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Collective Rabi-driven vibrational activation in molecular polaritons
No full textHybrid light-matter states, known as molecular polaritons, arise from electronic or vibrational strong coupling (ESC and VSC) with confined electromagnetic fields. While these have been widely studied, the influence of electron-nuclear dynamics in driven cavities remains largely unknown. Here, we report a previously unrecognized mechanism of vibrational activation that emerges under collective ESC in driven optical cavities. Using semiclassical simulations that self-consistently combine Maxwell's equations with quantum molecular dynamics, we show that collective electronic Rabi oscillations coherently drive nuclear motion. This effect is captured using both vibrational wave-packet dynamics in a minimal two-level model and atomistic simulations based on time-dependent density-functional tight-binding with Ehrenfest dynamics. Vibrational activation depends non-monotonically on the Rabi frequency and is maximized when the collective polaritonic splitting resonates with a molecular vibrational mode. The mechanism exhibits features consistent with a stimulated Raman-like relaxation mechanism. Our results establish a self-consistent framework for realistic cavity-electron-nuclear dynamics
Direct detection of SABRE-SHEATH hyperpolarization and spin-lattice relaxation of [1-13C]pyruvate
No full textNuclear magnetism is typically investigated by perturbing the spin system with radio frequency pulses, but low polarization and detection using induction coils limit direct access to the longitudinal magnetization. The hyperpolarization technique SABRE-SHEATH requires ultra-low magnetic fields for spin order transfer; consequently, SQUID sensors with a frequency-independent sensitivity are well-suited for unperturbed detection in this regime. We demonstrate direct observation of hyperpolarization build up (TB) and spin lattice relaxation (T1) in [1-13C]pyruvate, hyperpolarized with SABRE-SHEATH at 150 nT and 500 nT. The values for TB of 36 s and 26 s and T1 of 40 s and 43 s, respectively, suggests a shift in dominant polarization transfer efficacy or complexes, highlighting the method's merit in characterizing hyperpolarization pathways. Moreover, as demand for hyperpolarized probes in metabolic imaging continues to grow, the exceptional time resolution makes direct detection a valuable tool for understanding and optimizing polarization dynamics and reactor designs
The geometry of tilting composition series via Richardson varieties
No full textWe prove the (graded) Jordan-Hölder multiplicities of (mixed) tilting sheaves on flag varieties admit a geometric interpretation as the hypercohomology of certain sheaves on Richardson varieties in the Langlands dual flag variety. These sheaves are a motivic variant of geometric extensions, and provide a replacement for parity sheaves on the Richardson variety. We also provide an explicit formula for these multiplicities in terms of -Kazhdan-Lusztig polynomials
In vitro transcriptome and proteome of Haemonchus contortus larvae exposed to host blood components
No full textHematophagy is essential for the survival and development of blood-feeding nematodes, including Haemonchus contortus (the barber's pole worm) - a gastrointestinal nematode model for the study of anthelmintic resistance and drug discovery. Upon host ingestion, the infective larvae of this nematode transit to parasitic stage, then consume blood, contributing to the pathology of haemonchosis, a disease responsible for substantial economic losses. However, this process cannot be replicated in vitro without blood supplements. Therefore, despite genomic insights into developmental biology and anthelmintic resistance mechanisms, hematophagy remains poorly understood in this and other blood-feeding species. Here, we present a transcriptome dataset from the in vitro-cultured parasitic larvae of H. contortus exposed to 100 µM hemin chloride, 10% serum, and 10% defibrinated blood of host animals. A proteomic dataset for the in vitro-cultured larvae exposed to 10% serum is also available. These resources enable exploration of blood-component-specific transcriptomic reprogramming, hub gene-driven translational/metabolic modules, and molecular adaptations. This dataset also enables identification of genes critical for blood-feeding adaptation and parasitism, advancing therapeutic targets for intervention
Single-cell characterization of the adult male hippocampus suggests a prominent, and cell-type specific, role for Nrgn and Sgk1 in response to a social stressor
No full textStress-related psychiatric disorders impact the quality of life of half a billion people around the world. However, our understanding of the molecular mechanisms responsible for stress-response regulation remain unclear. Here, we report the largest and most comprehensive characterization of the adult male mouse hippocampus, under baseline and acute stress condition, using single-cell RNA sequencing. We further used genetically modified knockout lines for the glucocorticoid and mineralocorticoid receptors (GR and MR); two transcription factors which are pivotal regulators of the central stress-response. We found previously unknown, cell-type specific, molecular signatures of a single prolonged social defeat stress response and identified Nrgn and SgK1 as key regulators in stress-responsive glutamatergic neurons, oligodendrocytes, astrocytes, and endothelial cells. Intriguingly, GR or MR deletion, specifically in glutamatergic or GABAergic neurons, led to distinct and cell-type specific transcriptional signatures after stress exposure. This study significantly advances our understanding of the molecular and cellular network underlying the central response to stressful stimuli
Nano-scale evidence for osteocyte network integration across bone remodeling interfaces in human bone revealed by synchrotron nanoCT
No full textBone remodeling is a highly regulated, hierarchical process critical for maintaining structural integrity and mineral homeostasis. At the nano-scale, the osteocytes orchestrate mechanosensing, signaling, and nutrient transport across the mineralized matrix utilizing their extensive network of cell dendrites. The lacunar-canalicular network (OLCN) houses the cellular components within the matrix. How this network integrates across bone regions formed during different remodeling cycles remains unresolved. How the cellular network is connected across interfaces between different remodeling regions or cement lines is the focus of this exploration: is the network integration merely stochastical occurrences or result of a cued, directed formation process? Using synchrotron-based nano computed tomography (nano-CT), we analyze human bone samples of 35 different patients with sub-micron resolution to characterize canalicular structures around cement lines. The results show the network's ability and affinity to integrate, and the strong influence of local tissue conditions on the degree of integration. We novelly include the structural analysis of canalicular network architecture to interpret underlying formation processes. Besides 'cross-generational' canalicular connections, we identify previously overlooked canalicular loops in newly formed bone near cement lines and interpret these as morphological indicators of a directed, adaptive search for reconnection. The study suggests a mechanism combining random outgrowth and directed progression influenced by local cues. We propose a 'cross-generational' OLCN: a deliberately integrated network that enhances tissue connectivity, functional resilience, and osteocyte survival across temporal remodeling stages. These findings advance the understanding of bone network complexity and introduce canalicular looping as a nano-structural signature of directed formation in bone network architecture
Canonical differential equations beyond polylogs
No full textFeynman integrals whose associated geometries extend beyond the Riemann sphere, such as elliptic curves and Calabi-Yau varieties, are increasingly relevant in modern precision calculations. They arise not only in collider cross-section calculations, but also in the post-Minkowskian expansion of gravitational-wave scattering. A powerful approach to compute integrals of this type is via differential equations, particularly when cast in a canonical form, which simplifies their -expansion and makes analytic properties manifest. In these proceedings, we will present a method to systematically construct canonical differential equations even for integrals that evaluate beyond multiple polylogarithms. The discussion is kept as light as possible, focusing on the two-loop sunrise integral, deferring the technical details to the original publications
