Diffusion of a tracer in a dense mixture of soft particles connected to different thermostats.

Phys Rev E

Sorbonne Université, CNRS, Laboratoire PHENIX (Physico-Chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX), 4 Place Jussieu, 75005 Paris, France.

Published: December 2022

We study the dynamics of a tracer in a dense mixture of particles connected to different thermostats. Starting from the overdamped Langevin equations that describe the evolution of the system, we derive the expression of the self-diffusion coefficient of a tagged particle in the suspension, in the limit of soft interactions between the particles. Our derivation, which relies on the linearization of the Dean-Kawasaki equations obeyed by the density fields and on a path-integral representation of the dynamics of the tracer, extends previous derivations that held for tracers in contact with a single bath. Our analytical result is confronted to results from Brownian dynamics simulations. The agreement with numerical simulations is very good even for high densities. We show how the diffusivity of tracers can be affected by the activity of a dense environment of soft particles that may represent polymer coils-a result that could be of relevance in the interpretation of measurements of diffusivity in biological media. Finally, our analytical result is general and can be applied to the diffusion of tracers coupled to different types of fluctuating environments, provided that their evolution equations are linear and that the coupling between the tracer and the bath is weak.

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.106.064608DOI Listing

Publication Analysis

Top Keywords

tracer dense
8
dense mixture
8
soft particles
8
particles connected
8
connected thermostats
8
dynamics tracer
8
analytical result
8
diffusion tracer
4
mixture soft
4
particles
4

Similar Publications

Adult Embryonal Rhabdomyosarcoma of the Prostate Presented on 18F-FDG and Al18F-FAPI-74 PET/CT.

Clin Nucl Med

December 2024

From the Department of Nuclear Medicine (PET-CT Center), National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

A 21-year-old man with a 2-week history of abdominal pain and urinary hesitancy was admitted to our hospital. Sarcoma was suspected based on his PSA level, age, and MRI findings. He underwent 18F-FDG and Al18F-FAPI-74 PET/CT scans.

View Article and Find Full Text PDF
Article Synopsis
  • Mitochondrial dysfunction leads to chondrocyte aging, contributing to osteoarthritis (OA) and it remains uncertain if mesenchymal stem cells (MSCs) can help restore mitochondrial function in chondrocytes or reverse OA progression.
  • The study utilized mitochondria-rich extracellular vesicles (MEV) from stem cells to determine their impact on both healthy and stressed human articular chondrocytes in vitro, and further tested their effects in OA rats.
  • Findings revealed that MEV could enter chondrocytes, reduce oxidative stress markers, enhance mitochondrial function, and effectively reduce cartilage degeneration in OA rats, suggesting a potential therapeutic approach for OA management.
View Article and Find Full Text PDF

Highly energetic boron (B) particles embedded in hydroxyl-terminated polybutadiene (HTPB) thermosetting polymers represent stable solid-state fuel. Laser-heating of levitated B/HTPB and pure HTPB particles in a controlled atmosphere revealed spontaneous ignition of B/HTPB in air, allowing for examination of the exclusive roles of boron. These ignition events are probed via simultaneous spectroscopic diagnostics: Raman and infrared spectroscopy, temporally resolved high-speed optical and infrared cameras, and ultraviolet-visible (UV-vis) spectroscopy.

View Article and Find Full Text PDF

Background: Voxel-based analysis (VBA) for population level radiotherapy (RT) outcomes modeling requires topology preserving inter-patient deformable image registration (DIR) that preserves tumors on moving images while avoiding unrealistic deformations due to tumors occurring on fixed images.

Purpose: We developed a tumor-aware recurrent registration (TRACER) deep learning (DL) method and evaluated its suitability for VBA.

Methods: TRACER consists of encoder layers implemented with stacked 3D convolutional long short term memory network (3D-CLSTM) followed by decoder and spatial transform layers to compute dense deformation vector field (DVF).

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the reactions between nitrogen dioxide (NO) with atomic oxygen (O) and atomic carbon (C) at low temperatures using a supersonic flow reactor.
  • The reactions were monitored using different detection methods, revealing that the rate of O + NO reactions increases significantly as temperature decreases, while C + NO reactions are studied for the first time.
  • Simulations suggest that while gas-phase NO abundances are low in dense interstellar clouds, higher levels of NO may be found on interstellar dust grains, indicating potential for detection in warmer areas.
View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!