Volume 2 2026
Synthetic Genetic Toggle Switch Robustness to Transcriptional Noise: Design Rules for Bistable Gene Circuit Engineering in Escherichia coli
Clara M. Hoffmann; Rohan T. Iyer; Sasha K. Petrov
This study investigates design rules governing bistability robustness to transcriptional noise in synthetic genetic toggle switches implemented in E. coli, using a library of 48 toggle variants with tuned promoter and ribosome binding site strengths within the context of synthetic biology and gene circuit engineering, an area of growing scientific importance given its implications for synthetic memory device design, bistable genetic sensor engineering, and noise-tolerant gene circuit design principles for cell therapy. Using flow cytometry bimodality quantification, single-cell time-lapse microscopy of state transitions, and stochastic gene expression modeling (Gillespie SSA) for noise tolerance prediction across 48 toggle variants, we examine bistability arising from mutual repression of two transcription factor modules (TetR/LacI), with toggle robustness to noise governed by the ratio of repressor binding affinities and cooperative Hill coefficients at each operator in 48 toggle switch variants characterized in n=3 biological replicates (>50,000 cells per replicate by flow cytometry) with 24-hour time-lapse microscopy for state-switching kinetics in n=200 single cells per variant drawn from E. coli MG1655 at 37 C in M9 minimal medium with arabinose/IPTG inducers for toggle state control; flow cytometry at BD FACSAria III. Results indicate that bistability robustness peaks in a defined promoter-RBS strength window (Ptet 40-60 AU, RBS 20-40 AU) achieving bimodality index >0.84 with spontaneous switching rate <0.002/generation; outside this window 62% of variants show monostability or high switching rates (p < 0.001), with BI >0.84 in optimal window; <0.002/generation switching; 62% failure outside window as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to synthetic biology and gene circuit engineering and carry actionable implications for the design of programs and policies targeting synthetic memory device design, bistable genetic sensor engineering, and noise-tolerant gene circuit design principles for cell therapy.
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Fifteen-Minute City Implementation, Active Mobility Mode Share, and Neighborhood-Level Social Equity: A Multi-City Comparative Study of 24 European Urban Cores
Annika M. Sundqvist; Lorenzo T. Esposito; Fatima K. Al-Hashimi
This study investigates 15-minute city implementation fidelity, active mobility mode share change, and neighborhood-level socioeconomic equity in access improvements across 24 European urban cores with formally adopted 15-minute city frameworks within the context of urban planning and sustainable mobility research, an area of growing scientific importance given its implications for 15-minute city policy design, equity-centered active mobility investment prioritization, and urban proximity index methodology for comparative evaluation. Using 15-minute proximity index (15MPI) computed from OSM network + POI data for each city, regressed against observed active mobility mode share change (cycling + walking trips) and equity access gap between lowest and highest income quintiles, we examine proximity-led urban design increasing walkable access to daily needs reducing need for motorized trips, with cycling/walking infrastructure investment amplifying active mode shift, moderated by socioeconomic barriers to active mobility in lower-income neighborhoods in 24 cities across 12 European countries with pre-post mobility survey data (mean n=12,400 respondents per city), 15MPI computed at 250 m resolution for all residential parcels drawn from 24 cities including Paris, Barcelona, Amsterdam, Vienna, Copenhagen, Helsinki, and 18 others with formally adopted 15-minute city policies and at least 2-year post-implementation data. Results indicate that 15MPI increase of 10 points is associated with 4.2 percentage point increase in active mode share (p<0.001, R2=0.62) but access gains are 38% larger in highest income quintile neighborhoods; lower-income neighborhoods require additional investment to close equity gap (p < 0.001), with +4.2 pp active mode share per 10 15MPI points; 38% equity gap by income quintile as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to urban planning and sustainable mobility research and carry actionable implications for the design of programs and policies targeting 15-minute city policy design, equity-centered active mobility investment prioritization, and urban proximity index methodology for comparative evaluation.
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Classic Ketogenic Diet Versus Modified Atkins Diet for Drug-Resistant Childhood Epilepsy: Seizure Reduction, Tolerability, and 12-Month Dietary Adherence
Petra M. Vanderberg; Samuel K. Osei; Nadia T. Kowalski
This study investigates comparative seizure reduction, gastrointestinal tolerability, and 12-month dietary adherence in children with drug-resistant epilepsy randomized to classic ketogenic diet versus modified Atkins diet within the context of pediatric neurology and dietary epilepsy therapy, an area of growing scientific importance given its implications for drug-resistant pediatric epilepsy clinical dietary therapy selection, dietitian counseling protocols, and dietary adherence support intervention design. Using open-label randomized controlled trial with seizure diary, monthly EEG, plasma ketone monitoring, and GI symptom scale at 1, 3, 6, and 12 months; intention-to-treat analysis, we examine dietary ketosis elevating blood ketone bodies providing alternative neuronal fuel and reducing neuronal excitability via GABA/glutamate ratio shift, HCN channel modulation, and mTOR pathway inhibition independently of blood glucose in 148 children with drug-resistant epilepsy (mean age 6.4 years, mean 3.8 anticonvulsants failed, 54% focal/46% generalized epilepsy), 74 per arm drawn from pediatric neurology epilepsy clinics at Ridgemont Childrens Hospital and 2 affiliated centers with dietitian-supervised initiation and monthly telehealth follow-up. Results indicate that responder rates at 6 months are 54.1% (KD) vs. 50.0% (MAD), not significantly different (p=0.62); MAD shows significantly better 12-month adherence (68.9% vs. 44.6%, p=0.002) and fewer GI adverse events (p = 0.62 (efficacy); 0.002 (adherence)), with 50% responder rate: 54.1% KD vs. 50.0% MAD at 6 months; 12-month adherence 68.9% vs. 44.6% as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to pediatric neurology and dietary epilepsy therapy and carry actionable implications for the design of programs and policies targeting drug-resistant pediatric epilepsy clinical dietary therapy selection, dietitian counseling protocols, and dietary adherence support intervention design.
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Variational Quantum Eigensolver Resource Estimation for Molecular Hydrogen Chains on Near-Term Fault-Tolerant Hardware: Circuit Depth, Gate Count, and Error Mitigation Overhead
Mikhail T. Orlov; Yuki A. Nakamura; Isabel M. Ferreiro
This study investigates circuit depth, two-qubit gate count, and error mitigation overhead requirements for VQE simulation of hydrogen chains H4 through H16 on near-term fault-tolerant quantum hardware with surface code logical qubits within the context of quantum computing and quantum chemistry, an area of growing scientific importance given its implications for quantum hardware roadmap planning, fault-tolerant quantum chemistry milestone setting, and near-term VQE experiment design for molecular simulation. Using OpenFermion-Cirq VQE circuit construction, T-gate count estimation via Solovay-Kitaev decomposition, surface code logical qubit overhead computation with code distance d=7,11,15, and zero-noise extrapolation error mitigation cost modeling, we examine VQE trade-off between ansatz expressibility and circuit depth, with T-gate overhead scaling as O(N^4) in UCCSD and surface code cycle count scaling as O(T-count * d^2 / p_phys) determining total runtime on fault-tolerant hardware in 5 hydrogen chain systems (H4, H6, H8, H12, H16), 3 surface code distances, 4 ansatz variants (UCCSD, HEA, k-UpCCGSD, ADAPT-VQE), resource estimates for circuit depths up to 10^6 gates drawn from resource estimation performed on classical simulation using PySCF for classical reference energies and Qiskit/OpenFermion for quantum circuit construction and T-gate counting. Results indicate that H8 UCCSD requires 28 logical qubits and 2.84 million T-gates (8.4 million surface code cycles at d=11), yielding estimated 4.2 hours on a 1,000-logical-qubit machine; ADAPT-VQE reduces T-gate count by 58% at identical accuracy (p < 0.001), with ADAPT-VQE 58% T-gate reduction; H8 = 4.2 hours on 1k-logical-qubit machine as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to quantum computing and quantum chemistry and carry actionable implications for the design of programs and policies targeting quantum hardware roadmap planning, fault-tolerant quantum chemistry milestone setting, and near-term VQE experiment design for molecular simulation.
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Wolf Reintroduction, Trophic Cascade Dynamics, and Riparian Vegetation Recovery in Yellowstone National Park: A 28-Year Post-Reintroduction Longitudinal Assessment
Marcus T. Bowman; Elsa K. Lindgren; Priya N. Mehta
This study investigates 28-year quantitative assessment of wolf reintroduction-driven trophic cascade effects on elk browsing behavior, riparian willow and aspen recovery, songbird diversity, and stream channel morphology in Yellowstone National Park within the context of wildlife ecology and trophic cascade research, an area of growing scientific importance given its implications for large predator reintroduction policy, rewilding program design, and long-term trophic cascade monitoring methodology for national park management. Using elk census data, wolf GPS telemetry, riparian willow/aspen height-density transects, songbird point count surveys, and stream channel cross-section measurements at 48 fixed sites on 10-year comparison intervals, we examine wolves suppressing elk density and inducing elk behavioral landscape of fear, reducing browsing pressure in riparian corridors and triggering willow/aspen height recovery, which in turn supports songbird nesting habitat and stabilizes stream banks reducing channel erosion and widening in 48 fixed monitoring transects across Yellowstone Northern Range with annual measurements 1995-2023; 28 summers of songbird point counts (n=240 stations); stream channel resurveyed 1995, 2005, 2015, 2023 drawn from Yellowstone National Park Northern Range (Lamar Valley, Blacktail Plateau, Gardiner Basin) â the primary wolf-elk interaction zone with continuous monitoring since 1995 reintroduction. Results indicate that riparian willow mean height increased 284% from 1995 to 2023 (0.48m to 1.84m), aspen recruitment increased 18-fold, riparian songbird species richness increased from 8.4 to 14.2 species, and stream channel width narrowed 24% at high-wolf-use sites versus 2% at low-use control sites (p < 0.001), with 284% willow height increase; 18x aspen recruitment; songbird richness +5.8 species; 24% stream narrowing as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to wildlife ecology and trophic cascade research and carry actionable implications for the design of programs and policies targeting large predator reintroduction policy, rewilding program design, and long-term trophic cascade monitoring methodology for national park management.
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In Situ Cryo-Electron Tomography of Translating Ribosomes in Chlamydomonas Chloroplasts: Polysome Architecture, Cotranslational Folding Intermediates, and Trigger Factor Binding
Yuki M. Tanaka; Boris T. Schulz; Adaora K. Nwosu
This study investigates in situ cryo-ET visualization of chloroplast ribosome polysome architecture, cotranslational folding intermediate conformations, and trigger factor chaperone binding geometry in Chlamydomonas reinhardtii within the context of structural cell biology and cryo-electron tomography, an area of growing scientific importance given its implications for chloroplast gene expression regulation, in situ structural biology methodology, and cotranslational chaperone mechanism dissection. Using cryo-FIB-SEM lamella preparation, cryo-ET at 300 kV (JEOL CRYO ARM 300) with tilt series ±65 degrees at 2-degree increments, SIRT reconstruction, subtomogram averaging (STA) of ribosomal subunits, and distance analysis of polysome geometry, we examine chloroplast ribosomes organizing into helical polysomes with 8-14 ribosome/polysome adapted for co-translational membrane protein insertion into thylakoid, with trigger factor binding at ribosome exit tunnel stabilizing nascent transmembrane domain folding intermediates in 2,840 subtomogram averages from 184 tilt series (48 lamellae, 6 cells) yielding 4.2 A overall resolution by STA with polysome architecture analyzed from 412 identified polysomes in segmented tomograms drawn from Chlamydomonas reinhardtii CC-124 cells grown in TAP medium under 12h:12h light:dark cycle, cryo-vitrified by plunge freezing, and cryo-FIB-SEM lamellae prepared at MPI Dortmund. Results indicate that chloroplast polysomes adopt stacked-disk architecture (mean 10.8 ribosomes/polysome, inter-ribosome distance 28.4 nm) with trigger factor bound at 68% of actively translating ribosomes; 42% of ribosomes show density consistent with cotranslational folding intermediates at exit tunnel (p < 0.001), with 68% trigger factor occupancy; 42% with folding intermediates; 10.8 ribosomes/polysome mean as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to structural cell biology and cryo-electron tomography and carry actionable implications for the design of programs and policies targeting chloroplast gene expression regulation, in situ structural biology methodology, and cotranslational chaperone mechanism dissection.
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Country-Level QALY Threshold Variation, Pharmaceutical Cost-Effectiveness Acceptance Rates, and Health Technology Assessment Decision Consistency Across 18 High-Income Countries
Ingrid M. Sorensen; David T. Okafor; Mei-Ling K. Chan
This study investigates variation in de facto QALY willingness-to-pay thresholds, pharmaceutical CE acceptance rates, and HTA decision consistency across 18 high-income countries from 2010-2024 within the context of health economics and health technology assessment policy, an area of growing scientific importance given its implications for international pharmaceutical pricing policy harmonization, HTA decision transparency reform, and QALY threshold methodology update for post-COVID health systems. Using systematic review of publicly available HTA decisions with ICER extraction, threshold boundary regression, and inter-country decision consistency analysis using kappa agreement statistics, we examine de facto QALY threshold variation reflecting country-specific GDP per capita, health budget constraints, and political economy of pharmaceutical access rather than explicit welfare-theoretic derivation, producing cross-country ICER acceptance inconsistency for identical interventions in 684 HTA decisions (mean 38 per country) across 18 countries for 248 unique pharmaceutical products with ICER data and positive/negative recommendation outcomes drawn from HTA agency databases: NICE (UK), CADTH (Canada), IQWiG (Germany), SMC (Scotland), PBAC (Australia), TLV (Sweden), and 12 additional high-income country agencies. Results indicate that implied QALY thresholds range from 22,400 USD/QALY (Australia) to 184,000 USD/QALY (United States Medicaid), a 8.2-fold difference; inter-country decision agreement kappa=0.48 (moderate) with oncology products showing lowest consistency (kappa=0.32) (p < 0.001), with 8.2-fold threshold range; kappa 0.48 overall; 0.32 in oncology as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to health economics and health technology assessment policy and carry actionable implications for the design of programs and policies targeting international pharmaceutical pricing policy harmonization, HTA decision transparency reform, and QALY threshold methodology update for post-COVID health systems.
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Semantic Entropy as a Scalable Hallucination Detection Signal in Large Language Models: Theoretical Grounding, Calibration, and Downstream Task Benchmark
James T. Wu; Anika M. Johansson; Dele K. Ogunyemi
This study investigates semantic entropy as a computationally tractable hallucination detection signal in large language models, grounding the method in information-theoretic terms and benchmarking calibration and F1 on five factual QA datasets within the context of machine learning and natural language processing, an area of growing scientific importance given its implications for LLM-powered QA system reliability gating, medical/legal hallucination risk reduction, and uncertainty-aware RAG system design. Using semantic entropy computed as H_sem = -sum p(c)*log p(c) over meaning-equivalent clusters of 20 sampled responses, with calibration (ECE) and hallucination detection F1 compared to logit-based, embedding-variance, and self-consistency baselines, we examine sampling-induced variation in semantically equivalent responses capturing epistemic uncertainty about factual claims, with high semantic entropy indicating model uncertainty signaling potential hallucination independent of confidence calibration artifacts in 24,200 question-answer pairs across 5 benchmarks (TriviaQA 5k, NQ 5k, SQuAD 5k, BioASQ 4.2k, HalluBench 5k) evaluated across 3 LLMs with 20 sampled responses per question = 1.45 million total response tokens drawn from inference via API (GPT-4o, Claude 3.5 Sonnet) and local A100 cluster (Llama 3.1-70B) with semantic clustering via SentenceBERT cosine similarity threshold 0.84 for equivalence. Results indicate that semantic entropy achieves mean AUC 0.82 across 5 benchmarks and 3 LLMs (vs. 0.68 self-consistency and 0.64 logit-based), with ECE 0.06 vs. 0.18 for logit confidence; BioASQ domain shows lowest AUC (0.74) due to synonym-rich medical terminology clustering failures (p < 0.001), with mean AUC 0.82 vs. 0.68 self-consistency; ECE 0.06 vs. 0.18 as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to machine learning and natural language processing and carry actionable implications for the design of programs and policies targeting LLM-powered QA system reliability gating, medical/legal hallucination risk reduction, and uncertainty-aware RAG system design.
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Environmental DNA Metabarcoding for Marine Biodiversity Monitoring: Species Detection Concordance With Traditional Trawl Surveys Across 24 Temperate and Tropical Sites
Sian M. Roberts; Kofi T. Mensah-Baffour; Aiko Y. Nakamura
This study investigates concordance between eDNA metabarcoding species detection and traditional bottom trawl survey catch across 24 temperate and tropical marine sites spanning five ocean regions within the context of marine biology and environmental genomics, an area of growing scientific importance given its implications for cost-effective fisheries stock assessment, biodiversity monitoring network design, and CITES-listed species surveillance in data-poor oceanic regions. Using paired eDNA water sampling (n=3 replicates, 1-L, 0.2 um Sterivex filter) and bottom trawl at 24 sites with 12S rRNA and COI PCR amplicon metabarcoding (Illumina MiSeq 2x300 bp) against FishBase and BOLD reference libraries, we examine fish shedding cellular DNA into water column via mucus, feces, and degraded cells that persists 12-48 hours, enabling sensitive non-invasive detection of species present at low density below trawl catchability threshold in 24 sites x 3 eDNA replicates + 1 trawl per site = 72 eDNA samples and 24 trawl hauls; eDNA detected 848 unique ASVs mapping to 284 named fish species across sites drawn from 24 sites spanning 5 ocean regions: NW Atlantic (n=6), Pacific (n=6), Indian Ocean (n=4), Mediterranean (n=4), Caribbean (n=4) at 20-150 m depth. Results indicate that overall eDNA-trawl Sorensen concordance is 0.72 across 24 sites with eDNA detecting 28.4% additional species absent from trawl (low-density species, cryptic species) and trawl detecting 14.2% additional species not in eDNA (deep benthic species with low water column eDNA shed) (p < 0.001), with Sorensen 0.72; eDNA unique detections 28.4%; trawl unique 14.2% as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to marine biology and environmental genomics and carry actionable implications for the design of programs and policies targeting cost-effective fisheries stock assessment, biodiversity monitoring network design, and CITES-listed species surveillance in data-poor oceanic regions.
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Wildfire Smoke Volatile Organic Compound Emission Factors, OH Reactivity, and Secondary Organic Aerosol Formation Potential Across Western U.S. Fuel Types: A 2020-2024 Airborne Campaign
Natasha M. Bergstrom; Darius T. Achebe; Lucia M. Fernandez-Lopez
This study investigates VOC emission factors, OH radical reactivity, and secondary organic aerosol formation potential of fresh and aged wildfire smoke from six major Western U.S. fuel types quantified by airborne campaign measurements 2020-2024 within the context of atmospheric chemistry and wildfire smoke research, an area of growing scientific importance given its implications for wildfire smoke air quality modeling, emission factor database update for CMAQ and WRF-Chem, and health impact assessment of secondary aerosol formation in affected communities. Using whole-air canister and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) VOC measurements from NOAA WP-3D aircraft with fire CO tracer normalization to emission factors (g/kg dry fuel) and Lagrangian aging analysis, we examine biomass combustion releasing fuel-type-dependent VOC mixtures (furans, phenols, terpenoids, aromatic hydrocarbons) with high OH reactivity driving rapid photochemical secondary organic aerosol formation during daytime smoke aging, amplifying PM2.5 population exposure downwind in 48 wildfire events sampled (2020-2024) with 284 valid plume transects: 142 fresh plume (<30 min) and 142 aged (6-18 hr), measuring >200 VOC species across 6 fuel type categories drawn from California chaparral, California mixed conifer, Oregon/Washington Douglas fir, Idaho sagebrush, Colorado subalpine, and Colorado pinyon-juniper fuel types sampled by NOAA WP-3D from 2020-2024 summer campaigns. Results indicate that total VOC emission factors range from 4.8 g/kg (sagebrush) to 28.4 g/kg (chaparral) dry fuel; chaparral and pinyon-juniper smoke show 3.2x higher SOA formation potential per kg fuel than conifer smoke; aged smoke SOA mass exceeds primary PM2.5 at 8 hours in all fuel types (p < 0.001), with 28.4 vs. 4.8 g VOC/kg; chaparral SOA 3.2x higher than conifer; SOA exceeds primary PM2.5 at 8 hours as the primary quantitative benchmark. Concordance between primary and confirmatory measurement approaches exceeded 93%, validating the analytical framework. These findings contribute empirically to atmospheric chemistry and wildfire smoke research and carry actionable implications for the design of programs and policies targeting wildfire smoke air quality modeling, emission factor database update for CMAQ and WRF-Chem, and health impact assessment of secondary aerosol formation in affected communities.
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