Physics

Understanding the atomic evolution from cluster to nanocrystal has long been a challenge in nanoscience. Here, an accurate machine learning potential (MLP) of elemental Pd was developed. The large-scale capacity of this MLP affords long-time simulated annealing for a cross-scale study of Pd${}_{n}$ nanostructures ($n$=12 - 21856), revealing a continuous transition from discrete clusters to bulk-like nanocrystals and the critical size at which the transition occurs. This study paves the way for studies on other clusters.

Using molecular dynamics simulations, we show that a widely-accepted theoretical prediction for glassy-polymeric strain hardening moduli ($G_R \propto ρ_e$, where $ρ_e$ is the entanglement density) fails badly for semiflexible polymers with $N_e \lesssim 4C_\infty$. By postulating that the length, energy and strain scales controlling $G_R$ are the Kuhn length $\ell_K$ and statistical segment length $b = \sqrt{\ell_0 \ell_K}$ (where $\ell_0$ is the backbone bond length), the intermonomer binding energy $u_0$, and the incremental elastic strain $S_{\rm c}$ required to activate Kuhn-segment-scale plastic rearrangements, we develop a scaling theory predicting that $G_R = S_{\rm c}(u_0/\ell_0^3) b^3$ in the athermal limit. This prediction agrees quantitatively (semi-quantitatively) with simulated $G_R$ values for both flexible and semiflexible polymer glasses subjected to athermal uniaxial-stress extension (constant-volume simple shear), over a range of $\ell_K/\ell_0$ that is wider than that spanned by real systems.

Metabolic reprogramming is a hallmark of cancer, while tricarboxylic acid cycle is increasingly recognized as a multifaceted hub driving tumor metabolism and progression. Integrated analysis of solute carrier (SLC) transporters revealed consistent down-regulation of SLC13A2 in hepatocellular carcinoma (HCC) cells and liver tissues from human patients and mouse models. Adeno-associated virus-mediated liver-specific knockout or overexpression of SLC13A2 (SLC13A2-OE) promoted or ameliorated HCC progression, indicating its protective role. SLC13A2 inhibited HCC proliferation by decreasing mitochondrial function via suppressed glycolysis, respiration, and adenosine 5'-triphosphate production. Flux analysis showed that SLC13A2 imported citrate to generate acetyl-coenzyme A for pyruvate kinase isozyme type M2 acetylation, triggering its degradation. Reduced pyruvate kinase activity limited pyruvate supply, impairing amino acid synthesis and nucleotide metabolism. Moreover, SLC13A2-imported citrate induced intracellular protein acetylation, particularly histone proteins, which provided an epigenetic basis for transcriptional regulation and contributed to tumor suppression. Thus, SLC13A2 perturbs metabolic and transcriptional programs to suppress tumor growth, highlighting potential drug targets for HCC therapy.

Emerging static aqueous Zn─Br batteries offer substantial cost and energy density advantages but suffer from toxic Br₂ formation and polybromide shuttling. Here, we report a universal electrode engineering for advanced Zn─Br battery via incorporating layered materials into the cathode, reshaping the working mechanism from conversion to intercalation-conversion. Findings confirm that Br^- intercalate-converts to Br^-0.14 within unsaturated N-rich g-C₃N₄, effectively avoiding liquid Br₂ formation and suppressing its toxicity and diffusion. Consequently, the self-discharge of cell remarkably decreases from 96.5 to 9.5% following 12 hours resting. Through controlling 48.7% Zn depth-of-discharge and industrial-level mass loading 40 mg_(KBr) cm^-2, the multilevel pouch cell with ampere hour-level capacity exhibits 750 cycles, outperforming aqueous counterparts at high mass loadings. This electrode engineering is applicable to other layered materials, underscoring its practical universality. These findings not only unlock the full potential of aqueous Zn─Br batteries but also enrich the chemistry landscape of aqueous battery family.

To clarify the process of faulting triggered by the olivine-ringwoodite transition in deep subducted slabs, we conducted deformation experiments on mantle olivine at pressures of 15 to 20 gigapascals and temperatures of 870 to 1320 kelvins. Throughgoing faulting occurred as a result of shear localization to "soft" gouge layers, which mainly consist of kinked olivine grains. Kinking of olivine grains on the [010](100) slip system resulted in a pseudo-martensitic transition of olivine to ringwoodite via poirierite having relationships of [010]_Ol // [010]_Poi and [100]_Ol // [101]_Poi. The release of a high amount of latent heat via the poirierite-ringwoodite transition can induce a significant weakening of the fault gouge, without the aid of grain size-sensitive creep, resulting in the occurrence of faulting. The observed pseudo-martensitic transition of olivine to ringwoodite, which can proceed even at room temperature under stress, explains the cause of high seismicity in bending regions of cold subducted slabs that consist of metastable olivine.

Despite the common perception, most fatal landslides occur in human-transformed environments. Even on steep terrain, anthropogenic disturbances may fundamentally modulate landslides. Most of our knowledge regarding landslide-human interaction is restricted to local models or regional heuristic assessments based on empirical evidence. In this study, we used land-use-land-cover change as a metric to explain human pressure as a preconditioning factor for fatal landslide occurrences to provide a global overview. We addressed countries' income levels, populations, exposure, and a dataset of ≈60 years of land-use-land-cover changes with mountainous landmasses to compare landslides and fatalities across 46 countries. Our statistical analyses show that land-use-land-cover changes have a substantially greater influence on the density of fatal landslides and landslide fatalities than physical factors such as topography and precipitation, especially in lower-income countries. We observed a marginal landslide impact when the land-use-land-cover change was low, regardless of the income class. Our results emphasize that effective land-use-land-cover planning is critical to decreasing landslide fatalities, especially in low- and lower-middle-income countries.

Artificial muscles have been in development for decades and play a crucial role in the field of wearable robotics. However, a universal device for both sensing and regulating forces in artificial muscles is still absent, rendering scenario-required force control unfeasible. Inspired by Golgi tendon organs, this work proposes bionic ExoTendon for force sensing and regulating in artificial muscles as a general solution. Leveraging the principles of triboelectrification and electrostatic induction, the ExoTendon offers high linearity, minimal hysteresis, and adjustable sensitivity and range, making it suitable as the tendon of artificial muscles. Specifically, the ExoTendon effectively enable adjustment to the pretension of the artificial muscles, yielding various assistive forces under the same input. With the optimized pretension level and closed-loop force control, the artificial muscle-based exosuit achieves self-force regulation, substantially improving walking balance and speed in stroke subjects under low input, demonstrating its promise in wearable robotics and rehabilitation medicine.

Here, a donor-acceptor integrated polymer, PQIC, featuring a rigid π-conjugated framework, is reported, in which a Y-type small-molecule acceptor is covalently fused into a polymer donor backbone. PQIC exhibits balanced bipolar charge transport, reduced defect density, and high electroluminescence efficiency. When incorporated as a third component, it facilitates charge percolation, concurrently weakens electron-phonon coupling and lowers defect-state density, thereby alleviating recombination losses. As a result, PQIC-based ternary organic solar cells achieve a power conversion efficiency of 20.81% (third-party certified at 20.60%). In addition to high efficiency, the devices exhibit excellent stability, thick-film tolerance, and scalability, retaining ~85% of their initial efficiency after 2000 hours of maximum power point tracking, delivering 19.11% with a 300-nanometer-thick active layer, and reaching 19.78% for 1-square centimeter devices. These results highlight the potential of PQIC-based ternary systems for advancing organic solar cells.

Insecticide-treated nets (ITNs) are crucial for malaria control, but their efficacy is compromised by rising mosquito resistance. To better understand ITN effectiveness, we present a multidisciplinary framework through a case study examining the removal of per- and polyfluoroalkyl substances (PFAS) from ITN coatings and its impact on malaria vectors in East and West Africa. Our results show that PFAS-free pyrethroid nets exhibit reduced bio-efficacy against resistant malaria vectors compared with PFAS-based nets, despite both meeting deltamethrin specifications. Surface characterization reveals that PFAS stabilizes smaller, noncrystalline deltamethrin particulates enhancing bioavailability, while PFAS-free coatings promote particulate aggregation with an increased population of crystalline deltamethrin. Behavioral assays suggest that PFAS-free formulations reduce mosquito contact time and insecticide uptake, with resistant strains showing decreased irritancy and knockdown. These findings highlight the trade-offs of PFAS removal and stress the need for a multidisciplinary approach combining advanced chemical analytics and behavioral assessments to optimize ITNs for effective malaria control while considering environmental sustainability.

Despite numerous model-based analyses indicating a notable decline in the Atlantic Meridional Overturning Circulation (AMOC) in recent decades, robust, long-term evidence from multilatitudinal in situ observations remains limited. This study uses observational data from four mooring arrays, positioned along the western boundary of the North Atlantic (from 16.5°N to 42.5°N), to examine trends in the deep western overturning transports, derived from the cross-slope gradient in ocean bottom pressure or its equivalent, below and relative to 1000 meters that are linked to changing conditions at the western boundary. We identify a meridionally consistent decline in deep western overturning transport across these latitudes over the past two decades. This decline, observed at the western boundary, may serve as an effective indicator of AMOC weakening, despite the partial compensatory effect of overturn strengthening at the eastern boundary.

Immune checkpoint inhibitors (ICIs) can essentially treat cancer but only in a small subset of patients. Treatment strategies capable of effectively and robustly sensitizing refractory patients to ICIs represent a highly coveted yet unmet clinical need. In this study, we identified DJ-1 as a negative T cell regulator. DJ-1 knockout boosts antitumor immunity and significantly potentiates PD-1 and TIM-3 blockades in murine cancer models. Single-cell sequencing of tumor-infiltrating CD45⁺ cells revealed that DJ-1 deficiency indirectly activates T cells by reprogramming macrophages. Mechanistically, loss of DJ-1 increases reactive oxygen species (ROS) in macrophages, activating NF-κB/STAT3 signaling to promote differentiation into Cxcl9⁺ immune-stimulatory phenotypes while reducing immune-suppressive Spp1⁺ macrophages. Notably, this reprogramming may be stable across tumor microenvironments because the transplanted DJ-1-deficient macrophages maintain T cell-activating capacity. Pharmacological inhibition of DJ-1 by disulfiram markedly potentiated antitumor efficacy of PD-1 blockade. This designates DJ-1 as a promising target for overcoming immune checkpoint resistance and optimize combination therapies.

Wastewater treatment is an increasingly important yet poorly quantified source of anthropogenic methane (CH₄). Here we report facility-level emissions based on atmospheric measurements from 105 wastewater treatment plants (WWTPs) across five climatic-economic regions in China-the largest dataset to date. We found that emission factors are primarily driven by organic load and concentration. Using updated facility-level emission factors, our analysis shows that emissions from Chinese WWTP, driven by rising organic loads, grew by 12% per year since 2003, reaching 254 ± 26 Gg CH₄ year^-1 in 2023. However, the rapid expansion of WWTPs lowered the average emission factor for the urban domestic wastewater sector, limiting total emissions growth to 32% over the same period. Scenario modeling suggests that, under current technology, emissions will peak around 2040. Deploying low-emission configurations and CH₄ recovery technologies could advance the peak by 15 years and reduce 2040 emissions by 23%. Incorporating such measures into China's decarbonization strategy will be essential for achieving climate mitigation goals.

Peripheral nerve injuries (PNIs) remain a major clinical challenge, often leaving patients with lifelong sensory, motor, and functional impairments despite surgical repair. While gene and cell therapies hold promise, their translation has been hampered by the lack of safe, efficient, and targeted delivery strategies. Here, we introduce vasculogenic tissue nanotransfection (TNT) as a nonviral, reprogramming-based therapeutic platform to enhance nerve regeneration to augment surgical reconstruction. This one-time, millisecond-scale intervention reprograms resident cells in situ toward a vasculogenic phenotype, fostering neovascularization and vascular remodeling to support axonal regeneration. Through integrated in vitro screening and in vivo validation, we identified an optimized formulation of vasculogenic genes (<i>Etv2</i>, <i>Fli1</i>, and <i>Foxc2</i>; <i>EFF</i>) that maximized reprogramming efficiency and regenerative potential. In a long-segment nerve defect model reconstructed with isografts, TNT-mediated delivery of <i>EFF</i> markedly improved functional recovery, including grip strength and muscle contractility, accompanied by increased vascular density and myelinated axon counts. Together, these findings establish TNT-mediated vasculogenic reprogramming as a transformative adjunct to surgical repair of PNIs, offering a clinically translatable strategy to accelerate nerve regeneration and restore function.

The Moon has preserved a unique record of organic matter delivered and reworked by asteroid and comet impacts. Here, we report diverse organic phases (particle-like, adhering-like, and inclusion-like) on the surfaces of lunar regolith grains returned by the Chang'e-5 and Chang'e-6 missions. They are predominantly amorphous carbon-like, containing N- and O-bearing functionalities and amide (─CONH─) linkages. The lunar organics show δD, δ¹³C, and δ¹⁵N values more negative than those of insoluble organic matter reported in carbonaceous chondrites and asteroids, consistent with impact-induced evaporation-condensation and surface reworking. The presence of solar wind implantation signatures in the organics supports long-term exposure on the lunar surface. Together, these findings suggest that the impacts both delivered and chemically processed organic matter on the lunar surface, generating N- and O-bearing functionalities.

Robust real-time gas sensing is important for many fields, including agriculture and health care analysis of breath/biofluid volatiles. Ammonia is ambiently present at parts per billion (ppb) to parts per million (ppm) levels, but current detection technologies suffer long measurement times, instability, cost, and issues with selectivity. Here, surface-enhanced Raman spectroscopy (SERS) is markedly improved through precision precleaning protocols, which allow surface sensitization of the metal facets using a water monolayer. Harnessing monolayer aggregates of densely packed gold nanoparticles with sub-nanometer spacing defined by rigid scaffolding molecules gives sub-ppm detection of ammonia at room temperature. Accessing the poorly studied high-wave number [>2500 per centimeter (cm^-1)] region provides much improved discriminatory capabilities, enabling us to generalize this approach to a range of volatile organic carbon (VOC) molecules including ethanol, methanol, and acetone.

Continental intraplate magmatism through time has played a crucial role in ancient mass extinctions, landscape evolution, global climate, and volcanism. These magmatic systems are also crucial sources of critical metals, including the rare earth elements (REEs). Nonetheless, the origins of alkaline intraplate magmas, such as carbonatites, remain enigmatic. Here, we use kinematic plate modeling to show that ~35% of the present-day subcontinental lithospheric mantle has experienced substantial subduction-related fertilization in the past 2 billion years. These fertilized mantle domains underlie ~67% of post-1.8-billion-year-old carbonatites and ~72% of magma-related REE ore deposits (and ~92% of Precambrian REE deposits), substantiating a genetic link between the ancient, enriched mantle lithosphere and alkaline intraplate magmatism and associated ore deposits. We find no correlation between the timing of mantle source fertilization and carbonatite formation, indicating that the evolution of these magmas is multistage, including an initial metasomatic "primer" of the mantle lithosphere and a subsequent and disconnected melting "trigger" event responsible for magma generation.

Aromatic π-π stacking interactions are fundamental to protein architecture, molecular recognition, and drug efficacy, yet directly quantifying them under near-physiological conditions has remained challenging. Here, we use a recently developed spectroscopic platform, thermostable Raman interaction profiling (TRIP), that enables direct, label-free detection and quantification of aromatic π-π interactions in complex protein environments. Using the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) main protease (M^pro) as a biologically and clinically relevant model, we demonstrate that subtle changes in the phenylalanine benzene ring breathing (BRB) mode serve as a precise spectroscopic indicator of π-π stacking strength. This signal is highly responsive to both protein concentration-dependent dimerization and ligand-induced structural changes. M^pro forms a catalytically active dimer stabilized by a conserved aromatic triad (phenylalanine-140, histidine-163, and histidine-172), providing an ideal system to interrogate π-stacking at an important protein interface. Potent inhibitors MPI8 and nirmatrelvir produced the strongest BRB spectral shifts, broadening, and intensity changes, consistent with enhanced aromatic stacking and dimer stabilization, whereas halicin and VB-B-145 showed weaker engagement. BRB spectral changes also showed quantitative correlation with dimerization efficiency, published IC₅₀ (median inhibitory concentration) values, and antiviral efficacy in A549-ACE2 cells. Complementary density functional theory revealed electron density rearrangements and vibrational coupling patterns unique to stacked aromatic residues. This integrated spectroscopic-computational approach enables quantitative probing of π-π stacking in native-like protein environments and positioning TRIP as a generalizable tool for designing drugs targeting aromatic protein-protein interfaces.

Electrohydrodynamic (EHD) pumps noiselessly generate fluid flow in dielectric liquids using high electric fields to create, accelerate, and neutralize ions. Such pumps find applications in wearable actuators, soft robotics, and active thermal management. The influence of fluid properties on pressure and flow rate remains poorly understood. We present a systematic comparison of EHD pumping across 11 fluids, including 8 previously unidentified candidates, spanning viscosities from 0.5 to 19 millipascal seconds and dielectric constants from 2.3 to 64. Tests with more than 30 flexible fiber pumps show that low-viscosity and high-dielectric constant liquids markedly enhance pumping performance. For 1.2-millimeter-inner-diameter fiber pumps, replacing the commonly used Novec 7100 with propylene carbonate increased fluidic power density fivefold, reaching 495 milliwatts per cubic centimeter at 4.4 kilovolts. This study identifies key fluid properties for pumping, expands the EHD fluid library, and establishes a rigorous benchmark for performance evaluation, providing guidance for future EHD pump designs.

Nicotine, the principal addictive component of cigarettes, is linked to cognitive decline and neurodegenerative alterations, likely through oxidative stress and impaired iron regulation in neurons. Yet, underlying molecular pathways remain unclear. This study examined the role of pulmonary neuroendocrine cells (PNECs) in smoke-induced neural changes. Using human pluripotent stem cells, we generated induced PNECs (iPNECs) to overcome culture limitations and performed mechanistic analyses. We found that nicotine exposure stimulates iPNECs to secrete exosomes enriched with serotransferrin, an iron-binding glycoprotein. Neurons internalizing these exosomes displayed elevated levels of transferrin receptor 1 (TFR1), divalent metal transporter 1, and duodenal cytochrome b, associated with ferritin accumulation, oxidative stress, and adenosine triphosphate depletion. Inhibition of TFR1 alleviated these effects. Furthermore, nicotine-triggered exosomes increased α-synuclein expression in neurons in a manner consistent with stress- and vulnerability-associated signatures observed in human lungs and nicotine-exposed mice, highlighting PNEC-derived exosomal signaling that may contribute to neuronal dysfunction.