enable precise control over phase composition and microstructural features. This approach results in multi-scale architectures comprising interstitial defects, grain boundaries, nanoprecipitates, and pores, enabling strong phonon scattering. The optimized Zr_0.75Hf_0.25NiSn_0.99Sb_0.01 alloy exhibits a lattice thermal conductivity as low as 1.9 W m⁻¹ K⁻¹ and a high power factor of 50 µW cm⁻¹ K⁻², yielding an impressive dimensionless figure of merit (zT) of 1.33 at 873 K. This performance surpasses that of ZrNiSn-based compounds synthesized via conventional methods such as arc melting and solid-state reaction. Our method, distinguished from conventional melting synthesis approaches through its simplicity, cost-effectiveness, and scalability, provides a versatile framework for achieving efficient hierarchical phonon scattering while preserving high carrier mobility in half-Heusler compounds and highlights the potential of reactive sintering for advancing thermoelectric materials.

The Schlafen (SLFN) genes are induced by interferons, underscoring their roles in the immune response and viral replication inhibition. SLFN14, a member of SLFN family, is associated with multiple human diseases; however, neither its functions nor its disease mechanisms are fully understood. Herein, human SLFN14 biochemically is characterized, demonstrating that it specifically cleaves RNAs containing short duplex regions, such as hairpin RNAs and tRNAs, but does not have ATPase or helicase activity. Cryogenic electron microscopy structures of SLFN14 apoenzyme (2.84 Å) and SLFN14‐hairpin RNA complex (2.88 Å) are determined, revealing that SLFN14 assembles into a ring‐like dimer and dimerization is mainly mediated by hydrophobic contacts. Two N‐terminal RNase domains of SLFN14 are organized head‐to‐tail, forming an RNA‐binding groove that can accommodate a 12‐bp hairpin RNA. The hairpin RNA is recognized mainly through phosphate backbone interactions. Further, SLFN14 is shown to inhibits HIV‐1 pseudovirus replication. The anti‐HIV‐1 activity of SLFN14 is via codon‐usage‐dependent translational inhibition and impairment of the programmed ‐1 ribosomal frameshifting, with an efficiency comparable to that of Shiftless. Using tRNA PCR arrays, SLFN14 and SLFN11 are found to decrease both nuclear‐encoded and mitochondrial tRNAs in cells. Together, these results provide novel insights into the function of SLFN14 and its role in HIV‐1 restriction.