Browse Articles
Discover research articles across all indexed journals
Regional variability but global flux balance in the deep sulfur cycle
Sulfur is a key volatile that influences Earth’s redox state, climate, and deep geochemical cycles. Subduction zones are the primary pathways carrying sulfur from the surface into the mantle, yet the global sulfur budget and recycling efficiency remain uncertain. Here, we compile a trench-by-trench inventory of subducting sulfur using sediment compositions from ocean drilling programs collected near major trenches, integrated with spatially resolved estimates of oceanic crustal and serpentinite thicknesses derived from seismic data. Our results reveal pronounced spatial heterogeneity in sulfur fluxes, driven by large variations in sedimentary sulfur contents and fundamental tectonic differences between erosive and accretionary margins. Slab-to-arc sulfur recycling efficiency averages 37% globally but varies markedly among individual subduction systems. Despite this heterogeneity, the global sulfur cycle appears balanced on the modern Earth: Sulfur input into the mantle via slab subduction (57 ± 3 Mt y –1 ) is matched within uncertainty by mantle output (~60 ± 14 Mt y –1 ) through mid-ocean ridges, volcanic arcs, and intraplate magmatism. This balance suggests that Earth’s deep sulfur cycle operates in a steady state today. Sulfur isotopes reveal a systematic decoupling, with subducted sulfur carrying negative δ 34 S values, whereas arc sulfur output is consistently positive. The strong spatial variability in sulfur inputs and recycling efficiency underscores the individuality of Earth’s subduction zones, but the balanced input–output fluxes highlight its capacity for self-regulation. These findings have important implications for atmospheric chemistry, surface environments, and the long-term evolution of the deep Earth’s sulfur cycle.
Correction: Impacts of land use on soil carbon, nitrogen, and phosphorus in the Eastern Qilian Mountains
Glycolipids slow interfacial proton migration while preserving surface proton retention
Proton gradients power diverse biological processes, yet how interfacial proton migration is regulated remains unclear. Here we quantify how membrane composition controls interfacial proton migration using an approach that releases protons directly at the surface of a membrane patch via an embedded ionophore. Fluorometrically monitoring proton arrival at a distant patch across neutral, negatively charged, and positively charged membranes, we confirm that both the lateral surface diffusion coefficient and the activation barrier for proton release into the bulk vary rather modestly. In contrast to membrane electrostatics, membrane incorporation of glycolipids typical of thylakoid membranes—digalactosyldiacylglycerol and sulfoquinovosyldiacylglycerol—leads to a more pronounced reduction of the lateral proton diffusion coefficient, with comparatively small effects on the surface-to-bulk release barrier. Thus, interfacial proton migration is governed primarily by hydration-layer properties rather than membrane charge. These results establish membrane-anchored sugars as potent modulators of long-range proton conduction and provide a mechanistic framework for localized proton coupling in glycolipid-rich biological membranes.
Circulating PEG-indoleamine 2,3-dioxygenase ameliorates diverse inflammatory diseases without toxicity or compromising immunocompetence
Indoleamine 2,3-dioxygenase (IDO), the enzyme responsible for tryptophan catabolism, is protective in many autoimmune and inflammatory diseases. We previously developed a localized immunomodulation approach through the fusion of IDO to a carbohydrate binding protein [E. Bracho-Sanchez et al. , Nat. Biomed. Eng. 7 , 1156–1169 (2023)]. Here we further develop IDO as a protein therapeutic for inflammation, investigating systemic delivery via conjugation of poly(ethylene glycol) (PEG) to IDO. PEGylation extended circulation time and treatment PEG-IDO demonstrated therapeutic efficacy in five autoimmune and inflammatory models. Treatment with a single dose of PEG-IDO resulted in reversal of hind limb paralysis in experimental autoimmune encephalomyelitis as model of multiple sclerosis; protected against hepatic damage in liver ischemia-reperfusion injury; prevention of abdominal aortic aneurysm; and decreased severity of imiquimod-induced psoriasis. Treatment with two doses of PEG-IDO provided maintenance of body weight and colon length in acute ulcerative colitis. PEG-IDO treatment increased regulatory T cell populations and reduced pathogenic Th17 cell populations and inflammatory cytokine production. Systemic delivery of PEG-IDO had little-to-no off-target effects. Mice maintained immunocompetency, clearing the Listeria monocytogenes infection, and had no observed toxicity. Additionally, PEG-IDO increased serum kynurenine, consistent with a kynurenine-mediated mechanism of action. These findings demonstrate systemic immunomodulation via circulating PEG-IDO ameliorates a breadth of disparate autoinflammatory diseases, protecting against inflammation-driven tissue destruction in spinal cord, liver, abdominal aorta, skin, and colon, while presenting a positive safety profile, and expanding the scope of potential applications for this therapeutic approach.
Per os infectivity factors are essential for bracovirus infection and wasp parasitism
Many parasitoid wasps in the family Braconidae rely on bracoviruses to parasitize lepidopteran hosts. Bracoviruses evolved from a virus in the family Nudiviridae , while nudiviruses are closely related to baculoviruses. A per os infectivity factor (PIF) complex is essential for oral infection of hosts by baculoviruses. Bracoviruses encode 8 PIF homologs but have no per os infection route because wasps inject virions into hosts. Thus, the mechanism underlying how bracoviruses enter lepidopteran host cells is unknown. Here we used the parasitoid Microplitis mediator , its lepidopteran hosts Mythimna separata and Helicoverpa armigera , and M. mediator bracovirus (MmBV) to elucidate the function of bracoviral PIFs. We identified a ~720-kDa PIF complex on the envelope of MmBV virions. In addition to PIF0-4, PIF6, and PIF8, we identified two other proteins in the MmBV PIF complex: PIF5-3 and a wasp encoded β-propeller domain-containing protein named P52. The other two PIF5 paralogs (PIF5-1 and PIF5-2) were not associated with the PIF complex. Knocking down any component in the PIF complex resulted in degradation, which suggested all components are essential for stability. Using expression of an MmBV ankyrin gene as a marker, we determined that MmBV PIFs are essential for systemic infection of host larvae. Knocking down any PIF complex component or double silencing of PIF5-1 and PIF5-2 also resulted in failed parasitism as measured by no survival of M. mediator offspring. Altogether, our results demonstrate an essential role for the MmBV PIFs in systemic infection of a lepidopteran host.
Origins of stomatal mechanics in grasses
Inhibition of elastin degradation alleviates joint degeneration in aging mice, dogs, and human models
Extracellular matrix degradation is a fundamental pathological feature of osteoarthritis, while the roles of degraded matrix remain largely unknown. We previously showed that serum elastin fragments were a systemic aging driver. Here, we found that elastin fragments were upregulated in synovial fluid in dual-center osteoarthritis patients. Elastin fragments actively impaired joint tissue in mice and human explants. Mechanistically, a specific elastin motif containing Valine-Glycine-Valine-Alanine-Proline-Glycine (VGVAPG) oligopeptide (E-motif) promoted macrophage secretion of inflammatory factors via the neuraminidase-1, a component of the elastin receptor complex. These inflammatory factors, together with the E-motif, upregulated serum amyloid A3 protein in chondrocytes, accelerating cartilage degeneration. Therapeutically, both the myeloid-specific knockout of neutrophil elastase and the pharmacological inhibition using a clinically applied drug (sivelestat) alleviated joint degeneration in naturally aging mice partly by reducing elastin fragments levels. The pharmacological inhibitor exhibited 1-y systemic safety in dogs and alleviated osteoarthritis-like phenotypes in naturally aging dogs and human explants. Finally, several matrix fragments, including the fragments of type II collagen, fibronectin, hyaluronic acid, and aggrecan, were demonstrated to universally induce cartilage degeneration. Conclusively, this study identifies degraded matrix, especially elastin fragments, as one of the drivers of joint degeneration via pathological macrophage–chondrocyte crosstalk, suggesting elastase inhibitors as a potential therapeutic strategy for aging-related osteoarthritis.
Living growth of ultra-bright 2D perovskites with long-lived carriers
Abstract Growth-induced defects and strain in two-dimensional (2D) perovskites severely limit carrier transport and suppress radiative efficiency, thereby sacrificing the carrier lifetime and obscuring the advantages from quantum confinement. Here, we report a near-equilibrium isothermal (NEIT) growth paradigm of 2D perovskite single crystals that exhibits living growth characteristics analogous to living polymerization. This approach confines crystallization primarily to initial nuclei, resulting in ultra-low nucleation density and yielding centimeter-scale single crystals of PEA 2 PbI 4 (Pb-n1), PEA 2 MAPb 2 I 7 (Pb-n2), and PEA 2 MA 2 Pb 3 I 10 (Pb-n3) with enhanced crystallographic perfection. This process achieves ~89% utilization of Pb precursor for Pb-n1, significantly surpassing ~13% from conventional methods and aligning with green-chemistry and sustainable synthetic principles. Additionally, the trap density gets suppressed by one order of magnitude. This unlocks high photoluminescence quantum yields (PLQYs, 77 ± 2% for Pb-n1), first cavity-free lasing in 2D Pb-n1 perovskite flakes, and long carrier lifetimes with diffusion lengths up to ~1.92 μm rivaling 3D perovskites. Critically, the living NEIT growth successfully enables the epitaxy of 2D bulk perovskite heterostructures, driving 60-fold accelerated photocarrier separation in lateral photodetectors. This near-equilibrium living growth paradigm establishes defect-minimized 2D perovskites as a versatile and active platform for high-performance quantum-well optoelectronics.
Mesoscale developmental rivalry in the human extrastriate visual cortex
The human extrastriate visual cortex contains fine-scale columns selectively responsive to motion, disparity, and color. However, the developmental interplay between these functional modules remains poorly understood. Using high-resolution functional MRI, we compared the mesoscale organization of the extrastriate cortex in 16 individuals with normal vision and 15 participants with amblyopia (PwA) caused by strabismus (n = 8) or anisometropia (n = 7). In controls, the cortical territory occupied by disparity-selective columns exhibited a competitive relationship with that of motion- and color-selective columns. In PwA, we witnessed a reduction in the size of disparity-selective columns accompanied by expansion of the cortical territory allocated to motion- and color-selective columns, while the interdigitated organization of these sites remained unchanged. At the macroscale, this phenomenon simply manifested as weaker disparity- plus stronger motion- and color-selective responses in PwA than controls. Our results show that the mesoscale modules are rivals in development allowing intact functions to usurp those that are compromised.
Verifier-initiated quantum message-authentication via quantum zero-knowledge proofs
Opportunity and risk in achieving food production and conservation goals at high altitude: Evidence from the Tibetan Plateau
The Tibetan Plateau, the Earth’s highest and largest plateau, has a harsh environment for agriculture, and is a global biodiversity hotspot, raising the challenge of simultaneously satisfying food production and conservation goals. Currently, agriculture involves crop production on steep slopes and overgrazing, which threatens future productivity. The Tibetan Plateau is also undergoing climate change. We evaluate food production from 1990 to 2020 and use these results to model future trends and risks to food production on the Tibetan Plateau. We assess the feasibility of achieving both food production and conservation goals simultaneously under climate change scenarios. Food production increased 32.33% over three decades, providing 2,892.98 kcal d −1 cap −1 , more than enough to satisfy food self-sufficiency. Under climate change, the Tibetan Plateau will become warmer and wetter under Shared Socioeconomic Pathways (SSPs) SSP126, SSP245, and SSP585, which combined with agricultural advances (e.g., improved mechanization and irrigation), will likely result in increased yields even with a 10% reduction in cropland area—greater than the total area of all steeply sloping cropland, thereby allowing retirement of steeply sloping cropland and livestock reductions while still meeting food production goals. Meanwhile, key ecosystem services, including carbon sequestration, water retention, and habitat quality, are also projected to improve substantially. Nonetheless, the increasing frequency and severity of extreme weather events are expected to reduce food production, undermine current dietary requirements and may threaten the minimum nutritional intake required for humans.
Thermomechanically squeezed multi-mode phonon lasers with levitated optomechanics
Chaos-generating periodic orbits of topological defects in confined active nematics
Active nematics in two dimensions stir themselves efficiently through internally generated chaotic flows, largely driven by motile + 1 / 2 disclinations.We investigate how this tendency toward chaotic fluid stirring can, counterintuitively, produce certain ordered, periodic flows in confinement, characterized by stable periodic orbits of + 1 / 2 disclinations. We computationally study two-dimensional active nematics in systems with boundary conditions requiring a prescribed number n of excess + 1 / 2 disclinations, using Beris-Edwards nematohydrodynamics simulations alongside an agent-based simulation approach. We find that when confinement is sufficiently strong to prevent defect pair-nucleation, but not strong enough to arrest all flow, then n = 3 defects generically follow a “golden braid” orbit as observed recently in experiments, and we predict a “silver braid” orbit of n = 4 defects. For these results and for greater numbers of defects, we show that the periodic or chaotic nature of the dynamics is determined by a balance between the number of defects and the number of vortices in the flow field, suggesting a design criterion for ordered flows in active nematics.
Author Correction: The rhythmic coupling of Egr-1 and Cidea regulates age-related metabolic dysfunction in the liver of male mice
Louis E. Brus (1943–2026): A consummate physical chemist and a pioneer in the exploration of spectroscopy of materials at the nanoscale
Last year we lost a true pioneer in the field of nanoscience. Louis E. Brus didn’t chase fame, he chased “the problem.” His career is a monument to the power of curiosity driven science, the kind of impactful science nurtured by Bell Laboratories in the 1980s and 1990s. Collaborative to his core, Louis is as good an example of a “Bell Labs type” as you can find. His intellect, mentorship, and kindness will be greatly missed by his friends, students, and colleagues.
Annexing isothermal nucleotide amplification enables probe-guided amplification and direct detection at ambient temperature
Abstract Isothermal nucleic acid amplification offers advantages over qPCR for decentralized diagnostics but remains constrained by rigid primer design, detection complexity, and equipment dependence. Recombinase-based systems operate at lower temperatures than other isothermal methods but require long primers and auxiliary enzymatic processing for detection. Here we introduce Annexing Isothermal Nucleotide Amplification (ANINA), a probe-guided recombinase-based framework integrating amplification and detection at ambient temperatures within a single lyophilized reaction. An Annexing Probe recruits short primers through spatial annexation, enabling efficient amplification at 25 °C within 30 minutes and direct lateral flow detection without auxiliary enzymatic processing. We show this framework detects attomolar WSSV and EBV DNA in abundant host gDNA, supports target-specific detection of DNA and RNA viruses and bacteria in contrived matrices, enables quantitative real-time detection comparable to qPCR, and facilitates a fully equipment-free 45-minute sample-to-answer workflow that detects early viral infection in a natural host model with qPCR-level sensitivity and improved performance over a commercial antigen test.
Liquid–liquid phase separation enables chromatography-free purification and high-performance spidroin-amyloid hybrid silk fibers
Large-scale production of artificial spider silk fibers requires heterologous expression of spider silk proteins (spidroins), yet current methods remain limited by low yields and costly purification processes. To overcome these challenges, we engineered mini-spidroins in which the poly-alanine motifs of the repetitive region were replaced with the non-natural amyloidogenic β16 peptide, significantly enhancing expression yields and solubility. Furthermore, we developed a simple, chromatography-free purification method for these constructs based on NaCl-induced liquid–liquid phase separation (LLPS). This one-step purification strategy reduced processing costs by up to 99% compared to conventional affinity chromatography while achieving yields of ~300 mg of purified protein per liter of shake flask culture and ~25 g L −1 from bioreactor cultivations. The purified engineered mini-spidroins could be spun into continuous fibers using an all-aqueous, biomimetic spinning process triggered by a pH drop. The resulting fibers exhibited mechanical properties comparable to those produced from the mini-spidroin NT2RepCT, which requires conventional chromatographic purification. Together, our protein-engineering approach and LLPS-based purification method provide a potentially scalable, sustainable, and cost-effective platform for artificial spider silk, representing a major step toward the commercial viability of recombinant silk-based materials.
Catalyst-controlled site-selective dehydrogenation, a stepping stone for C–H oxidations in complex terpenes synthesis
mRNA lipid nanoparticle cancer vaccine platform delivering multiple STING activators for enhanced antitumor activity
mRNA-based cancer vaccines offer a modular and safe platform to elicit antitumor immunity, yet their efficacy is often limited by inefficient mRNA delivery and inadequate dendritic cell (DC) activation, both of which are essential for initiating robust cytotoxic T cell responses. Inadequate innate immune activation coupled with poor antigen presentation further diminishes their effectiveness, particularly in immunologically “cold” tumors. While stimulator of interferon genes (STING) agonists can enhance DC maturation and cross-presentation, their therapeutic utility is constrained by poor intracellular delivery and limited colocalization with tumor antigens. In this study, we developed a lipid nanoparticle (LNP) platform via high-throughput screening of ionizable lipids for potent mRNA delivery to DCs both in vitro and in vivo. To amplify immune activation, we coencapsulated the STING agonists c-di-AMP (AMP) and manganese (Mn 2+ ) together with tumor antigen-encoding mRNA into the lead LNP formulation. This codelivery strategy synergistically activated type I interferon signaling, upregulated costimulatory molecules, enhanced antigen presentation, and elicited potent tumor-specific T cell responses and superior antitumor efficacy. Our results demonstrate that integrating innate immune stimulation with mRNA-LNP delivery provides a promising strategy to overcome current limitations in mRNA vaccine efficacy and to improve cancer immunotherapy outcomes.