Browse Articles

Interpretable machine learning based on the Charlson comorbidity index predicts 28-day mortality in acute hypercapnic respiratory failure

Quasi-triple bonds and ultrashort Be–Be distances in binary superhalogen clusters [X–Be2(BeX)3–X]− (X = Cl, Br, I)

In computational design, clusters with minimal elemental composition are prioritized for superior gas-phase synthetic accessibility, yet most reported main-group metal clusters exhibiting ultrashort metal–metal distances (USMDs, dM–M < 1.900 Å) require complex ternary or quaternary systems, severely limiting experimental realization. We demonstrate that binary superhalogen clusters [X–Be2(BeX)3–X]− (X = Cl, Br, l) achieve the desired USMD via formation of a quasi-triple bond composed of three 3c–2e bonds between two axial beryllium atoms, resulting in compressed Be–Be distances ranging from 1.832 to 1.851 Å. Their exceptional superhalogen characteristics result from vertical detachment energies (VDEs) of 4.65–4.70 eV, surpassing the threshold (VDE = 3.62 eV) by over 1.00 eV and indicating good stability. Consistently, [X–Be2(BeX)3–X]− (X = Cl, Br, l) are identified as dynamically stable global energy minima exhibiting wide HOMO–LUMO gaps (6.38–6.62 eV), which establish them as promising candidates for experimental validation of USMDs between main-group metals.

The development of mindfulness in martial art kendo players: AfMRI analysis of the triple network

Contact networks encode the ATP-induced dynamic structural asymmetry of condensin head domains

Condensin, a structural maintenance of chromosomes (SMC) complex, plays a central role in genome organization by driving DNA loop extrusion through ATP hydrolysis. Experimental studies have revealed an asymmetric ATP-binding order at the Smc4- and Smc2-linked head domains, but the molecular origin and temperature dependence of this asymmetry remain poorly understood. Here, we combine coarse-grained switching-Gō models with all-atom molecular dynamics simulations to investigate how contact-network architecture in ATP-like states governs the order and thermal sensitivity of ATP-competent pocket formation. We find that the Smc4-associated ATP pocket (ATP1) exhibits higher local contact density and greater thermal stability than the Smc2-associated pocket (ATP2), favoring initial ATP1 pocket formation. As temperature increases, the formation of ATP2-binding-competent conformations becomes increasingly dependent on prior ATP1 pocket organization. Contact-network analysis of ATP-induced conformational transitions identifies specific structural regions that mediate this thermodynamic shift, revealing a temperature-dependent shift from independent to sequential pocket formation, consistent with the experimentally observed ATP-binding order at the two head sites. All-atom simulations provide supporting evidence that ATP1 pockets are highly persistent when the nucleotide is present but destabilize upon removal, whereas ATP2 pockets show greater intrinsic pre-organization in the ATP-absent state yet are less persistent when bound than ATP1 pockets. Together, these results advance a thermodynamic framework showing how contact-network connectivity encodes asymmetric, temperature-sensitive conformational competence for nucleotide engagement in condensin.

Astragalus polysaccharide alleviates diabetic nephropathy via SIRT1-dependent activation of FOXO3a/BNIP3 pathway to enhance podocyte autophagy

Multi-head committees enable direct uncertainty prediction for atomistic foundation models

Machine learning potentials have become a standard tool for atomistic materials modeling. While models continue to become more generalizable, an open challenge relates to efficient uncertainty predictions for active learning and robust error analysis. In this work, we utilize MACE and its multi-head mechanism to implement a committee neural network potential for message-passing architectures, where the committee comprises multiple output modules attached to the same atomic environment descriptors. As with traditional committees of independent networks, the standard deviation of the predictions functions as an estimate of the model’s uncertainty. We show for a range of datasets in custom-build models that the uncertainty of the force predictions correlates well with the true errors. We subsequently apply this concept to foundation models, in particular MACE-MP-0, where we train only the newly attached output heads while keeping the remaining part of the model fixed. We use this approach in an active learning workflow to condense the training set of the foundation model to just 5% of its original size. The foundation model multi-head committee trained on the condensed training set enables reliable uncertainty estimation without any substantial decrease in prediction accuracy.

Delayed dynamics and detoxification in nutrient-phytoplankto-by-product systems: mechanisms driving bloom stability and oscillations

Abstract Phytoplankton blooms emerge from the interplay between nutrient availability, biomass growth, and inhibitory by-products such as toxins or exudates. Here, we develop a mechanistic nutrient–phytoplankton–by-product model that couples Beddington–DeAngelis nutrient uptake, by-product-mediated inhibition, and nutrient-dependent detoxification. Analytical results demonstrate that the system remains biologically feasible and bounded, and that a threshold condition governs bloom initiation. Linear stability and bifurcation analyses reveal how detoxification delays can trigger oscillatory bloom behaviour. Across ecologically realistic parameter regimes, the system tends to a stable coexistence state—either directly or through damped oscillations—rather than exhibiting repeated bloom–crash cycles. Global sensitivity analysis (PRCC and Sobol indices) highlights by-product production, inhibition strength, detoxification rate, toxin-linked mortality, and saturation effects as dominant regulators of stability and damping time. Introducing an explicit ecological delay exposes a critical threshold at which a Hopf bifurcation arises, converting the stable equilibrium into sustained oscillations. Numerical simulations confirm the transversality condition and indicate a supercritical onset. Collectively, these results provide a quantitative diagnostic for distinguishing transient from sustained bloom oscillations and identify measurable ecological processes—particularly detoxification and delayed feedback—that govern transitions between stable and oscillatory regimes.

Electronic structures and optical properties of defective V2O5 unveiled by many-body Green’s function theory

We explore the impact of typical point defects, including oxygen vacancies (Ov) and hydroxyl groups (Hy), on the electronic and optical properties of bulk V2O5 by the many-body Green’s function theory. The electronic bandgap of the pristine V2O5 predicted by the QPGW method is wider than that of the experimental sample by ∼1 eV. We find that the defect effect should be an important factor accounting for this big disparity. According to QPGW, Ov and Hy may cause the bandgap of V2O5 to be narrowed by 0.5 and 0.8 eV, respectively. The DFT+U and HSE06 approaches do not exhibit this phenomenon, as they produce an overly localized distribution of the unoccupied orbitals near the conduction band edge. These orbitals are predicted to be rather delocalized in QPGW, owing to the off-diagonal elements of the self-energy matrix. If choosing a low-cost approach to replace the expensive QPGW, evGW is ideal for determining the position of the Fermi level with respect to the valence band edge, while G0W0 is the best for estimating the gaps between occupied states (including valence bands and the in-gap defect states) and the unoccupied ones. The performance of HSE06 is irregular and not good for the defective systems. Optical absorption spectra of the defective V2O5 evaluated by the Bethe–Salpeter equation based on the G0W0 single-particle levels well reproduce peaks in the infrared region of the experimental spectrum.

Multi-factor authentication and key agreement scheme based on PUF and Chebyshev chaotic map for wireless sensor networks

Computational protocol for emission spectra and PLQY for thermally activated delayed fluorescence derived from sulfur/selenium-incorporated multi-resonant molecules

Full width at half maximum (FWHM) is an important indicator for color purity in molecular optical emission. In addition, brightness is determined by photoluminescence quantum efficiency (PLQY). Thermally activated delayed fluorescence (TADF) can convert the electro-pumped triplet states into emissive singlets. Especially, recent experiments suggest that multiple resonance TADF molecules doped with heavy atoms S/Se could effectively avoid the efficiency roll-off by promoting the reverse intersystem crossing (RISC) process. We propose a computational protocol to evaluate FWHM and PLQY based on quantum chemistry calculations and thermal vibration correlation function formalism, which is of great potential to design highly efficient and color-pure molecules. We further build a robust correlation between the reorganization energy of emission state λS1S0em with FWHM and the inverse of reorganization energy of the intersystem crossing (ISC) process 1/λS1T1 with experimental reverse ISC rate constant kRISCexp, crucial for TADF. Our computational method and findings can be used for the molecular design of organic light-emitting diode materials.

Variance of the root mean square value of the residuals of sine fitting in the presence of additive noise

Abstract The least-squares fitting of a sinusoidal model to a set of data points is a common procedure in signal processing algorithms. A residual is the difference between the value of one data points and the estimated value of that point given by the sinusoidal model. The root mean square (RMS) value of all the residuals is a common metric used in many applications to quantify the goodness of fit. In analog-to-digital conversion, for example, the RMS value is used to compute the number of effective bits. In other applications the RMS value is used to compute the signal-to-noise ratio which measures the amount of noise generated by an electronic circuit such as an amplifier, for instance. Due to the presence of different random non-ideal phenomena affecting the data points, like stimulus signal phase noise, sampling jitter or quantization error, the estimative of the RMS value is uncertain and whose statistical properties are important to evaluate. In this work we focus on the effect that additive noise has on the variance of the RMS value of the residuals. A first exact analytical expression is derived and two easier to use and simpler approximations are proposed. The results presented are validated using numerical simulations employing a Monte Carlo type procedure.

Dissociative ionization of pyrazine: A pathway to reactive interstellar ions

Nitrogen-bearing cyclic compounds play a decisive role in the astrochemistry that prevails during the initial phases of star formation. Photoionization of these species under ultraviolet (UV) radiation leads to the formation of smaller cations. Reactions involving these highly reactive small cations could then form new molecules in the interstellar and circumstellar environments. Here, we report an interesting dissociative ionization pathway of pyrazine under UV irradiation, revealing a pronounced formation of the interstellar C3H3N+ ion compared to the parent cation. The C3H3N+ ion is identified as a key precursor for the synthesis of aromatic hydrocarbons containing nitrogen, such as pyridine and pyrimidine, which are of astrobiological significance. In addition, we also observed other nitrogen-bearing reactive cations and C2H2+. Our findings on the dissociative ionization pathways of pyrazine have implications for the abundances of reactive species in astrophysical media and concern both the top-down and bottom-up approaches of astrochemistry.

Silhouettes, number Location, and cube analysis tests from the VOSP battery reveal visual object and space perception deficits in early Alzheimer’s disease

Bayesian Gaussian process inference for neutron spin echo measurement

Neutron spin echo (NSE) spectroscopy provides unique access to microscopic dynamics, but its application is often constrained by low neutron flux, long acquisition times, and significant noise. We present a Bayesian inference approach based on Gaussian process regression (GPR) to reconstruct high-quality spin echo signals from sparse and noisy data by exploiting correlations in reciprocal space. Benchmarks on synthetic datasets and validation with experimental NSE measurements of dendrimers show that GPR suppresses noise, interpolates missing intensity values, and accommodates irregular observations. The method improves accuracy, shortens acquisition times, and enables high-throughput and real-time studies. Beyond NSE, the framework is broadly applicable to other low signal-to-noise ratio scattering techniques, thereby extending the scope of neutron spectroscopy.

Interplay Between Enteroendocrine Hormone (Leptin) and Adipokines (Ghrelin and Adiponectin) with Gastric Expression of FTO and MC4R Genes

Abstract Obesity is a complex, multifactorial disease influenced by genetic, hormonal, and metabolic factors. The fat mass and obesity-associated (FTO) and melanocortin 4 receptor (MC4R) genes have been implicated in body weight regulation through gut–brain signaling and their interactions with adipokines and enteroendocrine hormones. This study investigated the association between gastric expression of FTO and MC4R genes and circulating levels of leptin, adiponectin, and ghrelin in individuals with and without obesity. We conducted a case–control study including 50 patients with obesity undergoing sleeve gastrectomy and 50 controls undergoing diagnostic endoscopy. Gastric tissue gene expression was assessed by qRT-PCR, and serum hormone levels were quantified using ELISA. Inverse propensity score weighting was used to adjust for age and sex. FTO expression was significantly upregulated in patients with obesity (fold-change: 5.8 vs. 1.0, p  < 0.001), showing a parallel elevation with adiponectin and BMI at the group level. In contrast, MC4R expression was significantly downregulated (fold-change: 0.1 vs. 1.0, p  < 0.001), and positively associated with HOMA-IR and showed a borderline positive trend with fasting blood glucose ( p  = 0.074). Adiponectin levels were paradoxically elevated in the obesity group and correlated with both BMI and HDL. Leptin and ghrelin levels showed no significant group differences. These findings suggest that altered gastric expression of FTO and MC4R may contribute to obesity-related metabolic disturbances through peripheral adipokine pathways. Further investigation into tissue-specific gene–hormone interactions may inform novel therapeutic strategies for obesity.

Phase behavior of active particle-loaded vesicles

We investigate the phase behavior of flexible two-dimensional vesicles loaded with self-avoiding active particles. We construct structural phase diagrams as a function of system density, particle loading, and the degree of activity of the particles inside the vesicle. We identify a range of non-trivial structures reminiscent of those observed in systems of liquid crystals. We examine the stability of these phases with varying particle load and activity, finding that while activity often destabilizes the ordered structures by exciting their soft modes, it can also induce novel ordered configurations absent in the parent passive system.

Real-time construction safety monitoring using a drone based deep hybrid attention model

Chaos in nonequilibrium two-temperature ( <i>T</i> <i>x</i> , <i>T</i> <i>y</i> ) Nosé–Hoover cell models

We revisit a two-temperature Nosé–Hoover wanderer particle embedded in a two-dimensional periodic 2 × 2 cell with four smooth repulsive corners at (x, y) = (±1, ±1) to explore chaos with anisotropic thermostatting. The model employs separate thermostats in the x and y directions, enabling controlled deviations from equilibrium. By integrating the full six-dimensional equations of motion and computing the complete Lyapunov spectrum, we confirm chaos and quantify phase-space contraction from the fully resolved six-dimensional Lyapunov spectrum. The total contraction rate, interpreted as entropy production, increases nonlinearly with the thermostat anisotropy, deviating from the quadratic dependence expected from linear-response theory, Λ ∝ δ2. We analyze two functional forms for the entropy-production rate, Λ(δ) (with δ = 0.5 − Ty): (i) a quadratic-plus-quartic expansion, consistent with linear-response expectations, and (ii) a power law, Λ ∝ δ2.44. While the latter captures the low-driving regime slightly better, the former more accurately describes the strongly driven regime and remains consistent with linear-response theory near equilibrium. An empirical linear relation between dissipation and phase-space dimensionality loss is also identified, Λ ≈ (DKY − 6)/3, where DKY is the approximate Kaplan–Yorke dimension. Momentum statistics show a significant non-Gaussian behavior under strong driving. Despite its dissipative nature, the model remains strictly time-reversible, offering a pedagogically rich example of microscopic reversibility coexisting with macroscopic entropy production.

Ultrafast synthesis of α-aminophosphonates using ternary deep eutectic solvent in water

Unveiling the dynamical genesis of quantum entanglement in linear systems: Internal causality breaking in the reduced subsystem evolution

Utilizing the general theory of open quantum systems to investigate the exact dynamical evolution of simple bilinear systems, we discover a mechanism of the dynamical genesis of quantum entanglement. We focus in detail on the exact quantum evolution dynamics of two photonic modes (or any two bosonic modes) coupled to each other through a linear interaction, as the simplest system of open quantum systems that we have investigated in the past two decades. Such a linear coupling alone fails to produce two-mode entanglement. We also start with an initially separable pure state of the two modes. By solving exactly the quantum equation of motion without relying on the probabilistic interpretation, we find that when the initial state of one mode is different from a coherent state (a minimum uncertainty wave packet with equal variance in the conjugate quadratures that corresponds to a well-defined classically “particle”), the causality in the time-evolution of each mode is internally violated. It also leads to the emergence of quantum entanglement between the two modes. The lack of causality is the nature of statistics. We discover that it is the internal violation of causality in the reduced (subsystem) dynamical evolution that results in the emergence of entanglement and statistic probability in quantum mechanics, even though the dynamical evolution of the whole system completely obeys the deterministic Schrödinger equation. This conclusion is valid for the quantum dynamics of more complicated composite systems. It may provide the fundamental mechanism of the dynamical genesis for both the entanglement and the statistical probability within the deterministic framework of quantum mechanics, which is the longest-standing problem that has not been fully understood since the birth of quantum mechanics.