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.
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http://dx.doi.org/10.1103/PhysRevE.106.064608 | DOI Listing |
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 PDFInt Immunopharmacol
January 2025
Department of Orthopedics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325005, Zhejiang, China; Geriatrics Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China. Electronic address:
J Phys Chem A
January 2025
Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States.
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 PDFMed Phys
November 2024
Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
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).
J Phys Chem A
December 2024
ISM, UMR 5255, CNRS, Bordeaux INP, Université de Bordeaux, F-33400 Talence, France.
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