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Upon laser irradiation, 2D materials experience a cascading energy transfer from electrons to optical phonons (OPs) and then to acoustic phonons (APs), resulting in a significant thermal non-equilibrium among energy carriers. This non-equilibrium presents challenges for Raman-based thermal characterization, as Raman scattering measures only OP temperature rise, while APs are the primary energy carriers. Despite recent efforts to address this issue, OP–AP thermal non-equilibrium in supported 2D materials remains poorly resolved. Here, we develop a method to distinguish the OP and AP temperature rises based on their different temporal thermal responses under laser irradiation: the OP–AP temperature difference responds almost immediately (∼a few to tens of ps), while the AP temperature rise takes longer to establish (∼tens of ns). Using energy transport-state resolved Raman, we probe the transient thermal response of Si-supported nm-thick MoS₂from 20 to 100 ns. We find that the OP–AP temperature difference exceeds 120% of the AP temperature rise under ∼0.439 µm radius laser heating. The intrinsic interfacial thermal conductance of the samples, based on the true AP temperature rise, varies from 0.199 to 1.46 MW·m⁻²·K⁻¹, showing an increasing trend with sample thickness. 

In yeasts and higher eukaryotes, chromatin motions may be tuned to genomic functions, with transcriptional activation and the DNA damage response both leading to profound changes in chromatin dynamics. The RAD51 recombinase is a key mediator of chromatin mobility following DNA damage. As functions of RAD51 beyond DNA repair are being discovered, we asked whether RAD51 modulates chromatin dynamics in the absence of DNA damage and found that inhibition or depletion of RAD51 alters chromatin motions in undamaged cells. Inhibition of RAD51 increased nucleosome clustering. Predictions from polymer models are that chromatin clusters reduce chain mobility and, indeed, we measured reduced motion of individual chromatin loci in cells treated with a RAD51 inhibitor. This effect was conserved in mammalian cells, yeasts, and plant cells. In contrast, RAD51 depletion or inhibition increased global chromatin motions at the microscale. The results uncover a role for RAD51 in regulating local and global chromatin dynamics independently from DNA damage and highlight the importance of considering different physical scales when studying chromatin dynamics. 

The bistability and the conductivity changes associated with optical excitations in cobalt valence tautomer molecular thin films were investigated. 

Sodium-ion batteries (SIBs) is a promising technology for next-generation energy storage. However, their performance is limited at low temperatures due to the inferior bulk and interfacial resistance of current electrolytes. Here we present a systematic study to evaluate carboxylate ester-based electrolytes for SIB applications, due to their favorable properties (i.e., low melting point, low viscosity and high dielectric constant). The effects of salt, concentration and solvent molecular structure were systematically examined and compared with those of carbonate-based electrolytes. By combining electrochemical tests with spectroscopic characterization, the performance of selective carboxylate ester-based electrolytes in hard carbon/Na and Na3V2(PO4)3/Na half-cells was evaluated. We found carboxylates enable high electrolyte conductivities, especially at low temperatures. However, carboxylates alone are inadequate to form a stable interphase due to their high reactivity, which can be addressed by choosing a suitable anion and facilitating anion-rich Na+ solvation by increasing salt concentration. Fundamental knowledge on the chemistry–property–performance correlation of this new family of electrolytes was obtained, and their benefits and pitfalls were thoroughly discussed. These discoveries and knowledge will shed light on the potential of carboxylate ester-based electrolytes and provide the foundation for further electrolyte engineering. 

ABSTRACT Nonmuscle myosin II (NMII) generates cytoskeletal forces that drive cell division, embryogenesis, muscle contraction and many other cellular functions. However, at present there is no method that can directly measure the forces generated by myosins in living cells. Here, we describe a Förster resonance energy transfer (FRET)-based tension sensor that can detect myosin-associated force along the filamentous actin network. Fluorescence lifetime imaging microscopy (FLIM)-FRET measurements indicate that the forces generated by NMII isoform B (NMIIB) exhibit significant spatial and temporal heterogeneity as a function of donor lifetime and fluorophore energy exchange. These measurements provide a proxy for inferred forces that vary widely along the actin cytoskeleton. This initial report highlights the potential utility of myosin-based tension sensors in elucidating the roles of cytoskeletal contractility in a wide variety of contexts.