More Like this

1. Exploring the Role of Wave‐Driven Turbulence at the Air‐Sea Interface Through Measurements of TKE Dissipation Rates Across the Air‐Sea Interface

   https://doi.org/10.1029/2023JC020308  

   Cifuentes‐Lorenzen, Alejandro; Zappa, C_J; Edson, J_B; O’Donnell, J.; Ullman, D_S (August 2024, Journal of Geophysical Research: Oceans)

   Abstract This work serves as an observation‐based exploration into the role of wave‐driven turbulence at the air‐sea interface by measuring Turbulent Kinetic Energy (TKE) dissipation rates above and below the sea surface. Subsurface ocean measurements confirm a TKE dissipation rate enhancement relative to the predicted law‐of‐the‐wall (ε_obs > ε_p), which appears to be fully supported by wave breaking highlighting the role of the transport terms in balancing the subsurface TKE budget. Simultaneous measurements of TKE dissipation rates on the atmospheric side capture a deficit relative to the law‐of‐the‐wall (ε_obs < ε_p). This deficit is explained in terms of wave‐induced perturbations, with observed convergence to the law‐of‐the‐wall at 14 m above mean sea level. The deficit on the atmospheric side provides an estimate of the energy flux divergence in the wave boundary layer. An exponential function is used to integrate in the vertical and provide novel estimates of the amount of energy going into the wave field. These estimates correlate well with classic spectral input parameterizations and can be used to derive an effective wave‐scale, capturing wind‐wave coupling purely from atmospheric observations intimately tied to wave‐induced perturbations of the air‐flow. These atmospheric and oceanic observations corroborate the commonly assumed input‐dissipation balance for waves at wind speeds in the 8‐14 ms⁻¹range in the presence of developed to young seas. At wind speeds above 14 ms⁻¹under young seas ()observations suggest a deviation from the TKE input‐dissipation balance in the wave field. 

   more » « less
2. A bioinspired and degradable riboflavin-containing polypeptide as a sustainable material for energy storage

   https://doi.org/10.1073/pnas.2509325122  

   Li, Shih-Guo; Mohanty, Khirabdhi T; Easley, Alexandra D; Rezenom, Yohannes H; Lim, Soon-Mi; Gillett, Leyla P; Naquin, Stone D; Tran, David K; Nguyen, Tan P; Lutkenhaus, Jodie L; et al (July 2025, Proceedings of the National Academy of Sciences)

   Inspired by Nature, we present a polypeptide-based organic redox-active material constructed from renewable feedstocks, L-glutamic acid (an amino acid) and riboflavin (vitamin B₂), to address challenges with start-to-end-of-life management in energy storage systems (ESSs). The amino acid was utilized to establish a degradable polymer backbone, along which many copies of riboflavin were incorporated to serve as the redox-active pendant groups that enabled energy storage. The overall synthesis involved the ring-opening polymerization (ROP) of anl-glutamic acid-derivedN-carboxyanhydride (NCA) monomer, followed by side chain activation with azides and, finally, click coupling to achieve installation of alkyne-functionalized riboflavin moieties. The steric bulkiness and rich chemical functionality of riboflavin resulted in synthetic complexities that required reaction optimization to achieve the desired polymer structure. Electrochemical characterization of the resultant riboflavin polypeptide, in organic electrolyte, showed quasireversible redox activity with a half-wave potential (E_1/2) ofca.−1.10 Vvs.ferrocene/ferrocenium (Fc/Fc⁺). Cell viability assays revealed biocompatibility, as indicated by negligible cytotoxicity for fibroblast cells. The polypeptide design, consisting of labile amide backbone linkages and side-chain ester functionalities that tethered the riboflavin units to the backbone, enabled hydrolytic degradation to recover building blocks for future upcycling or recycling. This bioinspired strategy advances the development of degradable redox-active polymers and promotes sustainable materials design for circular energy storage technologies. 

   more » « less
3. High‐Temperature and High‐Energy‐Density Dipolar Glass Polymers Based on Sulfonylated Poly(2,6‐dimethyl‐1,4‐phenylene oxide)

   https://doi.org/10.1002/anie.201710474  

   Zhang, Zhongbo; Wang, David H.; Litt, Morton H.; Tan, Loon‐Seng; Zhu, Lei (January 2018, Angewandte Chemie International Edition)

   Abstract A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO₂‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation of highly polar methylsulfonyl side groups below the glass transition temperature (T_g≈220 °C), the dipolar polarization of these SO₂‐PPOs was enhanced, and thus the dielectric constant was high. Consequently, the discharge energy density reached up to 22 J cm⁻³. Owing to its highT_g , the SO₂‐PPO₂₅sample also exhibited a low dielectric loss. For example, the dissipation factor (tan δ) was 0.003, and the discharge efficiency at 800 MV m⁻¹was 92 %. Therefore, these dipolar glass polymers are promising for high‐temperature, high‐energy‐density, and low‐loss electrical energy storage applications. 

   more » « less
4. Manipulating Conjugated Polymer Backbone Dynamics through Controlled Thermal Cleavage of Alkyl Side Chains

   https://doi.org/10.1002/marc.202200533  

   Zhao, Haoyu; Shanahan, Jordan J.; Samson, Stephanie; Li, Zhaofan; Ma, Guorong; Prine, Nathaniel; Galuska, Luke; Wang, Yunfei; Xia, Wenjie; You, Wei; et al (August 2022, Macromolecular Rapid Communications)

   Abstract The morphological stability of an organic photovoltaic (OPV) device is greatly affected by the dynamics of donors and acceptors occurring near the device's operational temperature. These dynamics can be quantified by the glass transition temperature (T_g) of conjugated polymers (CPs). Because flexible side chains possess much faster dynamics, the cleavage of the alkyl side chains will reduce chain dynamics, leading to a higherT_g. In this work, theT_gs for CPs are systematically studied with controlled side chain cleavage. Isothermal annealing of polythiophenes featuring thermally cleavable side chains at 140 °C, is found to remove more than 95% of alkyl side chains in 24 h, and raise the backboneT_gfrom 23 to 75 °C. Coarse grain molecular dynamics simulations are used to understand theT_gdependence on side chain cleavage. X‐ray scattering indicates that the relative degree of crystallization remains constantduring isothermal annealing process. The effective conjugation length is not influenced by thermal cleavage; however, the density of chromophore is doubled after the complete removal of alkyl side chains. The combined effect of enhancingT_gand conserving crystalline structures during the thermal cleavage process can provide a pathway to improving the stability of optoelectronic properties in future OPV devices. 

   more » « less
5. Deciphering the combinatorial expression pattern and genetic regulatory mechanisms of Beats and Sides in the olfactory circuits of Drosophila

   https://doi.org/10.1101/2025.05.31.657193  

   Duan, Ǫichen; Okuwa, Sumie; Estrella, Rachel; Yeung, Chun; Chen, Yu-Chieh David; Rio, Laura Ǫuintana; Vien, Khanh M; Volkan, Pelin C (June 2025, bioRxiv)

   Abstract Over the past decades, many critical molecular players have been uncovered to control distinct steps in olfactory circuit assembly in Drosophila. Among these, multi-member gene families of cell surface proteins are of interest because they can act as neuron-specific identification/recognition tags in combinations and contribute to circuit assembly in complex brains through their heterophilic or homophilic interactions. Recently, a multi-protein interactome has been described between the Beat and Side families of IgSF proteins. Here, we use the publicly available single-cell RNA-seq datasets and newly generated gene trap transgenic driver lines to probe thein vivospatial expression pattern of thebeat/sidegene families in odorant receptor neurons (ORNs) and their synaptic target projection neurons (PNs).Our results revealed that each ORN and its synaptic target PN class expresses a class-specific combination ofbeat/sidegenes, hierarchically regulated by lineage-specific genetic programs. Though ORNs or PNs from closer lineages tend to possess more similarbeat/sideprofiles, we also found many examples of divergence from this pattern among closely related ORNs and closely related PNs. To explore whether the class-specific combination ofbeats/sidesdefines ORN-PN matching specificity, we perturbed presynapticbeat-IIaand postsynapticside-IVin two ORN-PN partners. However, disruption of Beat-IIa-Side-IV interaction did not produce any significant mistargeting in these two examined glomeruli. Though without affecting general glomerular targeting, knockdown ofsidein ORNs leads to the reduction of synaptic development. Interestingly, we found conserved expression patterns ofbeat/sideorthologs across ORNs in ants and mosquitoes, indicating the shared regulatory strategies specifying the expression of these duplicated paralogs in insect evolution. Overall, this comprehensive analysis of expression patterns lays a foundation for in-depth functional investigations into how Beat/Side combinatorial expression contributes to olfactory circuit assembly. 

   more » « less