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Your lab pollutes: here’s how to stop it

Quantum electrodynamic corrections for molecules: Vacuum polarization and electron self-energy in a two-component relativistic framework

Vacuum polarization (VP) and electron self-energy (SE) are implemented and evaluated as quantum electrodynamic (QED) corrections in a (quasi-relativistic) two-component zeroth order regular approximation (ZORA) framework. For VP, the Uehling potential is considered, and for SE, the effective potentials proposed by Flambaum and Ginges as well as the one proposed by Pyykkö and Zhao. QED contributions to ionization energies of various atoms and group 2 monofluorides, group 1 and 11 valence orbital energies, 2P1/2 ← 2S1/2 and 2P3/2 ← 2S1/2 transition energies of Li-, Na-, and Cu-like ions of nuclear charge Z = 10, 20, …, 90 as well as Π1/2 ← Σ1/2 and Π3/2 ← Σ1/2 transition energies of BaF and RaF are presented. Furthermore, perturbative and self-consistent treatments of QED corrections are compared for Kohn–Sham orbital energies of gold. It is demonstrated that QED corrections can be obtained in a two-component ZORA framework efficiently and in excellent agreement with corresponding four-component results.

Meta-analysis of heat-induced changes in cardiac function from over 400 laboratory-based heat exposure studies

Enhancing performance of 0.15PIN-0.60PMN-0.25PT single crystal for (001)-oriented via alternating current poling and (110)-oriented via pulse poling

In this work, the (001)- and (110)-oriented 0.15Pb(In1/2Pb1/2)O3-0.60Pb(Mg1/3Nb2/3)-0.25PbTiO3 (0.15PIN-0.60PMN-0.25PT) single crystal plates were investigated under different poling methods, i.e., direct current poling (DCP), alternating current poling (ACP), and pulse poling (PP) methods. The (110)-oriented sample has a larger remnant polarization and coercive field than those of the (001)-oriented sample. Dielectric performance measurement and unipolar electric field-induced strain disclose successive ferroelectric phase transitions, in which the largest maximum strain and converse piezoelectric constant d33* are induced near the phase transition temperatures. The optimized poling conditions present a slight difference in crystal orientation and poling methods. For the (001) orientation, the ACP sample presents the highest piezoelectric constant d33 and electromechanical coupling coefficient kt of 1890 pC/N and 0.572, elevating 32.7% and 4.7%, respectively, as compared to the DCP sample. For the (110) orientation, the PP sample presents d33 of 1238 pC/N and kt of 0.498, enhancing 18.1% and 2.7%, respectively, by contrast with the DCP sample. The domain configuration of both the ACP (001)-oriented and PP (110)-oriented crystal plates presents a higher domain wall density as compared to the samples poled by the other two methods, which is considered a substantial factor for the improvement of piezoelectric performance.

Enhancing reaction efficiency in photochemical organic synthesis by controlling the dynamic effects of excitons

Donor–acceptor (D–A) molecules are key motifs in electron transfer processes. Recently, significant progress has been made in the development of organic synthetic reactions that utilize D–A molecules as photoredox catalysts. In these electron-transfer reactions, preventing undesired back-electron transfer and achieving efficient conversion is essential. In this Perspective, we introduce two examples in which the dynamic effects of excitons derived from catalyst molecules are controlled through precise molecular design.

Potentially causal associations between placental DNA methylation and schizophrenia and other neuropsychiatric disorders

Molecular aspect ratio effect on axial thermal transport in solution-spun carbon nanotube fibers

Neat, densely packed, and highly aligned carbon nanotube fibers (CNTFs) have appealing room-temperature axial thermal conductivity (k) and thermal diffusivity (α) for applications in lightweight heat spreading, flexible thermal connections, and thermoelectric active cooling. Although CNTFs are regularly produced from different input carbon nanotubes (CNTs), prior work has not quantified how the CNT molecular aspect ratio r (i.e., molecular length-to-diameter ratio) influences k and α in well-aligned, packed CNTFs. Here, we perform self-heated steady-state and three-omega thermal measurements at room temperature on CNTF suspended in vacuum. Our results show that k increases from 150 to 380W/mK for viscosity-averaged molecular aspect ratios increasing from r=960 to 5600 and nanotube diameters of ∼2 nm, which we attribute to the effects of thermal resistances between CNT bundles. CNTFs made with varying volume fraction ϕ of constituent high-r and low-r CNT have properties that fall within or below the typical macroscopic rule-of-mixtures bounds. The thermal diffusivity α scales with k, leading to a sample-averaged volumetric heat capacity of 1.5±0.3MJ/m3K. This work's findings that fibers made from longer CNT have larger k and α at room temperature motivate further investigation into thermal transport in solution-spun CNTF.

Accelerating polymer self-consistent field simulation and inverse DSA-lithography with deep neural networks

Self-consistent field theory (SCFT) is a powerful polymer field-theoretic simulation tool that plays a crucial role in the study of block copolymer (BCP) self-assembly. However, the computational cost of implementing SCFT simulations is comparatively high, particularly in computationally demanding applications where repeated forward simulations are needed. Herein, we propose a deep learning-based method to accelerate the SCFT simulations. By directly mapping early SCFT results to equilibrium structures using a deep neural network (DNN), this method bypasses most of the time-consuming SCFT iterations, significantly reducing the simulation time. We first applied this method to two- and three-dimensional large-cell bulk system simulations. Both results demonstrate that a DNN can be trained to predict equilibrium states based on early iteration outputs accurately. The number of early SCFT iterations can be tailored to optimize the trade-off between computational speed and predictive accuracy. The effect of training set size on DNN performance was also examined, offering guidance on minimizing dataset generation costs. Furthermore, we applied this method to the more computationally demanding inverse directed self-assembly-lithography problem. A covariance matrix adaptation evolution strategy-based inverse design method was proposed. By replacing the forward simulation model in this method with a trained DNN, we were able to determine the guiding template shapes that direct the BCP to self-assemble into the target structure with certain constraints, eliminating the need for any SCFT simulations. This improved the inverse design efficiency by a factor of 100, and the computational cost for training the network can be easily averaged out over repeated tasks.

Author Correction: A single-photon emitter coupled to a phononic-crystal resonator in the resolved-sideband regime

Realizing permutation gates with phi-bits: Acoustic quantum analogue computing

We present both the theoretical framework and experimental implementation of permutation gates using logical phi-bits, classical acoustic analogs of qubits. Logical phi-bits are nonlinear acoustic modes supported by externally driven acoustic metamaterials. Using a tensor product of modified Bloch sphere representations, we realize all possible two logical phi-bit permutations including SWAP and C-NOT. We also illustrate the scalability of a permutation for any number of logical phi-bits. Experimental demonstrations of these permutations require a single physical action on the driving conditions of the acoustic metamaterial. All logical phi-bits exist in the same physical system. We compare the phi-bit system with its quantum counterpart using Qiskit simulations, which illustrate the complexity of realizing these permutations in a quantum context.

Structural, electronic, and ferroelectric transitions in van der Waals ferroelectric CuInP2Se6 under high temperature and high pressure

In this work, the high-temperature and high-pressure ferroelectric, structural, and electrical transport properties for CuInP2Se6 upon compression and decompression under different hydrostatic environments were comprehensively studied via Raman spectroscopy, electrical conductivity, and high-resolution transmission electron microscopy observations. Upon non-hydrostatic pressurization, CuInP2Se6 experienced two successive phase transitions at 5.4 and 14.1 GPa originating from the rapid compression of van der Waals gaps and the local structure variation of Se–P–Se bonds, followed by a metallization at 25.1 GPa. Furthermore, a ∼2.0 GPa pressure hysteresis was detected for the emergence of electronic transformation in CuInP2Se6 under hydrostatic conditions owing to the influence of hydrostaticity. Upon decompression, the phase transition of CuInP2Se6 was demonstrated to be reversible with considerable pressure hysteresis under different hydrostatic environments. In addition, the positive sinusoidal voltage-dependent electrical current relations with the nonlinearity factors of ∼1.0 manifested the Ohmic response of CuInP2Se6 under high pressure conditions. Meantime, the disappearance of the P1 Raman peak and the discontinuities in Raman shifts and full width at half-maximums offered robust evidence on the occurrence of ferroelectric crossover in CuInP2Se6. It is the first time that the phase boundary from the mixed antiferroelectric and ferroelectric (FE) orderings into the FE state of CuInP2Se6 is well established [i.e., TC (K) = 165.5 P (GPa) + 292.1] under the conditions of 298–873 K and 0.4–40.3 GPa. Our findings shed light on the ferroelectricity, crystalline structure, and electrical configuration of CuInP2Se6 under extreme conditions, which is of paramount significance to the fundamental research and potential applications for other metallic thio(seleno)phosphates.

Anion-mediated approach to overcome oxidation in ether electrolytes for high-voltage sodium-ion batteries

Tailoring additive manufacturing to optimize dynamic properties in 316L stainless steel

With the advent of additive manufacturing, manipulation of typical microstructural elements such as grain size, texture, and defect densities is now possible at a faster time scale. While the processing–structure–property relationship in additive manufactured metals has been well studied over the past decade, little work has been done in understanding how this process affects the dynamic behavior of materials. We postulate that additive manufacturing can be used to alter the material microstructure and used to enhance its dynamic strength. In this work, 316L stainless steel (SS) was manufactured via selected laser melting and its microstructure was altered through changing build parameters like laser power, speed, and hatch spacing systematically. These samples were then subjected to spall recovery experiments to measure the spall strength and quantify the amount of damage as a function of build parameters. By mapping the spall strength as a function of build parameters, this work demonstrated that indeed additive manufacturing can be used to tailor the spall strength of 316L SS. This work also determined the optimum build parameters (laser power=195W; scanning speed=1083mm/s; hatch spacing=0.09mm; layer thickness=0.02mm) to obtain the highest spall strength and the least amount of total damage in 316L SS. Microstructural characterization of the pre- and post-mortem samples revealed that increased grain average misorientation and textural index were the main driving force behind this higher spall strength. This work aims to enhance microstructural engineering techniques to design materials with greater resistance to dynamic shock loading.

Dye–quencher pair screening for efficient photo-CIDNP: The role of molecular diffusion

Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging are well-established techniques to acquire diverse molecular information, while their potential applications remain limited due to low sensitivity. Photochemically induced dynamic nuclear polarization (photo-CIDNP) is one of the promising methods to solve this issue, and numerous studies have been conducted to understand its physical mechanism using a particular combination of a dye and a quencher of interest. However, the research across multiple dye–quencher combinations remains largely unexplored. Here, we explore plenty of dye–quencher combinations and reveal that not only the electron transfer process but also the optimal value of the g-value difference (Δg), considerably affected by the escape process of a radical pair, plays a key role in maximizing the enhancement of the NMR signal by photo-CIDNP. The combinations of 115 quenchers with several dyes were experimentally investigated, and 36 photo-CIDNP active quenchers were revealed. Exploration of many different dye–quencher combinations with four dyes revealed that molecular diffusion significantly affects the Δg dependence of photo-CIDNP enhancement of each dye. These findings provide important insights into pioneering new dye–quencher combinations suitable for biological and medical applications.

Long read sequencing enhances pathogenic and novel variation discovery in patients with rare diseases

Correlation between ferroelectric domain size and grain size in ferroelectric ceramics: A phase-field study

The properties of ferroelectric ceramics depend on their grain/domain size heavily and former experiments find that their domain size monotonously increases with grain size increasing and the slope of the increase is drastically different at small and large grain sizes. However, a theoretical understanding of the relationship between the domain and grain size is still lacking. In this work, the domain structure of ferroelectric ceramics at different grain sizes is investigated by a phase-field model. Consistent with experiments, it is found that the domain size increases sharply with grain size increasing at small grain sizes and then slowly at larger grain sizes. Analysis shows that at small grain sizes, the increase is sharp because the electrostatic energy leads to the formation of a vortex-like structure with four domains in each grain forcing the domain size to approximately equal to half of the grain size as a result of the strong geometric constraint. At large grain sizes with much weaker geometric constraints, the electrostatic energy can be minimized by forming more than four domains which reduces the slope. In addition, the elastic energy contributes to a further reduction of the slope at large grain sizes. The dielectric permittivity at different grain sizes is calculated and it is found that the permittivity first increases and then decreases with grain size decreasing. This work provides a theoretical understanding of the relationship between the domain and grain size of ferroelectric ceramics and could shed light on the designing of high-performance ferroelectric ceramics.

Effect of intermolecular interactions and elastic frustration on the dynamical properties of the isothermal relaxation of 1D spin crossover chains

We consider an open one-dimensional spin-crossover chain, in which each site can be in either a low spin (LS) or a high spin (HS) state. The sites interact elastically through nearest neighbor (nn) and next-nearest neighbor (nnn) springs with local equilibrium distances depending on the spin states. The system’s Hamiltonian is solved numerically using the Monte Carlo method, applied on both spin states and atomic displacements. This study focuses on the investigations of the isothermal relaxation of a photoinduced HS metastable chain, by analyzing the interplay between the electronic and structural properties along this process. The obtained results indicate that the nucleation and growth mechanisms of LS domains during relaxation are significantly influenced by the amplitude of the intermolecular interactions. Thus, increasing the latter reduces the number of HS/LS clusters due to the high cost of stored elastic energy at HS/LS interfaces. In the second part, we inject an elastic frustration between the equilibrium nn and nnn bond lengths, resulting in the emergence of two distinct relaxation regimes, which depend on the frustration rate, ξ. A detailed analysis of the effect of ξ on the isothermal HS to LS relaxation reveals the stabilization of rich intermediate self-organized electronic structures with long lifetime along this process. Thus, these results clearly demonstrate that the shape of the relaxation curves transforms from a continuous to a two-step behavior, which is reminiscent of the thermal dependence of the order parameters of such models in equilibrium thermodynamics.

FoxO3 controls cardiomyocyte proliferation and heart regeneration by regulating Sfrp2 expression in postnatal mice

Multi-contrast benchmarking of edge illumination Monte Carlo simulations using virtual gratings

In recent years, the complementary nature of multi-contrast imaging has increased the popularity of x-ray phase contrast imaging, including edge illumination. However, edge illumination system optimization most often relies on phase and transmission contrast only, without considering dark field contrast. Computer simulations are a widespread approach to design and optimize imaging systems, including the benchmarking of simulation results, i.e., the comparison to a reference value. Providing such a reference is, however, particularly challenging for the dark field signal. In this work, we present a practical method to directly estimate transmission, refraction, and dark field contrast reference values from simulated x-ray trajectories in Monte Carlo simulations. This allows an immediate comparison of the retrieved simulated contrasts to their respective references. We show how the generated reference values can be used effectively for benchmarking simulation results and discuss other potential applications of the presented approach.

Action-based two-dimensional infrared spectroscopy on the horizon

Time domain two-dimensional infrared (2DIR) spectroscopy extends the capabilities of traditional infrared spectroscopy by revealing information on vibrational modes’ anharmonicities, couplings, and energy transfer processes, making it a powerful tool for studying fast dynamic processes. Recent advancements in mid-IR laser technology and detection methods have significantly improved the resolution and acquisition rate of 2DIR spectroscopy. Despite these exciting developments, 2DIR spectroscopy remains limited by Abbe’s diffraction limit, which restricts its spatial resolution. Aimed to address this challenge, the integration of action-based detection methods, notably the atomic force microscope (AFM)-based photothermal detection, offers a promising solution. AFM-2DIR spectroscopy combines the high spatial resolution of AFM with the richness of molecular insights of 2DIR, allowing nanoscale analysis of heterogeneous samples. This new type of technique would open avenues for investigating complex molecular systems, surface phenomena, and nanostructures with unprecedented spatial precision, offering potential for research in chemistry, materials science, bio-macromolecules, and nanotechnology for the chemical physics community.