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The subject of viscoelastic flow phenomena is crucial to many areas of engineering and the physical sciences. Although much of our understanding of viscoelastic flow features stems from carefully designed experiments, preparation of model viscoelastic fluids remains a challenge; for example, fabricating a series of fluids with different fluid shear moduli G0, but with an identical relaxation time τ, is nontrivial. In this work, we harness the nonideality of nearly constant-viscosity elastic fluids, commonly known as “Boger fluids,” made with polyisobutylene (PIB), to develop an experimental methodology that produces a set of fluids with desired viscoelastic properties, specifically, G0, τ, and the first normal stress difference coefficient ψ1. Through a linear algebraic relation between the rheological properties of interest (G0, τ, ψ1) and the fluid compositions in terms of polymer concentration c, molecular weight M, and solvent viscosity ηs, we developed a “design equation” that takes G0, τ, ψ1 as inputs and calculates values for c, M, ηs as outputs. Using this method, fabrication of dilute viscoelastic fluids whose rheological properties are a priori known can be achieved. 

Liquid interfaces appear throughout nature and engineering and are typically contaminated by surface active agents (surfactants), which are characterized by a wide range of solubility. We demonstrate that solubility enhances by an order of magnitude surfactant-induced flow in air-liquid-air films, in contrast to previously studied geometries where solubility dampens the flow. The enhancement is described by a single parameter comparing the depletion length to the film thickness. Our experiments are well described by an asymptotic theory of the Navier-Stokes equations, including surfactant kinetics. 

IntroductionMast cell stabilizers (MCS) have the potential to address unmet therapeutic need in allergy and inflammation management. MCS chronically suppress all arms of the pro-inflammatory mast cell response to stimulation (e.g., histamine, protease, lipid mediators, cytokines and chemokines). They may therefore outperform approaches such as H1, H2 and H4 inhibitors (antihistamines), which block only the acute histamine release by mast cells and leave the rest of the functional response untouched. Despite their potential, current MCS (e.g., cromolyn sodium, tranilast, nedocromil) in clinical use are hindered by poor bioavailability, frequent dosing, long lags to onset of relief, and enigmatic mechanisms of action. MCS have their origins in phytomedicine: cromolyn sodium is the longest standing drug in the class and is a derivatized form of khellin fromAmmi visnaga,used as an anti-inflammatory. Other plant-based pharmacopeias may offer candidate ‘next-generation’ MCS (ngMCS) and in this study we hypothesized that a coupled pharmacoanalytic andin vitropharmacology approach could be used to identify, prioritize and derisk additional candidate MCS from phytomedical sources for later preclinical and clinical evaluation. MethodsWe report a novel data analytics workflow starting with a newly developed plant-based pharmacopeia data platform with >3.5B linkage pathways (country → medical system → formulation → indication → ingredient organism → chemical component → other parameters), covering 22 M sq. miles of biogeography and historical and contemporary timeframes. Additional data layers include druggability indices, target and pathway analyses. ResultsThe current study validates a subset of candidate phytomedical ngMCS usingin silicoworkflow andin vitropharmacology, and develops a new harmonic mean-based ‘MCS score’ for further streamlining of the candidate prioritization process. DiscussionThis proof-of-concept study may have particular relevance for complex presentations such as Mast Cell Activation Syndrome (MCAS) where ngMCS may outperform current management approaches. 

Two-fluid spray nozzles are widely used in combustion, chemical processing, pharmaceutical coating, environmental control, and spray drying to atomize liquids with pressurized gas. However, the adiabatic cooling of the atomizing gas and the resulting flash freeze–thaw exposure of the atomized droplets remain underexplored. Using high-fidelity computational fluid dynamics and droplet-scale nucleation modeling for a drying chamber equipped with a two-fluid nozzle, we show that the temperature of the atomizing gas can drop from 22 °C to below −130 °C at the nozzle exit, triggering rapid ice nucleation and freezing in micrometer-scale spray droplets. For the atomizing gas supplied at 5 bar and 22 °C, all droplets smaller than 1.5 μm freeze, whereas droplets larger than 3 μm remain liquid. The frozen droplets then thaw within O(10) μ s after leaving the cold zone. As a result, sensitive actives can be exposed to intense freeze–thaw thermomechanical stresses near the nozzle, even when the bulk drying gas is warm. Parametric studies show that ice formation is eliminated under two conditions: (1) raising the atomizing gas temperature above 110 °C suppresses freezing across all gas-to-liquid mass ratios (GLRs) studied, from 8 to 25, and (2) reducing the GLR below 12 prevents ice formation at any atomizing gas temperature in the investigated range of 22–140 °C. By contrast, the drying-gas temperature in the chamber does not affect near-nozzle freezing. We also show that swirling flow in the nozzle intensifies flash freeze–thaw by deepening gas cooling, whereas non-swirling flow prolongs residence time in the cold zone. Despite these differences, both designs produce similar fractions of iced droplets. Finally, we construct an operating map that delineates conditions that avoid flash freeze–thaw and show that the no-ice boundary provides a conservative criterion for both swirl and non-swirl nozzles. These findings identify a previously unrecognized freeze–thaw stress mechanism that may compromise the stability of spray-dried pharmaceutical products. 

Phytomedicines are key to global healthcare and underutilized in Western medical systems. The inherent complexity of multi-species polypharmaceutical formulations presents barriers (standardization, reproducibility and regulatory approval) that can relegate potentially safe, effective and lower cost medication to nutraceutical settings in countries such as the US. The identification of Minimal Essential Effective Formulations (MEEFs) is a strategy to rationally simplify phytomedicines while preserving efficacy, but it requires computational innovation to de-risk and prioritize compounds due to the time and resource burden of conventional screening. We developed a computational framework that operationalizes a Chief–Deputy–Assistant–Envoy (CDAE) Asian medicine heuristic used to assemble ingredient organisms in formulations but translates it to the compound level. We deployed a novel high-content, multi-ontology data platform (PhAROS™, Phytomedical Analytics for Research Optimization at Scale) that aggregates open-source data from 8 global medical systems comprising ∼6B multiwise linkages across organisms, indications, formulations, compounds and targets, with additional data layers providing decision support based on druggability indices and absorption-distribution-metabolism-excretion (ADME). Using PhAROS™, we defined and computationally classified “chief” compounds using pain formulations as a test case. Kernel density estimation and network centrality analyses revealed that Chief compounds exhibit favorable pharmacokinetic profiles and occupy highly connected positions in formulation-target networks. Cross-system similarity analyses further demonstrated non-random convergence in species, compound, and target usage across disparate medical systems, suggesting that biogeographically and culturally independent practices have arrived at biomedically robust solutions. This work demonstrates a proof of concept for enabling rational complexity reduction for phytomedicines, bridging traditional formulation logic with pharmacological informatics. 

IntroductionPhytomedicines have played a vital role in traditional medical systems globally, particularly in providing culturally relevant and accessible healthcare solutions.P. methysticum, known as Kava, is a traditional Pacific Island phytomedicine with clinically validated anxiolytic properties, primarily attributed to its Kavalactones (KL). However,P. methysticumis biogeographically restricted and there are ecological and cultural concerns that limits its widespread therapeutic adoption. This study investigates if otherPiperspecies, used phytomedically outside the Pacific, offer therapeutic efficacy for anxiety, stress, and related disorders as alternatives to Kava. We used a hybrid computational and experimental validation approach. MethodsA new data platform aggregating non-Western phytomedical pharmacopeias was used to analyze the secondary metabolomes of variousPiperspecies. Network analysis and multidimensional data projections compared chemical composition and therapeutic indications of these species with those ofP. methysticum. ResultsOur findings suggest that while Kavalactones are predominantly unique toP. methysticum, otherPiperspecies also contain bioactive compounds associated with anxiolytic and stress-relieving effects, a subset of which were validated in anin vivomodel pilot study. DiscussionThese findings identify new potential avenues for exploration of phytomedical solutions to complex interconnected sleep, pain, stress, movement and anxiety issues that hallmark disorders such as PTSD and Parkinson’s. 

Physical Review . Polynyas—persistent regions of open water within polar sea ice—play a critical role in polar ocean-atmosphere interactions. We combine theoretical modeling and numerical simulations to investigate the dynamics and thermodynamics of wind-driven, latent-heat-generated polynya formation adjacent to straight and curved coastlines. Under the assumption of negligible ice internal pressure, we propose a one-dimensional, continuum, mass- and momentum-conserving theory characterizing the offshore distribution of ice velocity and the spatiotemporal evolution of ice concentration. Finite-element simulations incorporating realistic sea-ice rheology validate the theoretical predictions, demonstrating strong agreement in steady-state polynya widths and ice dynamics. These results align qualitatively with observational climate data. Furthermore, we generalize the framework to two dimensions, enabling quantitative predictions of leeward polynya formation around a model circular island. The proposed theoretical framework advances mechanistic understanding of polynya formation and provides a foundation for improving their representation in climate models. 

Rapid Room-Temperature Aerosol Dehydration (RTAD) is a novel, scalable drying technology for powderization and thermal stabilization of pharmaceutical drug products. Compared to conventional spray drying processes, typically using droplets of 10–200 lm in diameter generated by high-shear spraying, RTAD uses much smaller droplets with diameter 0.1 to 20 lm produced in modified liquid atomization processes. These fine droplets evaporate rapidly within 10–100 ms under room-temperature conditions, thereby reducing drying-induced stresses for thermally sensitive biologics. In this study, we used Green Fluorescent Protein (GFP) as a model biological molecule to optimize the design of the RTAD system and the process parameters. We experimentally investigated the effects of droplet size, multiphase flow patterns in the drying chamber, and application of polysorbate 20 as a model surfactant on GFP fluorescence after drying and powder reconstitution. The experiments demonstrated that the presence of surfactant in the formulation significantly influenced the GFP fluorescence intensity, especially for smaller droplets. The numerical studies using Computational Fluid Dynamics simulations revealed that the drying of droplets was dependent on the patterns of multiphase flow in the drying chamber, which can impact the intensity of GFP fluorescence in the produced dry powders. Non-axisymmetric flows and closed circulating streamlines near the drying gas inlet resulted in considerably longer particle residence times, which we infer means that GFP molecules were subjected to excess stress that negatively impacted the GFP fluorescence intensity. Through iterative optimization of the chamber design, process parameters and feedstock formulation, we achieved recovery of the GFP fluorescence intensity that exceeded 96% in the obtained dry powders. This work establishes GFP as a sensitive model biologic and its fluorescence intensity as a powerful tool to rapidly assess process efficiency and the ability to preserve bioactivity after dehydration. The study has broad implications for the design and scale-up of drying technologies, which can potentially transform the production of dry powder biopharmaceuticals. 

Surface tension gradients of air–liquid–air films play a key role in governing the dynamics of systems such as bubble caps, foams, bubble coalescence and soap films. Furthermore, for common fluids such as water, the flow due to surface tension gradients, i.e. Marangoni flow, is often inertial, due to the low viscosity and high velocities. In this paper, we consider the localised deposition of insoluble surfactants onto a thin air–liquid–air film, where the resulting flow is inertial. As observed by Chomaz (2001J. Fluid Mech.442, 387–409), the resulting governing equations with only inertia and Marangoni stress are similar to the compressible gas equations. Thus, shocks are expected to form. We derive similarity solutions associated with the development of such shocks, where the mathematical structure is closely related to the Burgers equation. It is shown that the nonlinearity of the surface tension isotherm has an effect on the strength of the shock. When regularisation mechanisms are included, the shock front can propagate and late-time similarity solutions are derived. The late-time similarity solution due to regularisation by capillary pressure alone was found by Eshimaet al.(2025Phys. Rev. Lett.134, 214002). Here, the regularisation mechanism is generalised to include viscous extensional stress.