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The reactivity of Ta <i>n</i> + clusters with NO molecules: N–O bond dissociation and NO <i>x</i> conversion
Nitric oxides are primary contributors to air pollution. Examining their chemical transformations is crucial for developing effective clean air strategies. In this study, we studied the reactions between cationic tantalum clusters Tan+ (n = 1–16) and NO, utilizing our customized laminar flow tube reactor coupled with a tandem quadrupole mass spectrometer. The experimental results indicate that the reaction pathways of Tan+ clusters vary with cluster size: for smaller tantalum clusters Tan+ (n ≤ 5), the reaction products are mainly composed of TanN+ and TanO+, suggesting direct N–O dissociation or bimolecular reaction to release N2O or NO2 mediated by small metal clusters. In contrast, the larger clusters Tan≥6+ exhibit a range of reaction products, facilitated by the favorable adsorption of multiple molecules to generate the Tan(NO)m+ and TanO(NO)m+ series. Theoretical calculations reveal that the energetics and reaction dynamics differ among Tan+ clusters of varying sizes. This study clarifies the substantial size effect of the Tan+ clusters in reactions with nitric oxide and underscores the importance of small Ta clusters for NO elimination and NOx conversion.
PhenoProfiler: advancing phenotypic learning for image-based drug discovery
Quantum dynamics of electron transfer in single-molecule systems coupled to polaritons: A macroscopic quantum electrodynamics approach
Controlling electron transfer and related chemical processes through polaritons has emerged as a promising direction in chemical physics. We present a general framework for electron transfer in molecules strongly coupled to polaritons. The theory is formulated within macroscopic quantum electrodynamics, a quantization scheme for electromagnetic fields in non-homogeneous, dispersive, and lossy media. To capture both molecular and dielectric contributions, our formulation incorporates two baths: molecular vibrations and a dielectric-photonic continuum that generates polaritons. This formulation is then transformed into a numerically tractable form that can be naturally combined with methods such as the pseudomode approach or the hierarchical equations of motion. Using a molecule above a plasmonic surface as an example, we show that the framework captures accurate dynamics across light–matter coupling regimes, thereby providing a powerful tool for investigating polariton-mediated electron transfer.
Divergent transcriptional regulation of redox-homeostasis and permeability modulate rifampicin tolerance and sensitivity in Mycobacterium tuberculosis
Ground-and excited-state fragmentation dynamics of doubly ionized OCS: A theoretical study
We investigated fragmentation dynamics of OCS2+ after photoinduced double ionization by combining static potential energy surface (PES) analysis with ab initio molecular dynamics (AIMD) and surface-hopping AIMD (SH-AIMD). In the ground state, AIMD shows that the isomerization pathway from OCS2+ to COS2+, although accessible on the static PES, is dynamically hidden. Trajectories rarely follow it because it requires unrealistically high bending excitation, whereas S+ dissociation proceeds without such a constraint. Consequently, energy released upon ionization is funneled more efficiently into dissociation, favoring S+ dissociation over isomerization. For excited states, SH-AIMD trajectories launched from the lowest triplet 3Π states and the 23Δ state reproduce the observed fragmentation: predominant S+ dissociation with minor O+ formation. The isomerization process leading to the COS2+ structure was not observed in the simulations. These results are consistent with experimental observations. Notably, for the O+ channel, we likely achieve the first AIMD reproduction of the experimental appearance threshold using only triplet states and no external laser fields. This indicates that vibronic coupling via bending motion is essential to enable O+ release, although its probability remains small relative to S+ dissociation. Overall, fragmentation in OCS2+ is governed by the interplay of vibronic coupling and dynamical effects: bending vibrations can facilitate O+ release, whereas isomerization to COS2+ is dynamically suppressed by the requirement of extreme bending excitation. The high density of states in the excited manifold further underscores the strongly nonadiabatic character of OCS2+. Our results connect static PES features with trajectory-based dynamics, offering new insight into selective fragmentation in polyatomic dications.
Targeting LRBA triggers CTLA4 degradation and antitumor immunity for cancer immunotherapy
The geometry of the classical action in phase space
We present a geometric representation in phase space of the classical action. Specifically, we find three seemingly unrelated interpretations for the action as the sum of signed areas of shapes in phase space. By using the Poincaré–Cartan integral invariants in extended phase space, we are able to show the equivalence between all three. As a concrete example, we consider the 1D harmonic oscillator, but the results are general for arbitrary potentials and numbers of dimensions.
All-optical hybrid metasurfaces for ultrafast computational spectrometer and single-pixel imaging
Inferring intermediate states by leveraging the many-body Arrhenius law
Metastable states appear as long-lived intermediate states in various natural transport phenomena, which are governed by energy landscapes. As such, these intermediate metastable states dominate the system’s dynamics at coarse grained times. Moreover, they can strongly influence the overall pathways through which the energy landscape is explored. Therefore, quantifying these metastabilities is crucial for uncovering the key details of the underlying landscape. Here, we introduce a robust method based on a generalized many-body Arrhenius law to identify metastable states in escape problems involving interacting particles with excluded volume. Experimental platforms such as colloidal transport or macromolecular translocation through biological pores can offer promising settings to validate our predictions.
SPOROCYTELESS/NOZZLE cooperates with MADS-domain transcription factors to regulate an auxin-dependent network controlling Megaspore-Mother-Cell differentiation
Abstract The formation of the female gamete is a complex developmental process that begins with the differentiation of the Megaspore Mother Cell (MMC) within the ovule. SPOROCYTELESS/NOZZLE (SPL/NZZ) is the principal regulator of the MMC formation, as mutations in the SPL/NZZ gene lead to the failure of the MMC differentiation. Nonetheless, the SPL/NZZ-dependent regulatory pathway governing the MMC development remains largely unknown. Using a multi-omics approach, we identify direct SPL/NZZ targets and their downstream network. We discover that SPL/NZZ interacts with ovule-identity MADS-domain transcription factor complexes to regulate the expression of common target genes. By integrating the omics data with the analysis of either complementation or mutant lines, we describe a comprehensive regulatory mechanism in which SPL/NZZ controls the differentiation of the MMC by acting on an auxin-dependent downstream network.
Hierarchical equations of motion solved with the multiconfigurational Ehrenfest ansatz
Being a numerically exact method for the simulation of dynamics in open quantum systems, the hierarchical equations of motion (HEOM) approach still suffers from the curse of dimensionality. In this study, we propose a novel multiconfigurational Ehrenfest (MCE)-HEOM method, which introduces the MCE ansatz to the second quantization formalism of HEOM. Here, the MCE equations of motion are derived from the time-dependent variational principle in a composed Hilbert–Liouville space, and each MCE coherent-state basis can be regarded as having an infinite hierarchical tier such that the truncation tier of auxiliary density operators in MCE-HEOM can also be considered to be infinite. As demonstrated in a series of representative spin-boson models, our MCE-HEOM significantly reduces the number of variational parameters and could efficiently handle the strong non-Markovian effect, which is difficult for conventional HEOM due to the requirement of a very deep truncation tier. MCE-HEOM is further applied to the 7-site Fenna–Matthews–Olson complex to study energy transfer in photosynthesis, and the results indicate that multi-site and multi-bath cases can also be accurately described with high efficiency. Compared to MCE, MCE-HEOM reduces the number of effective bath modes and circumvents the initial sampling for finite temperatures, eventually resulting in a significant reduction in computational cost.
ARMH4 accelerates aging by maintaining a positive-feedback growth signaling circuit
On the interconnection between products formed by dissociative electron attachment to gas-phase abscisic acid and its microbial (but not plants) metabolic pathways
Low-energy (0–14 eV) electron-driven processes in a racemic mixture of the chiral abscisic acid (ABA) molecules are studied using dissociative electron attachment (DEA) spectroscopy under gas-phase conditions. DFT calculations are employed to understand the electronic structure of the ABA molecule to assign the experimental findings. The lowest two normally empty π* molecular orbitals of ABA are predicted to lie in a bound region, whereas the vertical electron attachment energy to occupy the π3* LUMO+2 orbital is estimated to be 1.33 eV. The long-lived (90 μs) parent molecular negative ions are formed by thermal electron attachment via vibrational Feshbach resonance. The adiabatic electron affinity of the ABA molecule is experimentally estimated to be about 0.9 eV. With very few exceptions, the fragmentation of ABA by resonance electron attachment occurs at thermal electron energy, the dominant decay being associated with the formation of the 4-oxoisophorone negative ion (m/z = 152) and the isomeric form of the sorbic acid molecule as a neutral counterpart. The structure of ABA microbial metabolites coincides with that of the DEA products with m/z = 152, 204, and 220 and of the neutral species generated as a counterpart of the m/z = 111 negative ions. The likely relation of these findings to electron-triggered biological processes is briefly discussed in the framework of electron donation to ABA from the microbial nanowires.
RETRACTED ARTICLE: Implantable neural probes with monolithically integrated CNTFET arrays for multimodal monitoring
Structural characterisation of the fungal Pmt4 homodimer
Abstract Protein O-mannosyltransferases (PMTs) are conserved endoplasmic reticulum membrane-embedded enzymes responsible for the transfer of mannose from dolichol phosphate-mannose (Dol-P-Man) to serine/threonine-rich protein substrates or unfolded proteins. PMTs from three subfamilies form obligate dimers with different substrate specificities and require the concerted action of their transmembrane domains (TMDs) and a luminal MIR domain for catalysis. Here, we present structures, native mass spectrometry, and structure-based mutagenesis of the fungal Pmt4 homodimer. The core fold of the TMDs and MIR domain is conserved with the Pmt1-Pmt2 heterodimer, indicating a shared catalytic mechanism. Distinct from Pmt4, the MIR domain interacts in cis with the TMDs of the same subunit and has a β-hairpin insertion required for O-mannosylation of substrates. We further identify a cytosolic binding site for substrate Dol-P-Man within the Pmt4 TMDs, which is conserved amongst PMTs and important for in vivo activity. Thus, we provide a framework to understand the substrate specificity and regulation of the Pmt4 homodimer.
Cell type-specific functions of the PBAF chromatin-remodeling complex in neuronal diversification
Compression-induced NF-κB activation sustains tumor cell survival in confinement by detoxifying aldehydes and promotes metastasis
Abstract Metastasis remains the primary cause of cancer-related mortality. During dissemination, cancer cells must navigate spatially confined microenvironments, yet the underlying metabolic adaptations that facilitate this process remain unclear. Here, through an in vivo CRISPR screen targeting metabolic enzymes, we identify aldehyde dehydrogenase 1 family member B1 (ALDH1B1) as essential for tumor cell survival in confining capillaries. Mechanistically, compressive force induces casein kinase 2 alpha 3 (CSK23) to phosphorylate kappa-B kinase subunit beta (IKKβ) at Ser177/181, which activates the nuclear factor kappa B (NF-κB) pathway and upregulates ALDH1B1. The upregulation of ALDH1B1 enhances aldehyde detoxification, which suppresses ferroptosis and promotes tumor cell survival during migration through the capillaries, thereby facilitating metastasis. Importantly, genetic or pharmacological inhibition of CSK23 or ALDH1B1 effectively impairs metastasis. In lung cancer patients, confined tumor cells exhibit higher levels of ALDH1B1 and NF-κB activation, which correlates with metastatic recurrence. Our findings reveal a mechano-metabolic pathway that promotes metastasis and suggest CSK23 and ALDH1B1 as potential therapeutic targets.