Browse Articles

An impedance-decoupled tube-bundle metamaterial with porous lining for deep-subwavelength broadband low-frequency absorption

This paper proposes a novel embedded tube-bundle panel with porous lining acoustic metamaterial for high-efficiency broadband sound absorption in the sub-500 Hz regime at deep-subwavelength scales. A physics-informed analytical model based on double-porosity theory and the transfer-matrix method is developed and validated through finite element simulations. An impedance decoupling strategy is introduced to independently regulate acoustic resistance and reactance by tuning the geometric parameters of the tube bundles under a constant panel perforation ratio, thereby enabling flexible control of both the resonance frequency and absorption bandwidth. The effects of tube diameter, tube length, porous lining thickness, and the static flow resistivity of the porous material on sound absorption performance are systematically investigated. The results show that the tube bundles modulate low-frequency resonance to localize acoustic energy, while the porous-lined back cavity provides dominant dissipation; their synergistic resonance–dissipation mechanism leads to efficient broadband absorption. Using the proposed impedance decoupling strategy, a parallel multi-unit absorber with a total thickness of only 50 mm (1/26 of the wavelength) is constructed and experimentally validated. The absorber achieves continuous high-efficiency absorption, with an average coefficient of 0.941 over 259–480 Hz (α > 0.9). This work provides a physics-informed and scalable design framework for compact and tunable acoustic metamaterials targeting broadband low-frequency noise control.

Chromatin end–anchored chromosome-sized domains and promoter loops organize a transcriptionally active genome in <i>Tetrahymena</i>

Three-dimensional (3D) genome architecture shapes gene regulation, yet the folding principles of compact unicellular genomes remain unclear. Among unicellular eukaryotes, the ciliate Tetrahymena thermophila provides a distinctive model, harboring a transcriptionally active somatic macronucleus (MAC) with a genome fragmented into gene-dense minichromosomes and a silent, intact germline micronucleus. To delineate macronuclear chromatin organization, we integrated nucleosome-resolution Micro-C, ATAC-seq, and RNA-seq across the Tetrahymena life cycle. We find that macronuclear chromosomes form chromosome-sized interaction domains rather than canonical A/B compartments or internal TAD-like hierarchical structures. Each macronuclear chromosome behaves as a telomere-bounded structural unit organized by two major features: Highly accessible telomere-capped ends form stable end–end interaction hubs, and promoter-proximal open chromatin sites anchor long-range internal promoter-centered loops whose strength correlates with transcriptional activity. During conjugation, the sexual life cycle of Tetrahymena , long-range internal loops, and promoter–promoter contacts are transiently diminished and subsequently restored in later conjugation stages, whereas chromosome end–end contacts remain relatively stable. A similar architecture is observed in the related ciliate Tetrahymena pyriformis , indicating conservation within the genus. Together, our results define a compact, end-anchored, and promoter-centric genome-folding strategy that organizes a fragmented, gene-dense, transcriptionally active genome without the canonical compartment/TAD hierarchy seen in metazoan genomes. These findings expand the known repertoire of eukaryotic 3D genome architectures and suggest that promoter-associated transcription hubs can evolve independently in divergent eukaryotic lineages.

Comparative evaluation of major cropping patterns in coastal saline-alkali lands: Economic, ecological, and social benefits

Soil salinization constrains agricultural productivity in coastal regions. A two-year field experiment in the coastal saline-alkali farmland of Tangshan, China evaluated three locally adapted cropping patterns: fresh edible pea-rice rotation, rice-crab co-culture, and wheat-rice rotation, with conventional monocropping systems as controls. The fresh edible pea-rice rotation increased net income by 94.78% compared with rice monoculture. The rice-crab co-culture generated the highest economic return, with net income ranging from 24,000–53,400 CNY ha  −   1 . The wheat-rice rotation increased net income by 49.8% compared with wheat-maize rotation and by 180.64% compared with rice monoculture. In addition, the cropping patterns showed trends of reduced soil salinity (by 0.13%–0.20% in total soluble salt content) and increased soil organic matter (by 0.20–0.30 percentage points) relative to controls, significantly reduced pesticide inputs by 20%–50% (P &lt; 0.05), and exhibited nitrogen and phosphorus loss reduction rates of approximately 15%–25%. These results demonstrate that optimized cropping patterns can simultaneously enhance economic performance and ecological sustainability in coastal saline-alkali agriculture, with soil quality improvements showing promising trends over the two-year study period.

Hallucination in Time-series Large Language Models: An empirical lnvestigation and analysis of mitigation strategies

Design of ultra-thin broadband sound-absorbing metamaterials based on Helmholtz resonators

Achieving efficient low-frequency sound absorption within limited thickness remains a persistent challenge in acoustic engineering. In this work, an ultra-thin broadband absorber is developed by exploiting the weak coupling interaction among Helmholtz resonant units. Instead of relying on bulky cavity enlargement, the proposed design establishes a gradient distribution of resonant frequencies through deliberate modulation of geometric parameters, enabling broadband performance via spatially compact arrangements. Numerical simulations reveal that the two configurations exhibit high absorption efficiency (sound absorption coefficient &amp;gt; 0.8) over 480–1023 and 300–500 Hz, respectively. Despite their compact geometries, the overall thicknesses are restricted to 32 and 42 mm, corresponding to only 1/10.6 and 1/27 of the minimum operating wavelengths. To verify the predictive model, impedance tube measurements were carried out independently for both structures. The experimental results closely follow the simulated trends, confirming the reliability of the analytical and numerical framework. The proposed designs, therefore, demonstrate effective subwavelength absorption capability across targeted mid-low and low-frequency ranges.

Virtual ultrasound machine operating in a GHz to MHz frequency range for particle-based biomedical simulations

Ultrasound–matter interactions underpin numerous biomedical and soft-matter applications, yet simulating these phenomena is challenging due to the large separation of viscous and sonic time scales. Continuum methods capture large-scale wave propagation but cannot resolve microscale interactions, while particle-based approaches offer molecular resolution but struggle with efficiency and stability at larger scales. We introduce a particle-based virtual ultrasound machine that uses a smoothed dissipative particle dynamics variant with an implicit pressure solver and a negative-pressure stabilization scheme, required to mimic acoustic propagation across medically relevant MHz–GHz frequencies. We demonstrate its capabilities by modeling the acoustophoresis of encapsulated microbubbles, a key mechanism in ultrasound-mediated drug delivery. Beyond this application, the approach establishes a generalizable platform for simulating wave–matter interactions in soft and biological materials, opening promising directions for computational studies of acoustics-driven phenomena in science and engineering.

The perception and experience of dignity in the care of older adults in nursing homes: A Meta-aggregation protocol

Background The concept of dignity in the context of nursing home care for older adults remains vague, hindering further research in this area. Aim This systematic review aims to conceptualize the characteristics of dignity in nursing home care for older adults, with attention to Chinese cultural perspectives. Methods The six international databases SCOPUS, PubMed, CINAHL, Embase, Ovid, and PsycInfo, and one Chinese database CNKI will be searched from inception to 31st August 2025, and eligible studies will be primarily evaluated. The literature selected will focus on primary studies that explore older adults’ perceptions of dignity who have resided in the nursing home for at least one month, encompassing their experiences and the factors influencing dignity. This review will draw exclusively on peer-reviewed journal articles, with no language restrictions applied. Grey literature — including dissertations, theses, conference proceedings, and institutional reports — will not be considered for inclusion. The systematic review will adhere to the PRISMA 2020 guidelines and will be registered with PROSPERO. Three reviewers (a lead researcher, a graduate student assistant, and a non-nursing assistant) will primarily screen the titles and abstracts separately. And two professional reviewers (the lead researcher and the graduate student assistant) continue to select studies and extract data independently following the predesigned data extraction forms. Any discrepancies will be documented and resolved by a third external reviewer until consensus is reached. The quality of the included literature will be assessed using the Joanna Briggs Institute (JBI) critical appraisal tools, and the findings will be synthesized using the meta-aggregation approach. Expected outcomes This review is expected to identify key themes across two domains: inherent dignity (satisfying physical needs) and social dignity (individuality, identity and independence). It will also identify the key factors influencing dignity, including personal factors (functional status), organizational factors (staff attitudes, organizational ethical environment), and sociocultural factors (Chinese cultural norms such as collectivism). The results of the dignity in care will help healthcare providers implement dignified care in nursing homes.

The analogy theorem in Hoare logic for formal verification of knowledge transfer in machine learning

Si-implanted ohmic contacts with modulated pulse activation annealing for down-scaled RF GaN HEMTs

A modulated pulse annealing method combined with an Al2O3/SiNx annealing cap is utilized for activating implanted Si in n+ ohmic contacts for AlGaN/GaN HEMTs. The objective is to prevent GaN decomposition during annealing and to reduce the alloying temperature of ohmic contacts. This enables the alloying of SiNx-encapsulated contacts for obtaining smooth ohmic contact edges, which is important for downscaled Ka/K-band HEMTs with a short gate–source distance. Al2O3 functions as a diffusion barrier against nitrogen, and SiNx protects the epitaxial layer stack during cap etching and prevents GaN decomposition due to the loss of N. Furthermore, the Al2O3/SiNx cap acts as a retardation layer for Si implantation to achieve a maximum Si concentration in the GaN channel under the AlGaN barrier. Before activation annealing, H is outgassed from the amorphous Al2O3 at 500 °C, which is then crystallized at 900 °C for enhancing its strength. Then it follows the modulated pulsed activation annealing with five pulses peaking at 1250 °C, four pulses at 1300 °C, and one at 1325 °C. The Al2O3/SiNx cap is then removed with dry and wet etching to leave a clean surface, before the deposition of a Ti-based ohmic contact metal. At an implantation dose of 3.5 × 1015 cm−2, 27% activation is achieved without any GaN decomposition, providing a contact resistance of 0.32 Ω mm after contact alloying only at 650 °C for 5 min.

Rapidly evolving composition of nebular infall recorded by magnesium isotopes in refractory inclusions

The 26 Al- 26 Mg systematics in calcium–aluminum-rich inclusions (CAIs)—the oldest known Solar System solids—has traditionally been used to provide high-resolution temporal constraints on the early Solar System evolution. More recently, the study of variations in the initial Mg isotope composition has emerged as a means to probe for potential compositional heterogeneity in the nascent solar nebula. Here, we report high-precision magnesium isotope data for a collection of 19 CAIs that captures the diversity of refractory inclusions. The data reveal widespread Mg isotope heterogeneity prior to 26 Al decay, covering a large range from −0.285 to +0.088‰. Combined with literature data, the distribution of Mg isotope heterogeneity in CAIs forms a continuum and no longer defines distinct populations. Our findings therefore suggest a continuous CAI formation process that captured a rapid temporal change in the composition of infalling material from the parental molecular cloud of the Solar System.

A rhombus–keyhole shaped circularly polarized dual-band implantable antenna with low SAR compliance

A compact dual-resonance implantable antenna with circular polarization (CP) has been proposed in this paper for bio telemetry applications. The antenna, with dimensions of 9   ×   9   ×   1 . 2 7   m m 3 , is designed using a reversed L-shaped patch, dual key-hole shaped structures and a central rhombus-shaped element. A shoring pin is employed to achieve dual-band resonance, while structural modification enables circular polarization. The proposed antenna resonates at 1.4 GHz (WMTS band) and 2.45 GHz (ISM band). The antenna is fabricated and measured using minced pork meat and saline solution. The measurement results show good agreement with the simulation results. Further, the SAR analysis and link budget analysis, prove that the antenna is suitable for real-time applications.

Significant variability in virulence factors and antibiotic resistance of uropathogenic Escherichia coli strains may be counteracted by their susceptibility to lytic bacteriophages

A Tutorial on Bayesian analysis of linear shock compression data

Gas gun and other shock compression experiments often produce shock wave velocity measurements that are linearly associated with particle velocity. Traditionally, this empirical relationship is quantified with a single Hugoniot curve that is estimated using least squares regression. However, for downstream modeling and simulation tasks, it is often more useful to have multiple Hugoniot curves in the pressure–volume plane that are consistent with the data. We employ Bayesian uncertainty quantification methods as a framework for propagating measurement uncertainty through to model parameters and predictions. Specifically, this Tutorial shows how to sample multiple Hugoniot curves in the pressure–volume plane that are consistent with the shock wave-particle velocity measurements in a two-step Bayesian approach. First, we obtain an analytical expression for the posterior distribution of the linear model parameters using Bayesian linear regression. Second, we propagate samples from the posterior distribution through the Rankine–Hugoniot equations to yield Hugoniot curves in the pressure–volume plane. The procedure is demonstrated with publicly available data on argon, copper, and nickel, and compared against bootstrapping and linear regression. The Bayesian procedure is shown to be interpretable, computationally inexpensive, and less sensitive than an alternative bootstrapping approach to the removal of the point in the copper dataset that has the largest particle velocity. As a Tutorial on Bayesian methodology for the shock compression community, we provide several derivations and explanations that make this paper self-contained, and make all code and data available at github.com/llnl/BALSCD.

<i>N</i> -(3-methylbutyl)acetamide mediates male–male courtship in <i>Bactrocera dorsalis</i> through behavioral threshold modulation

Male–male courtship, observed across diverse taxa, is often regarded as an evolutionary paradox. Here, we address this paradox by demonstrating that such behavior in the globally invasive pest Bactrocera dorsalis arises as a byproduct of a context-dependent shift in the mating filter. We identify N -(3-methylbutyl)acetamide (MBA) as a critical signal that accumulates under high male density and female scarcity. At a threshold amount (~ 1,800 ng), MBA broadens the male’s mating filter, lowering the acceptance threshold for potential partners, thereby elevating courtship motivation and inducing hyperactivity. This broadened filter enables males to court suboptimal but potentially available females (e.g., mated or older individuals) that would otherwise be ignored, while also incidentally triggering male–male courtship. This behavioral shift is rapidly reversible upon encounter with virgin and young females, preserving an innate preference for these optimal partners. By identifying MBA as a chemical signal of mate unavailability, we reinterpret male–male courtship as a neutral byproduct of an adjustment of the mating filter under female scarcity, a trade-off between maximizing mating opportunities and accepting the incidental cost of misdirected courtship. This work bridges behavioral ecology with physiology, offering a mechanistic framework for how social environments dynamically reshape mate acceptance thresholds.

Limited diagnostic utility of albumin-corrected calcium in the intensive care unit: A prospective comparison with ionised calcium

Background Albumin-adjusted calcium is widely used despite uncertainty about its accuracy in critically ill adults. We prospectively evaluated the diagnostic performance of total calcium and of multiple published albumin-correction formulae against ionised calcium, the physiological reference standard, in an intensive care unit (ICU) cohort. Methods In this prospective observational cohort study, ionised calcium (iCa), total calcium, albumin, venous pH, creatinine, estimated glomerular filtration rate (eGFR), C-reactive protein (CRP), procalcitonin, magnesium, phosphate and vitamin D were measured simultaneously. The primary outcome was the diagnostic accuracy (area under the ROC curve [AUC]; sensitivity/specificity) of total calcium and of corrected calcium for detecting hypocalcaemia, defined a priori by the reference standard as iCa &lt; 1.12 mmol/L; the pre-specified contrast was the difference between the two correlated AUCs. Twelve published measures were compared (total calcium; Payne; simplified Payne; Orrell; Berry; James; Jain; Thode; and the Pekar and Antonio estimators). Agreement, formal subgroup interaction tests, an explanatory multivariable model with collinearity diagnostics, and an exploratory internally-validated ICU equation were assessed. Results In total, 250 patients were enrolled (median age 70 years; 147 men, 58.8%). Hypocalcaemia prevalence was 58.0% (n = 145). Payne-corrected calcium correctly identified only 15.2% of truly hypocalcaemic patients (Cohen κ = 0.08), versus 62.8% for total calcium (κ = 0.40). No simple albumin-correction formula significantly outperformed unadjusted total calcium (AUC 0.69–0.75; all DeLong p &gt; 0.05 vs total calcium AUC 0.74). Only the four-variable Pekar estimator achieved a higher AUC (0.78; p = 0.005). In the explanatory model, only total calcium, pH, and sex independently predicted iCa (all variance inflation factors &lt; 1.8); albumin, phosphate and vitamin D were not significant. An exploratory ICU-specific equation reached an optimism-corrected R² of only 0.17. Conclusions Albumin-corrected calcium, including all established formulae tested, provides no diagnostic benefit over total calcium in the ICU and frequently masks true hypocalcaemia. Direct ionised-calcium measurement should be prioritised when accurate calcium status affects management. These are diagnostic-accuracy findings; their clinical-outcome implications require outcome-anchored study.

Genetic diversity and population structure of marigold (Tagetes erecta L.) pre-breeding lines revealed by morphological traits and microsatellite markers

Robust <i>in situ</i> calibration of broadband terahertz time-domain polarimetry systems using a leaky wire grid polarizer

Polarization-sensitive measurements provide rich information about material properties and enable a wide range of applications. Accurate calibration of polarimetry and ellipsometry systems is especially important in broadband spectral imaging instruments, where the performance of polarizers varies with frequency and manufacturing tolerances can introduce systematic errors. Terahertz time-domain polarimetry (THz-TDP) offers amplitude and phase information across a broad spectral range that encompasses many low-energy resonances of chemicals, yet THz polarimetry remains less developed than its infrared and optical counterparts. In this work, we present a generalized in situ calibration technique for THz-TDP imaging systems that uses a rotating polarizer placed over a reference mirror. The method accounts for the leaky, frequency-dependent response of the wire grid polarizer and simultaneously extracts the polarizer response and system calibration parameters from the same measurement. We implement the approach on a handheld polarimetric THz scanner and demonstrate that including a leaky polarizer model yields more consistent and accurate calibration parameters across spectrum and the field of view, as compared to a simple model of an ideal polarizer. The method is validated using two wire grid polarizers with different extinction ratios, illustrating that an accurate in situ calibration can be achieved even when the polarizer response is imperfect and unknown a priori.

IVT-free, chemically synthesized protein-encoding RNA oligonucleotides for rapid production of personalized cancer vaccines

Personalized mRNA neoantigen vaccines demonstrate great potential in cancer therapy, but their customization typically requires more than three months, risking the loss of the optimal therapeutic window for patients. This delay is primarily due to the reliance of current mRNA vaccine production on plasmid fermentation and in vitro transcription (IVT), which involve multiple complex steps. Chemically synthesized RNA oligonucleotides, such as antisense oligonucleotides (ASOs), are produced sparing DNA templates or IVT, thus enabling rapid manufacturing. However, ASOs are limited in length, which precludes their ability to encode proteins. Here, we introduced a 39 nucleotides cap-independent translation enhancer (CITE) element termed BBV that can drive RNA translation. Furthermore, BBV was compatible with efficient rolling circle translation (RCT). We chemically synthesized RNA oligonucleotides containing BBV and gene of interest (GOI) with characteristic 5’-OH and 3’-P termini, which could undergo circularization by endogenous RtcB RNA ligases and efficiently encode proteins through RCT in mammalian cells. We designated these RNA oligonucleotides as Protein-Encoding RNA Oligonucleotides (PEOs). Notably, compared with IVT-produced RNAs, PEOs contained undetectable levels of proinflammatory double-stranded RNAs and exhibited minimal immunogenicity. We further demonstrated that PEO-OVA (encoding OVA antigens) significantly inhibited tumor growth comparable to mRNA vaccine. In an orthotopic glioma model, PEO vaccine also exhibited therapeutic benefits with checkpoint blockade therapy. This study establishes an IVT-free RNA vaccine platform that enables rapid, safe, and highly druggable manufacturing of personalized cancer vaccines, offering substantial potential for clinical application.

Does financial literacy matter for firms? An empirical investigation on Sri Lankan SMEs

Small and Medium Enterprises (SMEs) are vital to economic growth and job creation, especially in developing countries. However, their potential is not fully utilized due to challenges related to limited financial inclusion, poor resource management, and underdeveloped capital markets. Though financial literacy is well-researched in personal finance, its role as a knowledge resource at the firm level and its impact on firm performance remain underexplored. This study investigates the influence of owner-managers’ financial literacy on firm performance, focusing on the mediating roles of FinTech adoption and access to finance. By taking a sample of 264 SME owner-managers in the Western Province of Sri Lanka, this study found that financial literacy significantly enhances firm performance ( β  = 0.241, p  &lt; .01). The findings indicate that financial literacy supports sound financial decision-making and risk mitigation and is positively associated with both FinTech adoption ( β  = 0.542, p  &lt; .001) and access to finance ( β  = 0.533, p  &lt; .001). These results underscore the necessity of enhancing financial literacy and promoting FinTech adoption to fully realize the potential of SMEs within developing economies. The study contributes a concise yet impactful framework for enhancing the performance of SMEs through the strategic application of financial literacy. Based on the study’s findings, it is recommended that enterprise owners and managers prioritize achieving an adequate level of financial literacy. Furthermore, governmental institutions should revise their financial literacy programs, reconsidering their design and implementation strategies to effectively engage key personnel within enterprises. Current programs appear underutilized due to deficiencies in depth and practical applicability of the knowledge given in them.

Full-scattering-matrix deterministic phonon boltzmann transport simulation

Abstract Solutions to the phonon Boltzmann transport equation under the relaxation-time approximation (RTA) are fundamentally limited in that they do not account for the off-diagonal elements of the scattering matrix, which encode intermode energy redistribution. We find that the phonon in-scattering matrix is globally incompressible, requiring nearly its full rank for any useful Frobenius accuracy. The incompressibility worsens as the Brillouin zone is refined. We show that, despite this difficulty, one can develop a computationally efficient 3D BTE solver incorporating the complete scattering matrix by leveraging our two structural discoveries: the non-equilibrium phonon distribution inhabits a remarkably low-dimensional subspace of mode space regardless of how many phonon modes exist, and the leading singular modes of the scattering operator align selectively with this transport-active subspace. Consequently, truncation incurs negligible transport error even under large norm error. The phonon streaming operator’s mode-diagonal character further motivates a hybrid architecture that exploits these two properties. When applied to nanoscale structures emulating a fin field-effect transistor, our BTE solver quantifies a geometry-independent multiplicative correction to the temperature rise predicted under RTA. Our theoretical work and resulting BTE solver help enable rigorous study of phonon transport and systematic design of devices and structures in the ballistic and quasi-ballistic phonon transport regime.