Browse Articles

Refined approach to cellularization: Going from Heller’s thawed Gaussian approximation to Herman–Kluk’s initial value representation

We present a refined cellularization (Filinov filtering) scheme for the semiclassical Herman–Kluk propagator, which employs the inverse Weierstrass transform and optimal scaling of the cell size with the number of cells and was previously used only in the context of the dephasing representation. In the new methodology, the sampling density for the cell centers correlates with the cell size, allowing for an effective sampling of the phase space covered by the initial state of the system. The main advantage of the presented approach is that, unlike the standard cellularization, it converges to the original Herman–Kluk result in the limit of an infinite number of trajectories and to the thawed Gaussian approximation when a single trajectory is used. We illustrate the performance of the refined cellularization scheme by calculating autocorrelation functions and spectra of both integrable and chaotic model systems.

The simulation of judgment in LLMs

Large Language Models (LLMs) are increasingly embedded in evaluative processes, from information filtering to assessing and addressing knowledge gaps through explanation and credibility judgments. This raises the need to examine how such evaluations are built, what assumptions they rely on, and how their strategies diverge from those of humans. We benchmark six LLMs against expert ratings—NewsGuard and Media Bias/Fact Check—and against human judgments collected through a controlled experiment. We use news domains purely as a controlled benchmark for evaluative tasks, focusing on the underlying mechanisms rather than on news classification per se. To enable direct comparison, we implement a structured agentic framework in which both models and nonexpert participants follow the same evaluation procedure: selecting criteria, retrieving content, and producing justifications. Despite output alignment, our findings show consistent differences in the observable criteria guiding model evaluations, suggesting that lexical associations and statistical priors could influence evaluations in ways that differ from contextual reasoning. This reliance is associated with systematic effects: political asymmetries and a tendency to confuse linguistic form with epistemic reliability—a dynamic we term epistemia, the illusion of knowledge that emerges when surface plausibility replaces verification. Indeed, delegating judgment to such systems may affect the heuristics underlying evaluative processes, suggesting a shift from normative reasoning toward pattern-based approximation and raising open questions about the role of LLMs in evaluative processes.

Chromatin looping-based CRISPR screen identifies TLK2 as chromatin loop formation regulator in cancer stemness plasticity

Bioinformatic analysis of rare endothelial protein C receptor missense variants associated with coagulation and thrombophilia risk

Translational dynamics of diatomic molecule in magnetic quadrupole trap

We study the translational motions of homonuclear diatomic molecules prepared in their 3Σ electronic states, deeply bound vibrational states, and rotational states of well-defined parity. The trapping potential arises due to the interaction of the total spin of electrons and orbital angular momentum of nuclei with the trap’s quadrupole magnetic field. The translational motion of a molecule is treated classically. We examine the Hamilton equations that govern the center-of-mass dynamics both numerically and analytically. Using data of a hydrogen molecule at the ground vibrational state, we present global dynamics using the Poincaré section method and various types of trajectories: periodic, quasiperiodic, and chaotic. We prove that the Hamiltonian system governing this motion is non-integrable. The particle’s orbits are confined to a bound region of space that grows with energy, but for small energies (<1.8 K), the motion is restricted to a processing chamber (a few centimeters). Solutions of equations of motion occurring on the symmetry axis and the horizontal plane are expressed in terms of Jacobi elliptic functions.

Sperm and offspring production in a nonobstructive azoospermia mouse model via testicular mRNA delivery using lipid nanoparticles

Microsurgical testicular sperm extraction (microTESE) with intracytoplasmic sperm injection (ICSI) represents the current standard treatment for nonobstructive azoospermia (NOA). However, cures remain unavailable for NOA patients lacking retrievable haploid cells. mRNA supplementation could be a potential treatment for genetic defects leading to impaired spermatogenesis. Lipid nanoparticles (LNPs) have emerged as mRNA delivery vehicles with minimal risk of genome integration; however, their ability to selectively deliver mRNA to specific cell types remains limited. To overcome this, microRNA (miRNA) target sequences were incorporated into mRNA constructs to restrict expression specifically to germ cells. Using pyruvate dehydrogenase E1 subunit alpha 2 (PDHA2) knockout mice as an NOA model with meiotic arrest, we demonstrate that LNP-mediated delivery of Pdha2 mRNA enables the resumption and completion of meiosis, restores sperm production, and facilitates the generation of healthy fertile offspring via ICSI. Whole-genome sequencing of the offspring confirmed the absence of large-scale genomic abnormalities. Our results provide proof of concept for a safe and effective chemically synthesized LNP-based mRNA therapy with miRNA-regulated germ cell specificity, offering a promising therapeutic approach to treating male infertility caused by spermatogenesis arrest.

APOA1 binding protein promotes lymphatic cell fate and lymphangiogenesis by relieving caveolae-mediated inhibition of VEGFR3 signaling

Biological evaluation and molecular Docking studies of the prepared chalcone derivatives as potential anti-Alzheimer agents

Molecular axis distribution moments in ultrafast transient absorption spectroscopy: A path toward ultrafast quantum state tomography

In ultrafast time-resolved experiments with gas phase molecules, the alignment of the molecular axis relative to the polarization of the interacting laser pulses plays a crucial role in determining the dynamics following this light–matter interaction. The molecular axis distribution is influenced by the interacting pulses and is intrinsically linked to the electronic coherences of the excited molecules. However, in typical theoretical calculations of such interactions, the signal is either calculated for a single molecule in the molecular frame or averaged over all possible molecular orientations to compare with the experiment. Such averaging removes information about anisotropy in the molecular-axis distribution, even though anisotropic contributions can play a significant role in the measured experimental signal. Here, we calculate the laboratory frame transient electronic first-order polarization [P(1)] spectra in terms of separated molecular frame and laboratory frame quantities. The laboratory frame polarizations are compared with orientation-averaged quantum master equation calculations, demonstrating that orientation-averaging captures only the isotropic contributions. We show that our formalism also allows us to evaluate the anisotropic contributions to the spectrum. Finally, we discuss the application of this approach to achieve ultrafast quantum state tomography using transient absorption spectroscopy and field observables in nonlinear spectroscopy.

High-magnetic-field phases in U _1-x Th _x Te ₂

At temperatures T much lower than its superconducting critical temperature T c = 2.1 K, the heavy fermion superconductor UTe 2 has a unique phase diagram of magnetic field H vs. φ and θ, angles H is tilted from the b -axis toward the a - and c -axes, respectively, of its orthorhombic unit cell. The phase diagram contains three distinct superconducting phases: SC 1 in which φ and θ extend from 0 to 90° and H ≤ ~15 T; SC 2 for φ ≤ ~7°, θ ≤ ~4° and ~15 T ≤ H ≤ H m = ~35 T, the onset of the magnetic field polarized (FP) phase, and SC FP which resides entirely within the FP phase in a pocket of superconductivity extending from θ ≈ 20° to 40° and from ~40 T to above 60 T. We studied the evolution of the H vs. θ phase diagram for Th concentrations 0.005 ≤ x ≤ 0.047 in the U 1-x Th x Te 2 system at ~0.6 K. Within this range of x values, SC 1 extends over 0 ≤ θ ≤ 90° and H ≤ ~10 T for x = 0.047, while SC 2 is suppressed. The SC FP and FP phases are unaffected to x = 0.02 but are completely suppressed in the region x = 0.025 to 0.047 where the residual resistance ratio RRR ~3 indicates a significant amount of disorder. These results complement recent studies of nonsuperconducting disordered UTe 2 single crystals in which the SC 1 and SC 2 phases are absent, but the FP and so-called “orphan” SC FP phases are retained.

Boosting a practical lithium carbon dioxide battery through a decoupled electrolyte

Diversity of oxidative stress and senescence phenotypes induced by chemotherapeutic agents in HUVECs

Formation of hexagonal binary crystals in additive hard disk mixtures

The hard disk model is a foundational system for understanding two-dimensional phase behavior. Its extension to binary mixtures introduces additional structural complexity and kinetic constraints that hinder the formation of ordered phases. Although geometric constructions predict a variety of binary crystals at high densities, these phases often fail to self-assemble in simulations due to slow dynamics and competing phase separation. Here, we investigate the spontaneous formation of the H2 hexagonal binary hard disk crystal in additive mixtures using event-driven molecular dynamics. We show that crystallization is highly sensitive to thermodynamic conditions, requires long equilibration, and is facilitated by particle swap moves. Despite its high packing fraction, the H2 crystal forms spontaneously at equimolar composition and near-ideal size ratio but is kinetically hindered at intermediate densities by the formation of competing one-component hexagonal phases. Our results identify the conditions under which H2 binary crystals spontaneously form and show that their emergence can proceed through non-classical nucleation pathways involving metastable intermediates. These findings offer new insights into entropy-driven self-assembly in two-dimensional mixtures and inform strategies for realizing complex order in colloidal and granular materials.

Medicine on the menu: When illness informs appetite

Integrated silicon nitride devices via inverse design

Obesity trends and early-life risk factors in preschool children in Northwest China from 2012 to 2024

A single-GPU implementation of first-principles molecular dynamics

We present a single-Graphics Processing Unit (GPU) implementation of First-Principles Molecular Dynamics (FPMD) using plane wave basis functions and pseudopotentials, for the NVIDIA CUDA platform. We discuss various design choices made to exploit the high memory bandwidth available on a GPU while minimizing host–device data transfers. Applications to FPMD simulations of superionic NH3, liquid water, defects in SiC and MgO, and various systems including up to 512 atoms and 4096 electrons are demonstrated on an NVIDIA A100 GPU and an NVIDIA Grace-Hopper GH200 platform. Performance benchmarks show a significant speedup compared to other GPU-enhanced implementations, enabling the efficient use of computational resources. Applications to ensemble FPMD simulations of free energy barriers of a solvated molecule and residual stress in liquid water are also presented.

Guardians at the border: Peritumoral macrophages fight breast cancer

Solar-hybrid biocatalyst for methane hydroxylation to methanol

The effect of low Al concentration on the electronic structure and thermoelectric properties of AlxGa1−xN/GaN heterojunctions

Abstract The effect of low Al concentrations on the electronic structure and thermoelectric properties of AlxGa1−xN/GaN (x = 0.1250, 0.1875, 0.2500, and 0.3125) heterojunctions was investigated using density functional theory and Boltzmann transport theory. Compared to AlxGa1−xN/GaN heterojunctions with different Al concentrations, it was found that: (1) The bandgap increases and the density of states (DOS) decreases near the Fermi level as the Al concentration increases in AlxGa1−xN/GaN heterojunctions. (2) The Seebeck coefficient of the Al0.25Ga0.75N/GaN heterojunction reaches 1850.20 μV/K at 300 K. (3) For n-type samples, the increase of Al concentration leads to higher conductivity in AlxGa1−xN/GaN heterojunctions. (4) Power factor (PF) decreases with increasing Al concentration in AlxGa1−xN/GaN heterojunctions. At the lowest Al concentration, the power factor of the Al0.125Ga0.875N/GaN heterojunction reaches 1.48 × 1011W/(m·K2·s) at 900K. (5) The maximum electronic thermoelectric quality factor (ZTe) of the Al0.25Ga0.75N/GaN heterojunction reaches 1.41, and at the same temperature, the n-type AlxGa1−xN/GaN heterojunctions exhibit significantly higher performance than the p-type. The results are useful for exploring the thermoelectric properties of GaN-based heterojunctions and improving the performance of thermoelectric devices.