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Optical pump-terahertz emission probe of ultrafast magnetization dynamics
Understanding spin dynamics on ultrafast timescales offers not only fundamental insights into the coupling of both electrons and phonons with spins but also opportunities for faster and more efficient spintronic devices. However, reliable access to ultrafast spin dynamics in materials and devices under realistic device-operation conditions remains a challenge. Here, we demonstrate a spectroscopic method of optical pump-terahertz (THz) emission (OPTE), which gives direct access to the ultrafast demagnetization and re-magnetization dynamics in a contact-free method under ambient conditions. The observation time window is not limited by the pulse width of THz radiation emitted by the sample. We measure the ultrafast spin dynamics in a laser-excited Fe monolayer. Our measurements disentangle distinct components originating from (i) the ultrafast magnetization quenching that occurs in less than 0.5 ps and (ii) the fast and slow magnetization recoveries that correspond to the spin–lattice coupling and heat diffusion from the sample into the substrate/surroundings, respectively. The OPTE can be a platform to probe and optimize the performance of magneto-optical recording materials and THz emission applications.
Structural basis for pharmacotherapeutic action of triple reuptake inhibitors
Triple excitations in nuclear–electronic orbital coupled cluster theory for multiple quantum protons
Within the nuclear–electronic orbital (NEO) framework, specified nuclei, typically protons, are treated quantum mechanically on the same level as the electrons. This framework allows for nuclear quantum effects, such as anharmonic zero-point energy, to be included in quantum chemical calculations in a computationally efficient manner. NEO coupled cluster (NEO-CC) methods provide a promising strategy for producing accurate ground-state properties of moderately sized molecular systems. Herein, the inclusion of triple excitations in NEO-CC methods is explored for systems with multiple quantum protons. Full and perturbative treatments of electron–electron–proton and electron–proton–proton triple excitations are investigated. The perturbative treatment agrees quantitatively with the full treatment for proton affinity calculations and is much more computationally efficient, especially for systems with multiple quantum protons. The NEO-CCSD(T) method, which includes single, double, and perturbative electron–electron–proton, electron–proton–proton, and electron–electron–electron triple excitations, reproduces experimentally measured proton affinities within experimental uncertainty using a complete basis set extrapolation. Moreover, application of the NEO-CCSD(T) method to protonated water tetramers, with all nine protons treated quantum mechanically, incorporates the essential anharmonic zero-point energy with only a single-point energy calculation. NEO-CC methods offer an accurate and computationally practical approach for inclusion of nuclear quantum effects in molecular systems and may serve as a benchmark for lower-level NEO methods.
Aiolos restricts the generation of antigen-inexperienced, virtual memory CD8+ T cells in mice
Mixed Gaussian and plane wave basis set implementation of the random phase approximation and of <i>σ</i> -functionals within the program package CP2K
The reliability of the random phase approximation (RPA) and of σ-functional methods in conjunction with the mixed Gaussian and plane wave (GPW) basis set scheme as implemented in the CP2K package is investigated. First, based on the results for thermochemical properties of molecules and structural properties of crystalline solids, we establish reliable computational setups for practical calculations. Next, we compare the results obtained with these setups to those from standard GPW basis set approaches. For molecules, the results of RPA and σ-functional calculations within the GPW scheme are slightly worse, though still comparable, to those obtained using the standard Gaussian basis set scheme, provided a large enough orbital basis set is employed in the GPW calculations. Furthermore, the GPW calculations using σ-functionals are clearly more accurate than RPA calculations and even more so than those of conventional Kohn–Sham methods in the prediction of reaction energies and barrier heights for main group chemistry. For crystalline solids, the RPA and σ-functional methods significantly outperform the conventional Perdew–Burke–Ernzerhof (PBE) method in determining lattice constants. However, only the RPA method provides improved results for bulk moduli, while the σ-functional method yields errors comparable to those of the PBE method. A comparison of the results of the plane wave basis set calculations with the projector augmented wave method shows reasonable consistency for lattice constants and bulk moduli.
Visualizing insecticide control of insect TRP channel function and assembly
Effects of trap sites on magnetic-field dependent electric conductance and recombination of carriers photogenerated in a dye-doped organic semiconductor film device
Photogenerated radical ion pairs are important intermediates that govern the optoelectronic and magnetic responses of organic materials. We have succeeded in observing a singlet-born radical pair with a microsecond-order lifetime in a photoelectric device comprising a perylenediimide-doped poly(N-vinylcarbazole) film at room temperature. The simultaneously detected transient optical absorption signal due to the electron and photocurrent signal due to the hole are enhanced by an applied magnetic field of 250 mT, which is explained by the quantum spin dynamics of the radical pair. Detailed analysis of the magnetic field effect and its temperature dependence has revealed that the photogenerated holes that comprise the radical pair are captured in either a shallow trap site of a few meV depth or a deep trap site of 100–200 meV depth, from which detrapping-limited (∼100 ns) and tunneling recombination (a few microseconds) occur, respectively. In contrast to the nearly temperature-independent recombination dynamics, the hole drift mobility exhibits large activation energies of over 100 meV because the hole transport in the micrometer range is limited by detrapping from the deep trap site. The present study demonstrates the importance of trap sites in disordered materials, which can be utilized as reservoirs for long-lived radical pairs.
The mechanisms underlying the enhanced high-temperature properties of GRX-810
Abstract The demand for metal alloys that can perform at extreme temperatures above 1100 °C while remaining manufacturable has sparked renewed interest in printable oxide dispersion strengthened (ODS) alloys. Recently, NASA developed an ODS alloy designed for additive manufacturing, known as GRX-810, which has demonstrated exceptional tensile and creep performance at temperatures of 1093 °C and higher. In the present study, tensile tests of GRX-810 are conducted up to 1316 °C and creep tests are performed in both the horizontal and vertical orientations, relative to the build direction. Thermal cycling is executed at 1100 °C, 1200 °C, and 1300 °C in air. The oxidation behavior of GRX-810 is compared to that of alumina forming single crystal Ni-base superalloys and chromia-forming wrought alloys such as superalloys 718 and 625. High resolution atomic-scale characterization and atomistic modeling are employed to explain the exceptional high temperature properties observed in GRX-810, particularly in relation to the unique, finer trigonal yttrium oxides produced during the additive manufacturing process.
Influence of dipolar solvent fluctuations on polyelectrolyte thermodynamics and complex coacervation
We present a self-consistent polyelectrolyte field theory that reveals the impact of solvent polarity and polymer semiflexibility on polyelectrolyte solution thermodynamic behavior. Our approach incorporates a microscopic treatment of the solvent dipolar field and focuses on the importance of the charge separation distance in the dipole solvent. Consequently, this leads to an inhomogeneous dielectric medium at microscopic length scales and a significant free-energy contribution that manifests as the insolubility of uncharged species in a polar solvent. We then add the Born solvation energies of each charged species to account for their inherent solubility. Using this updated theory, which incorporates quadratic-order concentration fluctuation corrections, we generate phase diagrams for oppositely charged polyelectrolyte solutions that display phase re-entrant behavior for weakly charged polyelectrolytes and capture phase behavior consistent with recent experimental findings.
The microRNA miR-71 suppresses maladaptive UPRmt signaling through both cell-autonomous and cell-non-autonomous mechanisms
Abstract Mitochondria play a central role in metabolism and biosynthesis, but function also as platforms that perceive and communicate environmental and physiological stressors to the nucleus and distal tissues. Systemic mitochondrial signaling is thought to synchronize and amplify stress responses throughout the whole body, but during severe or chronic damage, overactivation of mitochondrial stress pathways may be maladaptive and exacerbate aging and metabolic disorders. Here we uncover a protective micro(mi)RNA response to mtDNA damage in Caenorhabditis elegans that prolongs tissue health and function by interfering with mitochondrial stress signaling. Acting within muscle cells, we show that the miRNA miR-71 is induced during severe mitochondrial damage by the combined activities of DAF-16, HIF-1, and ATFS-1, where it restores sarcomere structure and animal locomotion by directly suppressing the inordinate activation of DVE-1, a key regulator of the mitochondrial unfolded protein response (UPR mt ). Indirectly, miR-71 also reduces the levels of multiple neuro- and insulin-like peptides and their secretion machinery, resulting in decreased cell-non-autonomous signaling of mitochondrial stress from muscle to glia cells. miR-71 therefore beneficially coordinates the suppression of both local and systemic mitochondrial stress pathways during severe organelle dysfunction. These findings open the possibility that metabolic disorders could be ameliorated by limiting the overactivation of mitochondrial stress responses through targeted small RNAs.
A data-driven and quantum chemistry-anchored framework for modeling and classifying carbon–lithium bonding in organolithium aggregates
We present a quantum chemistry-based, data-driven framework for the automated classification of carbon–lithium bonding motifs in archetypal organolithium aggregates. Starting from ab initio potential energy surfaces-guided sampling, we constructed a chemically complete dataset of 81 optimized gas-phase aggregates of methyllithium, t-butyllithium, and phenyllithium (600 C–Li bonds in total) spanning all relevant nuclearities and bonding modes. Twenty geometric, electronic, and topological descriptors obtained from quantum theory of atoms in molecules and Electron Localization Function (ELF) analyses were evaluated via correlation clustering, yielding a minimal, non-redundant, chemically meaningful set dominated by the ELF basin electron population and key bond-path metrics. This reduced descriptor set was used to train two complementary supervised models—a multi-task fully connected neural network and a bootstrap-aggregated decision tree—achieving accuracies of 84% (nucleophile type), 89% (aggregation state), and 84% (bond type) on validation data. Both methods consistently identified ELF-derived descriptors as the most discriminative, enabling physically grounded separation of bonding regimes (2c–2e, multi-center, non-classical, π–Li) and providing an interpretable, transferable platform for high-throughput bonding analysis in organometallic chemistry.
Robust fast-switching black electrochromic windows based on solution-processed n-doped transparent organic conductor
easyPARM v4.00: A Python-based tool for the automated parameterization of metalloproteins and metal-organic polyhedra with multiple metal centers
Force-field parameters for classical molecular dynamics simulations of metal centers are often derived from electronic structure calculations due to the inexistence of transferable libraries. Metalloproteins and metal-organic polyhedrons systems add more layers of complexity with respect to molecular transition metal complexes due to the usual presence of multiple metal cores and the coordination with amino acids of the protein and/or non-standard structures, forcing user intervention and making the parameterization process very tedious, time-demanding, and prone to errors. This work presents easyPARM v4.00, a Python-based tool that allows the automated parameterization of these (multi)metallic systems, strongly minimizing human intervention and computational cost. Additional implementations like compatibility with the GAMESS-US software and the non-interactive mode are explained in detail, whereas the quality of the obtained parameters is systematically validated against reference data (including density functional theory molecular dynamics), fully demonstrating that the proposed procedure is not only streamlined but also reliable and versatile. The code is distributed as open source and free of charge on GitHub at https://github.com/Abdelazim-Abdelgawwad/easyPARM.git.
Single-array measurements reveal non-uniform, mosaic-like chemosensory arrays in bacteria
Replicated liquid theory in 1 + <i>∞</i> dimensions
We develop a replicated liquid theory for structural glasses that exhibit spatial variation of physical quantities along one axis, say z-axis. The theory becomes exact with an infinite transverse dimension d − 1 → ∞. It provides an exact free-energy functional with a space-dependent glass order parameter Δab(z). As a first application of the scheme, we study diverging lengths associated with dynamic/static glass transitions of hard spheres with/without a confining cavity. The exponents agree with those obtained in previous studies on related mean-field models. Moreover, it predicts a non-trivial spatial profile of the glass order parameter Δab(z) within the cavity, which exhibits a scaling feature approaching the dynamical glass transition.
Complex genetic effects linked to plasma protein abundance in the UK Biobank
Abstract Understanding genetic associations of proteins is important for studying the molecular effect of genetic variation. A key component of this is to understand the role of complex genetic effects such as dominance and epistasis that are associated with plasma proteins. Therefore, we develop EIR-auto-GP, a deep learning-based approach, to identify complex effects that are associated with protein quantitative trait loci (pQTLs). Applying this method to the UK Biobank proteomics cohort of 48,594 individuals, we identify 123 proteins that are correlated with non-linear covariates and 15 with genetic dominance and epistasis. We uncover a novel interaction between the ABO and FUT3 loci and demonstrate dominance effects of the ABO locus on plasma levels of pathogen recognition receptors CD209 and CLEC4M. Furthermore, we replicate these findings and the methodology across Olink and mass spectrometry-based cohorts. Our approach presents a systematic, large-scale attempt to identify complex effects of plasma protein levels.
The effect of selective monodoping and co-doping at A/B-site on the ferroelectricity and piezoelectricity in KNbO3
Ion doping is one of the most effective strategies to tailor the piezoelectric properties of alkali niobate ceramics. However, its underlying mechanisms remain insufficiently understood. In this work, the structural, ferroelectric, and piezoelectric properties of the selected A- or B-site monodoping and codoping in orthorhombic KNbO3(KN) are studied by density-functional calculations. A-site substitutions include alkali (Li, Na, Rb, Cs), alkaline-earth (Mg, Ca, Sr, Ba), and Bi ions, while B-site doping involves Nb replacement with isovalent (V, Ta, P, As), group IVB (Ti, Zr, Hf), and Bi atoms. Two co-doping combinations, (Na, Sb) and (Ba, Zr), are also studied. The orientational averaged shear, transverse, and longitudinal piezoelectric coefficients d̄15*, d̄31*, and d̄33* of the A/B-site monodoping and codoping in KN piezoceramics are calculated from the results of single crystals. The calculated values clearly indicate that the substitution of Na, Cs, and Ca at the A-site can result in higher piezoelectricity, while the incorporation of V, Ta, Ti, Bi, and Sb to substitute Nb atoms induces better piezoelectric performance. Moreover, the codoping technique of (Na, Sb)- and (Ba, Zr)-doped KN crystals significantly enhances the piezoelectricity compared with the pure KN and those monodoping cases. These findings demonstrate that ion doping plays a critical role in flattening the energy landscape and enhancing the piezoelectric performance of perovskite ferroelectrics.
New SAR11 isolate genomes and global marine metagenomes resolve ecologically relevant units within the Pelagibacterales
Hybrid explicit-droplet/implicit solvation model to accelerate constant-potential molecular dynamics simulations
Using hybrid solvation model has become an important way to simulate the dynamics of electrochemical solid–liquid interfaces under realistic solvation and potential. However, since it typically relies on fully covering explicit solvent layers, it suffers from high computational cost and the dissolution of solvent molecules into the implicit solvent. To address these challenges, we present a hybrid explicit-droplet/implicit solvation model implemented based on VASPsol++, which enables efficient constant-potential molecular dynamics simulations around local reactive sites. This model employs an algorithm to exclude implicit solvent within the droplet and a velocity-reflection algorithm that prevents explicit solvent molecules from dissolving into the implicit solvent. It features both radius- and density-constant implementations and integrates a continuous cavity. Validated with established water-layer models, the droplet approach reliably replicates key interfacial properties, such as electron-count fluctuations and free-energy barriers from enhanced sampling calculations, in exemplar systems including Co–N–C motifs and MoS2 edges. Notably, this model accelerates barrier-calculation speed by 2–4 times, depending on slab size and specific settings, while providing reliable results. This study offers a new tool through which simulating the electrochemical interface using constant-potential molecular dynamics is significantly accelerated and more broadly accessible.