The European Physical Journal. E, Soft Matter[JOURNAL]
Sun
200 papers
Dependence of ATP content in the formation of protrusions in DMPC GUVs under an AC electric field.
Ángeles-Robles G, Ruiz-Garcia J, Méndez JA … +1 more , Ortiz-Dosal LC
Eur Phys J E Soft Matter · 2026 Apr · PMID 41973276 · Publisher ↗
The cytoskeleton is an essential cell component. Many cellular processes that require changes in the cell structure depend on it. One of these processes is cell migration, which occurs through the formation of structures...
The cytoskeleton is an essential cell component. Many cellular processes that require changes in the cell structure depend on it. One of these processes is cell migration, which occurs through the formation of structures called protrusions that interact with other cytoskeletal components, enabling the cell to move slowly. These structures are formed by the polymerization of actin monomers, a process that requires the presence of ATP, as well as the exchange of divalent cations. In this work, we present a study on the formation of actin protrusions within DMPC giant unilamellar vesicles by varying the concentration of ATP, both in the absence and presence of MgCl. It was found that when the concentration of ATP in the overall protein buffer increases, these structures form and extend inside the vesicle without breaking it, even in the absence of MgCl. These protrusions are randomly oriented; however, when an alternating current electric field is applied, the protrusions align in the direction of the field in response to the polar nature of both lipids and actin filaments.
Mechanistic mapping of temperature-dependent ssDNA elasticity with oxDNA2 coarse-grained model.
Igwe IE, Abdulfatah S
Eur Phys J E Soft Matter · 2026 Apr · PMID 41966679 · Publisher ↗
The mechanical behavior of single-stranded DNA (ssDNA) controls its biological function and underpins the design of DNA-based nanodevices, yet the microscopic origin of temperature-dependent elasticity remains incomplete...
The mechanical behavior of single-stranded DNA (ssDNA) controls its biological function and underpins the design of DNA-based nanodevices, yet the microscopic origin of temperature-dependent elasticity remains incompletely quantified. Here, we use the salt-aware, sequence-dependent oxDNA2 coarse-grained model to map how intra-strand stacking and temperature jointly determine ssDNA mechanics for two prototypical homopolymers, poly(dA) and poly(dT), across 27-100 °C at 1.0 M monovalent salt. Large ensembles of independent simulations were used to extract equilibrium observables such as persistence length , radius of gyration , end-to-end distance , and equilibrium force-extension relations. We find that poly(dA) is substantially stiffer than poly(dT) at low temperature: = 44.8 ± 2.0 nm at 27 °C decreases to 10.0 ± 0.7 nm at 100 °C, while poly(dT) remains comparatively flexible, varying only from 1.40 ± 0.08 nm to 1.05 ± 0.04 nm. These macroscopic changes closely track the loss of intra-strand stacking. For poly(dA), the stacking fraction decreases from 0.70 ± 0.02 to 0.20 ± 0.01, whereas poly(dT) remains weakly stacked across the full range (< 0.10). Force-extension analysis shows that the wormlike chain (WLC) model captures low-force entropic elasticity but fails at intermediate extensions in strongly stacked poly(dA), where cooperative unstacking produces excess forces of ~ 8 to 10 pN near . The normalized root-mean-square residual at 27 °C is 0.22 for poly(dA), compared to 0.03 for poly(dT). When is normalized by its 27 °C value, both sequences collapse onto a single master curve as a function of stacking fraction (collapse slope ≈ 3.5 ± 0.3), indicating that fractional stacking loss serves as a unifying control parameter for thermal softening. These results quantitatively link microscopic stacking statistics to macroscopic elasticity, clarify the temperature-dependent limits of continuum polymer models, and provide a mechanistic framework for interpreting single-molecule stretching and ensemble measurements of ssDNA mechanics.
Kinetic theory of dilute weakly charged granular gases with hard-core and inverse power-law interactions under uniform shear flow.
Kobayashi Y, Kikuchi MR, Iizuka S … +1 more , Takada S
Eur Phys J E Soft Matter · 2026 Apr · PMID 41952017 · Publisher ↗
We develop a kinetic-theory framework to investigate the steady rheology of a dilute gas interacting via a repulsive potential under uniform shear flow. Starting from the Boltzmann equation with a restitution coefficient...
We develop a kinetic-theory framework to investigate the steady rheology of a dilute gas interacting via a repulsive potential under uniform shear flow. Starting from the Boltzmann equation with a restitution coefficient that depends on the impact velocity and potential strength, we derive evolution equations for the stress tensor based on Grad's moment expansion. The resulting expressions for the collisional rates and transport coefficients are fitted with simple analytical functions that capture their temperature dependence over a wide range of shear rates. Comparison with direct simulation Monte Carlo (DSMC) results shows excellent quantitative agreement for the shear stress, temperature anisotropy, and shear viscosity. We also analyze the velocity distribution functions, revealing that the system remains nearly Maxwellian even under strong shear.
Non-local rheology in granular media: a perspective on the 2015 EPJE Paper by Bouzid et al.
Pouliquen O
Eur Phys J E Soft Matter · 2026 Apr · PMID 41945266 · Publisher ↗
The study "Non-local rheology in dense granular flows: Revisiting the concept of fluidity," published in 2015 in The European Physical Journal E (vol. 38) by Mehdi Bouzid and collaborators, stands as an important contrib...
The study "Non-local rheology in dense granular flows: Revisiting the concept of fluidity," published in 2015 in The European Physical Journal E (vol. 38) by Mehdi Bouzid and collaborators, stands as an important contribution to the rheology of granular materials. In their work, the authors critically discuss the differences between proposed non-local models and provide clear pathways to discriminate between them. This perspective paper revisits the state of the art at the time of the Bouzid et al's publication, highlighting its role in inspiring subsequent research. We then explore recent advancements since 2015, which, while significant, have not yet fully resolve the questions originally raised by Bouzid et al.
Glassy dynamics and nanoconfinement: what we learned, what comes next.
Napolitano S
Eur Phys J E Soft Matter · 2026 Apr · PMID 41944979 · Publisher ↗
Over the past three decades, spatial confinement has reshaped our understanding of polymers as glass-forming materials. Rather than merely perturbing bulk behavior, geometric and interfacial constraints introduce new len...
Over the past three decades, spatial confinement has reshaped our understanding of polymers as glass-forming materials. Rather than merely perturbing bulk behavior, geometric and interfacial constraints introduce new length and time scales that actively transform materials response, underpinning a range of otherwise distinct phenomena, from microscopic dynamics and macroscopic relaxation to vitrification and mechanical properties. By reducing at least one system dimension to the nanoscale, combined experimental, theoretical, and simulation efforts have revealed how confinement selects which dynamic modes remain active, uncovering relaxation pathways that might be silent in the bulk. These convergent insights have matured into a robust conceptual framework, which continues to evolve as new questions emerge. This perspective focuses on three themes that I consider central to this evolution: the decoupling of thermal and dynamical signatures of the glass transition under confinement, the emergence of finite low-frequency rigidity in confined liquids and soft solids, and the stabilization of long-lived nonequilibrium states mediated by interfaces and reduced dimensionality. The discussion of these topics points toward a necessary evolution: further progress will require theories that move beyond equilibrium descriptions to explicitly incorporate nonequilibrium pathways and emergent microscopic routes to macroscopic relaxation, ultimately bridging the gap toward a more complete, predictive description of glassy polymer dynamics.
Inference of the 3D pressure field exerted by a single cell from a thin membrane transverse deformation.
Bédel Q, Dupré L, Destainville N
Eur Phys J E Soft Matter · 2026 Apr · PMID 41942677 · Full text
Numerous cell types relate to their immediate environment by exerting a three-dimensional pressure field on their environment, with components both longitudinal and transverse to the cell membrane. This pressure field ca...
Numerous cell types relate to their immediate environment by exerting a three-dimensional pressure field on their environment, with components both longitudinal and transverse to the cell membrane. This pressure field can in principle be measured by traction force microscopy experiments. Compared to other approaches, the technique of protrusion force microscopy gives access with high spatial resolution to the pressure field by measuring the deformation of a thin elastic membrane using atomic force microscopy (AFM). However, while the pressure field under interest is three-dimensional, the height profile measured by AFM is only one-dimensional. We propose a solution to this inverse problem and we explore its regime of applicability in the experimental context.
Formation of cylindrical shells via sphere packing from fluidized beds.
Oliveira VPS, Borges DS, Franklin EM … +1 more , Peixinho J
Eur Phys J E Soft Matter · 2026 Apr · PMID 41931265 · Full text
The results of a numerical investigation of fluidized beds of spherical particles in a narrow vertical cylindrical pipe, with particular attention to the spontaneous settling along the wall, are reported. Starting from a...
The results of a numerical investigation of fluidized beds of spherical particles in a narrow vertical cylindrical pipe, with particular attention to the spontaneous settling along the wall, are reported. Starting from a steady fluidized state, the particles fluctuate because of fluid-particle, particle-particle, and particle-wall interactions. The particles are heavier than the fluid, with diameters d yielding ratios of pipe to particle diameters and 4.7. For given ranges of flow velocities and bed sizes, particles settle on the wall, with a decrease in the bed height and particle fluctuations. Either a glass- or crystal-like shell forms along the pipe wall, in qualitative agreement with previous experiments. The polydispersity and the particle-particle friction are varied to test the stability of the particulate shell formation. The shell structure is analyzed by unwrapping it in a plane and locating all particles and their contact points, and we find that it exhibits a hexagonal lattice with a defects density that increases with polydispersity. The shell formation is hindered by polydispersity, and there exists a critical point for polydispersity above which a crystal-like shell is unstable. In a particular case of bidisperse beds, the crystal-like shell only appears when the particle-particle friction is high enough. Finally, we compute the contact forces within particle-particle chains and in particle-wall contacts, which sustain the cylindrical shell, highlighting the dominant role of particle-particle forces.
Perspective on "Active Brownian particles moving in a random Lorentz gas".
Reichhardt C, Reichhardt CJO
Eur Phys J E Soft Matter · 2026 Apr · PMID 41925789 · Full text
Self-propelled active matter can exhibit vastly different behavior than systems with purely Brownian motion. In Eur. Phys. J. E 40, 23 (2017), Zeitz, Wolf, and Stark compared an active matter particle with a Brownian par...
Self-propelled active matter can exhibit vastly different behavior than systems with purely Brownian motion. In Eur. Phys. J. E 40, 23 (2017), Zeitz, Wolf, and Stark compared an active matter particle with a Brownian particle moving in a random obstacle array. They showed that near the obstacle percolation density, both Brownian and active particles exhibit the same subdiffusive behavior, but the active particle reaches a steady state more rapidly. They also found that for high activity, the active particle has a lower effective diffusion than the Brownian particle due to the increased self-trapping effect generated by the activity. This result opens new directions for the study of active matter in disordered media, including bacteria in porous media, active colloids on quenched disorder, and active particles in crowded environments.
Dynamical networking of polymer networks with dedicated cross-linker particles.
du Toit N, Müller-Nedebock KK, Pellicane G
Eur Phys J E Soft Matter · 2026 Apr · PMID 41922872 · Full text
This paper extends a field-theoretical dynamical networking formalism for mesoscopic polymer dynamics to explicitly include dedicated cross-linker particles. Cross-linkers are represented within a Martin-Siggia-Rose gene...
This paper extends a field-theoretical dynamical networking formalism for mesoscopic polymer dynamics to explicitly include dedicated cross-linker particles. Cross-linkers are represented within a Martin-Siggia-Rose generating functional and reversibly coupled to polymers through Gaussian networking fields, enabling an approximation scheme that reduces their degrees of freedom while remaining compatible with polymer dynamics. The framework is applied to a two-species polymer system in which intra- and inter-species cross-linking are assigned different statistical advantages. Effective networking potentials are derived and used to calculate correlation functions and dynamic structure factors. To validate these results, molecular dynamics simulations of semi-flexible polymers with reversible intra- and inter-species cross-linking are performed. Simulations show that cross-linking decreases polymer persistence lengths and local alignment, and the resulting trajectories yield dynamic structure factors consistent with theoretical predictions. Qualitative comparison reveals that in both approaches, cross-linking broadens the diffusive peaks and enhances the high-frequency tails of the structure factors. Together, theory and simulation provide complementary insights into the dynamics of cross-linked polymers, establishing a tractable framework that captures essential features observed in experiments and offering a basis for exploring more complex synthetic and biological networks.
Influence of doublets on self-organization and viscoelasticity of model repulsive 2D binary colloids.
Hamid AH, Bécu L, Gonzalez-Rodriguez D … +1 more , Xu H
Eur Phys J E Soft Matter · 2026 Mar · PMID 41896498 · Publisher ↗
We study a two-dimensional binary mixture with different interaction strengths serving as a simplified model inspired by experimental colloidal systems. The investigations are carried out by molecular dynamics simulation...
We study a two-dimensional binary mixture with different interaction strengths serving as a simplified model inspired by experimental colloidal systems. The investigations are carried out by molecular dynamics simulations focusing on self-organization, dynamics, and viscoelasticity. The reference system is composed of spherical colloidal particles interacting with a short-ranged repulsive version of the Lennard-Jones pair potential, the Weeks-Chandler-Andersen (WCA) potential, with the interaction strength ; the second component, referred to as "doublets," interacts via the same potential, but with the interaction strength , while the cross-species interaction has the strength . We focus on the effect of doublets on system properties. To accurately compute the dynamic moduli, we fit the shear-stress autocorrelation function (SACF) to a double Kohlrausch-Williams-Watts (KWW) stretched (or compressed) exponential function, which provides a satisfactory approximation for both the fluid and solid phases. We perform simulations at fixed pressure, varying the fraction of doublets and the temperature. We observe that the doublets increase the melting temperature, diminish the diffusion of the reference species, and strongly affect the viscoelastic properties. Our results, arising from the competition between stronger pair interactions and the reduced density due to the presence of doublets, can be (partly) interpreted by effective hard disk diameters and associated effective packing fractions. These findings provide clear signatures that may be qualitatively compared to experiments with colloidal suspensions.
Structural and dynamic characterisation of charged microemulsions grafted with telechelic polymers at high dilution.
Elhajjam R, Khatouri M, Ahfir R … +5 more , Talha L, Basbassi Z, Arbia A, El Khaoui S, Filali M
Eur Phys J E Soft Matter · 2026 Mar · PMID 41851409 · Publisher ↗
Microemulsions are widely studied model colloidal systems due to their well-defined structure and tunable interactions. In this work, we investigate the structural and dynamic properties of a mixed system composed of mic...
Microemulsions are widely studied model colloidal systems due to their well-defined structure and tunable interactions. In this work, we investigate the structural and dynamic properties of a mixed system composed of microemulsion droplets grafted with a steric telechelic polymer, polyethylene oxide-C H (PEO-m), at a low volume fraction ( ). The microemulsions studied are direct (oil-in-water) microemulsions, stabilised by cetylpyridinium chloride (CpCl) as the surfactant and octanol as the co-surfactant. The interaction potential of this system is modelled using the Derjaguin-Landau-Verwey-Overbeek (DLVO) framework, which combines a hard sphere potential, a van der Waals potential, and a Coulomb potential. Three complementary approaches are employed: small-angle neutron scattering (SANS) experiments, Ornstein-Zernike integral equations with the hypernetted chain (HNC) closure, and molecular dynamics (MD) simulations. SANS results show that the microemulsion droplets exhibit a spherical shape with an average radius and a polydispersity and that this morphology remains unchanged as long as the number of grafted polymers does not exceed . However, for , both the average radius and the polydispersity decrease to and . These results also indicate that the addition of PEO-m strengthens the repulsive interactions between droplets, thereby confirming that this polymer effectively stabilises the microemulsions. The Ornstein-Zernike integral equation with the HNC closure is used to determine the parameters of the potential describing the interactions between droplets. These parameters are subsequently introduced into MD simulations to assess the dynamic properties of the system. The results show that the addition of PEO-m reduces droplet mobility, while the diffusion behaviour remains normal.
Spreading and absorption of silicone oil droplets on silicone elastomer films.
Dutcher L, Baylis B, Dutcher JR … +2 more , Raphaël É, Dalnoki-Veress K
Eur Phys J E Soft Matter · 2026 Mar · PMID 41851394 · Full text
When a liquid droplet completely wets a hard substrate, its spreading dynamics follow Tanner's law, with the droplet radius growing as the one-tenth power of time. Here, we investigate how these dynamics change when sili...
When a liquid droplet completely wets a hard substrate, its spreading dynamics follow Tanner's law, with the droplet radius growing as the one-tenth power of time. Here, we investigate how these dynamics change when silicone oil droplets spread on soft silicone elastomer and gel films supported by a rigid silicon substrate. While the droplets fully wet the elastomer surface, they also simultaneously swell the elastomer film. By varying the film thickness, we observe deviations from the classical power-law scaling, which we interpret in terms of changes to the effective stiffness and the absorption potential of the system. We describe the spreading behavior using a phenomenological model that accounts for both absorption and mechanical contributions..
Decoding soil properties from surface cracks using Minkowski functionals, junction crack angle distributions, and AI-based image analysis.
Daimari E, Ratna PS, Mouli PVSSRC … +1 more , Madhurima V
Eur Phys J E Soft Matter · 2026 Mar · PMID 41830988 · Publisher ↗
Desiccation cracks depend on the type of soil, with each type exhibiting a distinct pattern. In this study, we examined the evolution of the crack patterns in different soil types as well as with changes within the same...
Desiccation cracks depend on the type of soil, with each type exhibiting a distinct pattern. In this study, we examined the evolution of the crack patterns in different soil types as well as with changes within the same soil type. Physico-chemical studies of the sub-classes of soils, one taken from a flooding left bank and the other from a non-flooding right bank, were nearly identical. However, desiccation crack experiments, analysed using morphological descriptors including Minkowski functionals and junction crack angle distribution, exhibited distinct patterns and descriptors, indicating these to be good fingerprints of soil types and sub-types. To refine this analysis, the image dataset from the experiments was used to train convolutional neural network algorithms. 60% data were used for training, and 100% prediction accuracy was achieved in both major and sub-major classification. The results of this study shows the versatility of the study of desiccation crack pattern studies and how coupling it with deep learning leads to accurate identification of the soil types, with applications in agricultural soil assessment, planetary terrain studies, geotechnical engineering, floodplain and river-basin monitoring, and image-based soil classification.
Endophytic fungi of Aegle marmelos as a source of novel antibacterials and anti-SARS-CoV agents.
Goyal S, Bansal P, Kumar P … +9 more , Kumar D, Sharma G, Sharma A, Gupta B, Gupta M, Kumar R, Umar A, Almas T, Baskoutas S
Eur Phys J E Soft Matter · 2026 Mar · PMID 41811556 · Full text
Drug resistance in microorganisms is a growing global threat, highlighting the urgent need for novel therapeutic agents. This study evaluates the antibacterial and anti-SARS-CoV potential of fungal endophytes isolated fr...
Drug resistance in microorganisms is a growing global threat, highlighting the urgent need for novel therapeutic agents. This study evaluates the antibacterial and anti-SARS-CoV potential of fungal endophytes isolated from A. marmelos. Among 16 endophytes screened, the ethyl acetate extract of the #3 AMLBF strain (Fusarium vanettenii) exhibited the strongest antibacterial activity against several pathogens. This extract showed minimum inhibitory concentrations (MICs) ranging from 0.49 to 0.8 µg/ml. GC/MS analysis of the active extract identified 45 compounds. Furthermore, molecular docking against the SARS-CoV-2 spike glycoprotein revealed nine potential ligands, with Anthraergosta-5,7,9,22-tetren-3-ol p-chlorobenzoate showing the most potent binding affinity (- 10.2 kcal/mol), a value exceeding that of the standard chloroquine (- 6.5 kcal/mol). These results indicate that the organic extract from this fungal strain is a promising candidate for the discovery of new antimicrobial agents.
Radiation-entropy generation by leaf and negentropy build-up of plant as dissipative structure.
Mahulikar SP, Rastogi P, Erkoreka A
Eur Phys J E Soft Matter · 2026 Mar · PMID 41811416 · Full text
Photosynthesis is a simple reaction for any plant, but it has not been achieved artificially due to the difficulty in radiation entropy production by processing PAR (photosynthetically active radiation). In this study, a...
Photosynthesis is a simple reaction for any plant, but it has not been achieved artificially due to the difficulty in radiation entropy production by processing PAR (photosynthetically active radiation). In this study, a plant is shown to be a self-organising dissipative structure; since, it's leaf generates radiation entropy for the existence of plant with possible growth. Entropy-energy ratio (s) of PAR released after processing (s) much exceeds s of light absorbed, s (< < s). Plant builds its negentropy by the difference, , but only a part of this difference can be the source of free energy as plant-growth. The remaining part of is dissipated as the excess payment of negentropy debt, towards mandatory 2nd Law compliance. Change from low s to high s by the plant-leaf is amplified by a huge factor, c, while determining ; where, c is the speed of light. Therefore, even a small increase in s and small reduction in s can significantly increase . Thermodynamic performance of photosynthesis depends on the processing level of PAR, , , and is limited by the maximum photosynthetic efficiency in PAR, (it increases with ).
Analysis of MHD rayleigh-taylor instability in a walter's B fluid with thermal and mass diffusion effects.
Bharti KP, Awasthi MK, Shukla AK … +1 more , Datt G
Eur Phys J E Soft Matter · 2026 Mar · PMID 41770464 · Publisher ↗
An analytical and numerical investigation of Rayleigh-Taylor instability has been carried out within a planner configuration under the influence of a vertically imposed magnetic field, through viscous potential flow theo...
An analytical and numerical investigation of Rayleigh-Taylor instability has been carried out within a planner configuration under the influence of a vertically imposed magnetic field, through viscous potential flow theory. The instability is examined for the configuration in which a Walter's B viscoelastic fluid overlies a Newtonian viscous fluid embedded in a porous medium, with simultaneous heat and mass transfer permitted across the interface. The dispersion relation between perturbation growth rate and wave number is established via normal mode analysis. This relation is investigated using the Newton-Raphson method, which facilitates the identification of the influence of various non-dimensional physical parameters, determining whether they suppress or amplify the perturbation growth. The study reveals that a vertically oriented magnetic field and an increased porosity of the medium enhance the amplification of perturbations, while an increased thermal flux across the interface counteracts this tendency, thereby diminishing the growth of instability.
Free-interface convective mixing in porous media: 2D and 3D numerical simulations.
Imuetinyan H, Musacchio S, Croccolo F … +1 more , Boffetta G
Eur Phys J E Soft Matter · 2026 Mar · PMID 41770248 · Publisher ↗
We investigate convective mixing in porous media in the presence of a free interface separating two miscible fluids initially arranged in a stable configuration. This problem is motivated by the dynamics of supercritical...
We investigate convective mixing in porous media in the presence of a free interface separating two miscible fluids initially arranged in a stable configuration. This problem is motivated by the dynamics of supercritical overlying a brine-saturated porous medium, as well as analogous laboratory experiments. Diffusion of the lighter upper layer into the denser lower layer results in a layer with a density greater than that of the denser lower layer, which then induces an unstable stratification that triggers convection. Using high-resolution direct numerical simulations, we analyse the system dynamics in both two- and three-dimensional geometries and for different diffusivities. Our results show that in 2D the process is faster, with dissolution fluxes about higher than in 3D. Convective plumes deform the initially flat interface, creating an iso-concentration surface whose vertical extent increases over time. These findings highlight the need for caution when extrapolating two-dimensional results to three-dimensional applications.
Geometric confinement reveals scale-free velocity correlations in epithelial cell monolayer.
Duprez G, Durande M, Graner F … +1 more , Delanoë-Ayari H
Eur Phys J E Soft Matter · 2026 Feb · PMID 41748795 · Publisher ↗
Collective cell flows are a hallmark of tissue dynamics in development, wound healing, and various diseases. Here, we investigate how the size, shape, topology and rigidity of patterned substrate influence the organizati...
Collective cell flows are a hallmark of tissue dynamics in development, wound healing, and various diseases. Here, we investigate how the size, shape, topology and rigidity of patterned substrate influence the organization of flows and mechanical fields in an epithelial MDCK cell monolayer at several time and space scales. Using micropatterned substrates with and without free front (a strip and a closed racetrack), we show that confinement and obstacles induce spatial heterogeneities in velocity and force fields, leading to the emergence of domains, waves, and long-range correlations. We show that spatial velocity correlations are scale-free, following a power law whose exponent evolves as the monolayer matures. This challenges the notion of a single intrinsic correlation length. We also show that in absence of free front, spontaneous collective motions are stronger on soft than on hard substrate. Our findings provide new insights into the rheology of epithelial tissues and the interplay between mechanics and collective migration.
Hydrophilicity controls thermodiffusion in alkylammonium chlorides.
Rudani BA, Kriegs H, Wiegand S
Eur Phys J E Soft Matter · 2026 Feb · PMID 41733823 · Full text
In this study, we examine the Soret effect of ammonium chloride ( Cl) and its alkyl-substituted derivatives: dimethylammonium chloride (DMACl), ethylammonium chloride (EACl), and trimethylammonium chloride (TMACl) in aq...
In this study, we examine the Soret effect of ammonium chloride ( Cl) and its alkyl-substituted derivatives: dimethylammonium chloride (DMACl), ethylammonium chloride (EACl), and trimethylammonium chloride (TMACl) in aqueous solution using infrared thermal diffusion forced Rayleigh scattering. The Soret coefficient, , increases systematically with alkyl substitution, following the trend Cl DMACl < EACl TMACl, while hydrophilicity decreases correspondingly. Across the investigated temperature range ( C) and concentrations (1-4 mol/kg), increases with both temperature and the degree of alkyl substitution. However, the concentration dependence varies among the salts. DMACl, EACl, and TMACl exhibit decreasing with increasing concentration and are predominantly thermophobic; TMACl remains thermophobic under all conditions. In contrast, Cl shows a non-monotonic concentration dependence above C and is largely thermophilic. We discuss the origin of this minimum at elevated temperatures in relation to other aqueous salt systems that exhibit non-monotonic behavior of with respect to concentration. Overall, each additional alkyl substitution decreases the temperature sensitivity of the Soret coefficient, , consistent with reduced solute hydrophilicity. Furthermore, we observe a clear correlation between the thermal diffusion coefficient and the thermal expansion coefficient in these aqueous electrolyte solutions. This is consistent with the trends reported for nonpolar organic mixtures and aqueous solutions of non-ionic solutes. These findings highlight thermodiffusion as a sensitive probe for understanding how hydrophilicity and ion-specific interactions govern molecular transport in aqueous environments.
Coupled interplays between proliferation and hydrodynamic interactions modulate the transport of chemotactic entities.
William K, Didier BB
Eur Phys J E Soft Matter · 2026 Feb · PMID 41733839 · Publisher ↗
This study investigates the stability properties of two interacting chemotactic populations by introducing an extended mathematical model that simultaneously incorporates competitive hydrodynamic interactions and kinetic...
This study investigates the stability properties of two interacting chemotactic populations by introducing an extended mathematical model that simultaneously incorporates competitive hydrodynamic interactions and kinetic growth dynamics. Using a standard plane wave analysis, we demonstrate that the interplay between hydrodynamic and kinetic interactions governs the system's stability. Specifically, the system remains stable for long wave vectors when strong-strong kinetic interactions are coupled with either weak-weak or strong-weak hydrodynamic interactions. Conversely, stability for short wave vectors is achieved when weak-weak kinetic interactions are paired with similar hydrodynamic configurations. To explore localized dynamics, we perform a generalized linear stability analysis using spatially localized functions. This reveals the emergence of rapid oscillations that modulate both stationary and non-stationary wave patterns. Modulated structures are sensitive to the choice of the envelope function: waves initiated with Gaussian-type profiles are more prone to instability than those generated with secant-type functions. Numerical simulations further illustrate the formation of stable non-uniformly distributed structures. The generalized perturbation framework presented here highlights the delicate balance between hydrodynamics and competitive interactions occurring within biological tissues during invasion, showcasing new insights into collective transport, pattern formation, and strategies for organ repair.
About
- Frequency
- Sun
- Papers found
- 200
- RSS feed
- Subscribe