Browse Articles

Endothelial progenitor cells are associated with improved vascular repair in experimental aortic dissection

Climate change, inequality, and childhood stunting in African countries

Childhood stunting is associated with increased mortality, higher risk of chronic disease, impaired cognitive development, lower educational attainment, reduced economic opportunities, and intergenerational transmission of stunting. These risks are likely to intensify as climate change exacerbates key drivers of undernutrition, making it important to understand how rising temperatures affect stunting and the role of socioeconomic inequality in this relationship. We analyze data from 34 African countries from 2004 to 2020 using Demographic and Health Surveys (DHS), combining observed temperature variability from ERA5 reanalysis with anthropogenic temperature anomalies derived from Detection and Attribution Model Intercomparison Project (DAMIP) simulations. Using a mediation framework, we examine pathways linking temperature anomalies, inequality, and child stunting. Results based on observed temperature anomalies show no direct climate effect on stunting or inequality, but a positive and statistically significant association between inequality and stunting. In contrast, anthropogenic temperature anomalies are positively associated with inequality and stunting, with a 1 °C increase linked to a 3.45% rise in child stunting (SE = 1.52, P = 0.023), with no evidence of mediation through inequality. Notably, we find a consistent positive association between inequality and stunting across specifications. These findings suggest that reducing inequality, together with investments in education, sanitation, and household resilience, could substantially lower stunting rates and protect child health in a warming world.

Lineage-specific selection signals in the Growth arrest-specific protein 8 (GAS8) domain protein of Trypanosoma melophagium

Abstract The Growth arrest-specific protein 8 (GAS8) domain-containing gene family (Orthogroup 6127at5690) is a highly conserved, single-copy orthologous group in the Trypanosoma taxa retained for codon-based evolutionary analysis (10 validated species). This family encodes a microtubule-associated protein implicated in cytoskeletal organization and flagellar motility. We conducted a genus-wide evolutionary analysis of the GAS8-domain protein, focusing on the Trypanosoma melophagium ortholog LSM04 004638. Maximum likelihood phylogenetic reconstruction, branch-specific and site-level codon-based selection analyses, ancestral sequence reconstruction, and Rosetta-based energetic estimation were performed. Despite strong purifying constraint consistent with essential cytoskeletal function, branch-level aBSREL detected a statistically significant signal compatible with episodic diversifying selection along the T. melophagium lineage (aBSREL: LRT = 6.72, Holm-corrected p = 0.0494). Site-level analyses identified two significant MEME codon sites (2 and 109; p = 0.00598 and p = 0.00916), corresponding to derived non-synonymous substitutions relative to the reconstructed ancestor (P2G and V106L); a third site (267) was suggestive but not significant (p = 0.08596). Branch-site codeml did not reach statistical significance (LRT = 1.7428, p = 0.1868, BH-FDR = 0.9339), although BEB highlighted site 2 (PP = 0.983) under the alternative model. These results are consistent with, but do not by themselves prove, limited lineage-specific adaptive refinement in an otherwise highly constrained cytoskeletal regulator; the signal should be regarded as method-dependent and statistically modest based on codeml branch-site test. A RELAX sensitivity test found no evidence that the focal-lineage signal is driven by relaxed constraint (K = 1.12, p = 0.697). Rosetta-based energetic comparisons across single- and double-reversion models consistently yielded positive $$\Delta \Delta G$$ values, but structural interpretation remains model-dependent and should be treated as hypothesis-generating rather than as direct evidence for altered function in vivo. 

Resolving Feynman’s restaurant problem reveals optimal solutions and human strategies

In the 1970s, physicist Richard Feynman turned lunch with a friend into a math problem—how to optimize dish selection over multiple meals—but his handwritten notes remained a mystery for decades. Here we present the fully deciphered problem and solution, prove its optimality, generalize it to related problems, and compare the results to human behavior. The optimal policy specifies decreasing thresholds for switching from exploring new dishes to exploiting the best, with thresholds varying based on the distribution of the quality of dishes. We connect these results to the existing psychological literature on optimal stopping problems, which has explored close variants on Feynman’s problem, and use our generalization of the solution to explore how the underlying distribution of the quality of the options influences people’s choices. A preregistered experiment with 2,520 participants shows that people adopt thresholds that decrease linearly with the proportion of trials remaining, consistent with the observation of linear thresholds in other optimal stopping problems. However, we show that people tend to explore more than predicted by linear thresholds, and that different distributions of quality result in thresholds with the same slope but different intercepts. These results indicate that people adapt linear thresholds used in optimal stopping tasks in a way that is sensitive to the underlying distribution—a simple strategy that we show is nearly as effective as Feynman’s solution.

High-speed radiography of laser-induced shock wave generation in a mock explosive

Abstract Short-pulse laser-induced shock waves can produce high-pressure, short-duration mechanical loading in granular energetic media. To quantify this phenomenon, we performed experiments in a standard mock explosive -compressed sucrose- avoiding the handling constraints of explosives. Because the medium is granular and optically opaque, we employed time-resolved synchrotron X-ray imaging to directly observe shock-induced structural evolution. A green nanosecond laser pulse serves as the shock driver. The generation of a shock wave is confirmed by ex-situ tomographic analysis, which also enables quantitative interpretation of the time-resolved data to determine the shock pressure (~ 3.6 GPa) and propagation velocity (~ Mach 4). Furthermore, doping with aluminum nanoparticles enhances laser absorption and increases the resulting shock pressure. These results demonstrate the potential of high-power laser pulses for initiation of detonation in secondary explosives and provide a pathway toward faster, optically-triggered detonator concepts.

Reply to Janssens and Mech: The possibility of natural wolf dispersal to Stora Karlsö

SPINDER: an open-source 18-DoF hexapod robot with hierarchical central pattern generator control and analytic inverse kinematics

Dietary Guinea hen weed (Petiveria alliacea) leaf meal improves growth performance, redox balance and inflammatory indices in rabbits raised under hot-humid tropical conditions

Potassium controls skin adaptation in <i>Candida auris</i>

Comprehensive metabolomic profiling of Egyptian Salvia species reveals promising leads for chemopreventive and anti-inflammatory drug development: In vitro and In silico study

Abstract The vast majority of human malignancies are the result of sustained inflammatory responses. Nowadays, it is well-known that there is a substantial association between inflammation and cancer. The Salvia genus has garnered attention due to its richness of phytochemical profiles with anti-inflammatory and chemopreventive properties. Although the recognized therapeutic potential of Salvia species is recognized, there is considerable variation in their reported chemical composition, and less is known about their compositional differences. In this work, UPLC-HRMS/MS coupled with molecular networking was employed to glean a holistic overview of the chemodiversity of the metabolome of three Salvia species. This was followed by molecular docking of 218 compounds against KEAP1 (PDB: 4IQK) and iNOS (PDB: 1M8D), validated by positive controls. Network pharmacology, Protein–Protein Interaction (PPI), and enrichment analyses identified hub genes (TNF, CASP3, CASP8, PARP1, iNOS, EGFR, PPARG, AKR1C isoforms, and NQO1) linked to inflammatory and antioxidant signaling. Docking analysis predicted that several major compounds may exhibit dual binding affinities, supported by chemoinformatics, ADME, and toxicity predictions. Cirsimaritin was evaluated against AKR1C3 and PARP1 using molecular docking and 100-ns molecular dynamics simulations, representing different stability and interaction profiles between the two targets. The results indicate a dual binding activity, with Cirsimaritin exhibiting primary and stable interaction with AKR1C3 alongside a secondary, dynamic modulatory interaction with PARP1. Mostly bioactive compounds were predominantly found in Salvia multicaulis . The extracts were screened for their in vitro anti-inflammatory and chemoprevention activities. Preliminary experiments confirmed that S. multicaulis acts as an inducer of chemopreventive NAD(P)H: Quinone oxidoreductase 1 (NQO1) protein expression in a murine hepatoma (Hepa1c1c7) chemoprevention model. It also demonstrated the ability to inhibit the lipopolysaccharides (LPS)-induced nitric oxide (NO) production and iNOS protein expression in the RAW264.7 macrophage model. Furthermore, flavonoids and terpenoids were identified to be the major components in this extract, which might be responsible for anti-inflammatory and chemoprevention activities. Our results support the possible application of S. multicaulis in the treatment of human malignancies.

Egress thresholds and wildfire fatalities

Avoiding human fatalities during wildfires is a key public policy objective. Outward road access, or the number of egress routes, is widely assumed to influence wildfire fatalities, yet few studies have quantified if or when this factor becomes critical. To address this gap, we assembled a dataset on community-level wildfire fatality counts and combined it with nationally consistent community egress for the United States, finding that cumulative fatalities are sharply concentrated in communities with very few exits, declining steeply to roughly six nonresidential roads, beyond which additional routes confer minimal further risk reduction. Extending this analysis nationally, we mapped all small communities (&lt;50,000 residents) to identify geographic confluence of limited egress and high wildfire hazard, highlighting regions where road constraints could directly amplify fatalities. Across the United States, 17.7 million people live in communities below this critical egress threshold, including 2.5 million in high wildfire hazard areas. Although most high-risk communities are in the western United States, unexpected hotspots appear in Oklahoma, Florida, and Hawai’i. As wildfire hazard continues to expand with climate change, fuel accumulation, and development in the wildland–urban interface, even more communities may be at risk. Targeted investment in road infrastructure, improved evacuation communication and preparedness, and development of preplanned refuge options together offer complementary and actionable pathways to reduce wildfire fatalities and build nationwide resilience.

Retraction Note: Fractional-order fast terminal sliding mode control of a nonlinear aeroelastic wing section considering gust load

Comprehensive database of track-structure simulations on DNA damage by H–Fe ions up to 1 GeV/u for space radiation biology

Polyphosphate affects the growth and methanogenesis of deep-sea methanogenic archaea

Microorganisms employ inorganic polyphosphate (polyP) as an ancient strategy for energy and phosphate storage, yet its physiological roles in methanogenic archaea remain largely unexplored. Here, we report that polyP metabolism is coupled to growth and methanogenesis in Methanolobus sp. ZRKC1, a representative of eight methanogenic archaea isolated from deep-sea cold seep sediments. Through combined genetic, biochemical, and physiological analyses, we find that PPK1 mediates polyP synthesis in a Mg 2+ -dependent manner, whereas PPK2 functions primarily as a polyP hydrolase. Deletion of ppk1 in strain ZRKC1 abolishes polyP accumulation and impairs both growth and methane production, pointing to a role for polyP as a metabolic hub linking these processes. Transcriptomic profiling reveals that under organic phosphorus conditions, strain ZRKC1 upregulates phosphoesterases to liberate bioavailable phosphate, which is subsequently channeled into polyP via PPK1. Furthermore, in situ transcriptomic data suggest that the genetic capacity for this metabolic strategy may be present and transcriptionally active in the native environment, with concurrent upregulation of genes involved in phosphate acquisition, polyP metabolism, and methanogenesis. Our findings suggest the importance of polyP in linking phosphate homeostasis to growth and methanogenesis in deep-sea methanogenic archaea.

Polyunsaturated fatty acid–derived lipid mediator patterns determine viral pneumonia severity and risk for critical COVID-19

Severe respiratory infections such as COVID-19 are characterized by excessive inflammation leading to the development of pneumonia and acute respiratory distress syndrome. Bioactive lipid mediators (LMs) derived from ω6 and ω3 polyunsaturated fatty acids are central to the regulation of inflammation, controlling both its initiation and resolution. Still, their role in viral infections remains underexplored. By employing a holistic approach involving the analysis of white blood cell transcriptomes, targeted lipidomics, cytokine and immune cell profiling, we now show that LM patterns around hospital admission are profoundly altered in COVID-19, correlate with inflammatory responses, and stratify patients according to disease severity. Central to this are CYP450-derived LMs, such as 20-HETE, and lipoxygenase- or nonenzymatic-associated LMs such as 15-HETE, both exhibiting vasoactive function, along with lipid peroxidation metabolites such as 10-HDOHE. Among them, increased 20-HETE appears to be a promising prognostic biomarker for ICU admission and a potential therapeutic target for severe COVID-19 disease. Our study emphasizes the importance of LM patterns in COVID-19 pathophysiology and sheds light into the broader immune mechanisms beyond cytokines driving viral pneumonia in humans.

Canonical and variant PRC1 functionally converge on PRC2 targets to regulate transcriptional programs during mouse limb development

The developing limb is a classical model system for studying genetic aspects of pattern formation and mechanisms underlying tissue differentiation. The transition from early to differentiated cell fates during limb bud development requires the precise spatial and temporal regulation of gene activation and silencing programs. However, how transcriptional silencing of early genes is achieved remains poorly understood. Here, we investigate the role of the Polycomb Repressive Complexes (PRC1 and PRC2) in this transcriptional transition in the developing mouse forelimb. We show that the progression from early (E10) to late (E12.5 distal) forelimb stages is associated with shifts in promoter-proximal SUZ12 occupancy at early developmental genes. Conditional inactivation of Eed results in derepression and ectopic distal expression of early genes, which occurs despite the persistence of RING1B and H2AK119Ub. We further identified that SUZ12/RING1B co-occupied targets were also bound by RYBP-containing variant PRC1, indicating parallel recruitment of canonical and variant PRC1. Functional analyses of the combined inactivation of EED and RING1B reveal severe limb malformations and significant gene derepression, exceeding the effects of single EED or RING1B inactivation. Together, our findings demonstrate that the functional convergence of canonical and variant PRC1 at key developmental loci is required to maintain robust transcriptional silencing and regulate transitions in gene expression programs required for proper limb morphogenesis.

Memory, chaos, and noise in ecological forecasting

Ecological populations fluctuate for reasons that are often ascribed—separately—to historical legacies, intrinsic nonlinear dynamics, or stochastic noise. Yet these forces rarely act in isolation. We assembled a global database of 302 abundance time series spanning birds, mammals, fishes, insects, and plankton to ask how memory, nonlinearity, and dynamical stability interact to shape predictability. We used empirical dynamic modeling to estimate the memory length and classified time series stability via effective Lyapunov exponents. We also examined the degree to which incorporating memory and nonlinearity reduce apparent noise and improve prediction. We found that memory length was greatest in neutrally stable series and proportional to the Lyapunov horizon in chaotic series. Both memory and nonlinearity improved forecasts, but gains were largest in series exhibiting positive Lyapunov exponents (oscillations and chaos). By contrast, populations with strongly stable dynamics are well captured by low dimensional linear models. Hence, nonlinearity and memory are both important components of ecological dynamics and the effective Lyapunov exponent is a useful prognosticator of predictability.

Reply to Lemieux et al.: Integration does not preclude essentiality of mitochondrial glycerol-3-phosphate dehydrogenase

Trace fossils constrain the perceptual ranges of the earliest motile animals

The late Ediacaran marks a pivotal interval in early animal evolution, when benthic organisms began engaging with increasingly heterogeneous and dynamic seafloor environments. These shifts signal the emergence of more sophisticated locomotory and sensory capacities, yet the perceptual capacities of early motile animals remain poorly resolved because body fossils from this interval rarely preserve diagnostic sensory organs, if such structures existed. However, trace fossils offer a complementary archive, directly recording the behavioral consequences of perception, but quantitative estimates of sensory mechanisms and effective perceptual ranges have remained out of reach. Here, we estimate perceptual/sensory distances in over 230 Ediacaran–Cambrian tracemakers by integrating persistent homology analysis of trace fossils with numerical simulations of cue-gradient-driven foraging. Persistent homology captures perceptual coverage across spatial scales, providing a topological analog for integrated sensing and space-filling navigation. Simulations based on Gaussian distance-weighted sensory integration reveal a strong linear relationship between perceptual distance and the centroid of the persistence curve, enabling direct inference of sensory distance from fossilized movement paths. Application of this framework to stratigraphically constrained looping trails reveals an exponential expansion of sensory distance from millimetric contact-based sensing, subcentimetric chemo-/mechanosensation to decimetric long-range visual-sensation by the terminal Ediacaran. This expansion transformed environmental cues from locally random noise into structured, exploitable signals, shifting animal–environment interactions from passive response to active selection. Such restructuring of early benthic information landscapes provided a biological and ecological foundation for intensified bioturbation, niche diversification, and the increasingly complex species interactions that foreshadowed the Cambrian Explosion.

Rethinking energy transition strategies for the European Union amid rising energy prices

Geopolitical tensions and the disruption of major energy imports have sharply elevated energy prices across the European Union (EU), creating a persistent energy supply gap and posing long-term challenges for energy security. Here, we introduce a comprehensive framework integrating the advanced Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model with a system dynamic WILIAM (“Within limits”) Integrated Assessment Model to systematically evaluate strategies for closing this energy gap. We find that measures to close the energy gap in the short term exacerbate either economic or public health burdens, highlighting the need for more sustainable solutions in the long term. Our further analysis shows that long-term strategies focused on renewable energy transitions not only close the energy gap but also bring net benefits equivalent to ~3% of projected GDP for 2050. Moreover, we find that rising energy prices substantially influence the cost-effectiveness of accelerated energy transitions. Under current high energy price levels, the benefits from achieving energy targets set for 2050 by 5 to 20 y in advance could outweigh the additional costs. The consideration of dynamic trends in the levelized cost of electricity (LCOE), particularly under rapid renewables expansion, is critical for avoiding overly optimistic estimations of green transition benefits. Our findings suggest that a timely transition to renewable energy benefits the EU in the face of the energy crisis, and policies proactively adjusting energy prices could facilitate a greener, more sustainable future.